PSI Conversion

[Swain]

I have a PSI conversion wire harness in my 68 Camaro with a T56 trans.
Engine LS3
Do u need to have the brake switch hooked up? I cannot get the car to fire, and the guy who wired the car didn't hook up the brake switch. Any ideas?

[XLexusTech]

I have a PSI conversion wire harness in my 68 Camaro with a T56 trans.
Engine LS3
Do u need to have the brake switch hooked up? I cannot get the car to fire, and the guy who wired the car didn't hook up the brake switch. Any ideas?

Not only do you need it hooked up but you need a modern switch... Car won't crank without brake petal depressed

http://www.psiconversion.com/tech_articles/KIT-1002%20TCC%20SWITCH%20INSTRUCTIONS.pdf

[Swain]

Thank you I figured it needed to be wired.

Keep you posted

[dhutton]

I thought the TCC (Torque Converter Clutch) signal was only needed with the auto trans. At least that was the case with the LS1 builds I did.

Is the car cranking? Is there provision for a clutch safety switch in the harness?

A lot of guys make the mistake of connecting the ECM power to the power that is not hot when cranking. It needs to be connected to power that is hot both when cranking and running.

Don

[Swain]

Put a new cam sensor in still not fire.

[andrewb70]

....
A lot of guys make the mistake of connecting the ECM power to the power that is not hot when cranking. It needs to be connected to power that is hot both when cranking and running.

Don

^^^This...

Andrew

[gerno]

I used PSI and had a firing issue too due to the tune and VATS. I had to add a wire to the harness and put it to constant ground. I forget exactly which one it was but will see if I can find it tonight.

You can and google it to come up with the wire, that's how I figured it out.

[cpd004]

Do you have fuel at the rail?

[Swain]

Yes fuel at rails. I did notice the power dropped from 12v to 9.8V when cranking so I'm charging the battery. Maybe the ignition switch could be bad also. Trying to figure this out.

[cpd004]

When cranking, do you have spark?

[Swain]

No spark

[cpd004]

No spark

Then you must have a fuse blown in the PSi fuse block or you might not have correctly wired 12v to one of the wires necessary. If I remember correctly, there is a red wire that requires positive all the time and another wire that is specific to the fuel pump. Since it doesn't fire and die quickly, the fuel pump relay is probably wired correctly. The thick red supply wire may not be. Double check this wire. I think it goes directly to one of the relays. I'm relying on memory so hopefully I'm remembering all this correctly.

[cpd004]

It should be terminal 85 on the relay opposite of the fuel pump.

[Swain]

Then you must have a fuse blown in the PSi fuse block or you might not have correctly wired 12v to one of the wires necessary. If I remember correctly, there is a red wire that requires positive all the time and another wire that is specific to the fuel pump. Since it doesn't fire and die quickly, the fuel pump relay is probably wired correctly. The thick red supply wire may not be. Double check this wire. I think it goes directly to one of the relays. I'm relying on memory so hopefully I'm remembering all this correctly.

I checked that and it's working on key on and cranking. Think maybe the volts being low might of been it. I'll test it in a hour again

[Swain]

Volts drop down to under 10 while cracking. Not sure what the problem is ahhh

[cpd004]

Volts drop down to under 10 while cracking. Not sure what the problem is ahhh

I think that'd be fine to start it. Was VATS disabled?

Where are you measuring that voltage drop at?

[Swain]

I think that'd be fine to start it. Was VATS disabled?

Where are you measuring that voltage drop at?

At the red wire that comes off the fuse box also another hot wire. I bought the harness from a forum member maybe they weren't deleted. I'll call PSI Monday

[dhutton]

At the red wire that comes off the fuse box also another hot wire. I bought the harness from a forum member maybe they weren't deleted. I'll call PSI Monday

VATS delete is in the tune, not the harness. If it is not deleted, it will start and run briefly.

Don

[Swain]

VATS delete is in the tune, not the harness. If it is not deleted, it will start and run briefly.

Don

Sorry I meant ECU and Harness

[79 Camaro]

If you hooked up the 12 volt switched to the original wire that runs to the coil and it was older style points ignition the coil wire will have a resistor built limiting voltage during run.

I've never heard of a brake light switch wired to the ECM when using a manual trans that would prevent it from starting. Only time I've seen it was to make the reverse lock out work like stock.

Try wiring the switched 12 volt to 12 volt constant just temporarily to see if it will fire. If it does disconnecting the wire will shut the computer down and shut off the engine.

From what I've read a bad cam sensor will not shut the engine down but a bad crank sensor will.

[Vega$69]

With a PSI harness you do not need a brake switch with a manual.

If you wired in a neutral safety or clutch switch it would not crank so thats not the problem.

When you first turn the key on you should hear the fuel pump run for a few seconds. That would indicate the fuel pump relay is working.

Then you need to determine if the ignition relay is working. The easiest way is to touch the relay and have someone turn key on to see if it clicks on.

The other common issue with not starting is the ground wires that attach to the head are either not connected or loose.

[Swain]

If you hooked up the 12 volt switched to the original wire that runs to the coil and it was older style points ignition the coil wire will have a resistor built limiting voltage during run.

I've never heard of a brake light switch wired to the ECM when using a manual trans that would prevent it from starting. Only time I've seen it was to make the reverse lock out work like stock.

Try wiring the switched 12 volt to 12 volt constant just temporarily to see if it will fire. If it does disconnecting the wire will shut the computer down and shut off the engine.

From what I've read a bad cam sensor will not shut the engine down but a bad crank sensor will.

I ran a constant hot wire still nothing. Fans come on right away I heard that means theres a code. Shipping the ECU out to PSI today. This will be the best thing to do as they can program it to my specs.

[Vega$69]

I ran a constant hot wire still nothing. Fans come on right away I heard that means theres a code. Shipping the ECU out to PSI today. This will be the best thing to do as they can program it to my specs.

Did you pull codes?

I had the same issue with the fans and the harness/ECU I used on my LS7 Build from PSI. As I recall the fan set up was set wrong in the ECM. I have HP Tuner and was able to correct it.

[cpd004]

One thing that can make the fans come on (provided the ECM is configured properly for all else) is not hooking up some sort of check engine light.

[dhutton]

I recommend a low cost code scanner if you don't have one. Get one that lets you reset codes too. Very handy for these swaps.

Don

[Swain]

I recommend a low cost code scanner if you don't have one. Get one that lets you reset codes too. Very handy for these swaps.

Don

I have a scanner it will no link to ECU.

Tried everything lol.

[cpd004]

My scanner wouldn't link when a fuse blew on the PSi harness. Changed the fuse and everything worked.

[dhutton]

I have a scanner it will no link to ECU.

Tried everything lol.

Damn, you at least get A for effort.. :)

Don

[Swain]

My scanner wouldn't link when a fuse blew on the PSi harness. Changed the fuse and everything worked.

Checked all the fuses 5 times or more ha. I wish it was simple something so simple. Prolly is

[dhutton]

Checked all the fuses 5 times or more ha. I wish it was simple something so simple. Prolly is

What about all your grounds? How is everything grounded?

Don

[cpd004]

Do you 'feel' the other relay click when you turn the key?

[Swain]

What about all your grounds? How is everything grounded?

Don

I have grounds all over the place. I will see what PSI can come up with later this week. Hopefully it is my wiring or something easy. They will make sure the ECU is programmed to my specs.

[dhutton]

I have grounds all over the place. I will see what PSI can come up with later this week. Hopefully it is my wiring or something easy. They will make sure the ECU is programmed to my specs.

Heavy grounds from the battery to the block and body? Ground strap from the block to the body? ECM needs a nice clean ground.

Don

[Swain]

Heavy grounds from the battery to the block and body? Ground strap from the block to the body? ECM needs a nice clean ground.

Don

I have a heavy wire straight to the block. then Ground to the Subframe. I have sold mounts on the subframe.

Only thing it could be maybe I need a better clean ground to the body.

The ECU is grounded to the body.

[TomM]

I have a scanner it will no link to ECU.

Tried everything lol.

This might be a clue......

You need to constant hot to the PCM, fused from the battery. The you need your keyed hot(which you have already verified). Once you plug in your scanner and turn the key, you should be able to connect to your PCM. If not, either the OBD connector is not wired correctly, or you don't have computer power, i.e., computer not booting up.

Your OBD connector should have a hot wire from the keyed hot and then a ground. The other wire goes to the PCM. You can check the pin with a volt meter once you turn the key on and see if there is power at the OBD connector.

That is what I would check first.

T,

[cpd004]

This might be a clue......

You need to constant hot to the PCM, fused from the battery. The you need your keyed hot(which you have already verified). Once you plug in your scanner and turn the key, you should be able to connect to your PCM. If not, either the OBD connector is not wired correctly, or you don't have computer power, i.e., computer not booting up.

Your OBD connector should have a hot wire from the keyed hot and then a ground. The other wire goes to the PCM. You can check the pin with a volt meter once you turn the key on and see if there is power at the OBD connector.

That is what I would check first.

T,


That is why I asked if the other relay 'clicks'. It is possible the feed to one of the terminals from the back has come loose (possibly at 85). Also possible but rare is a bad relay. This connection is made by the end user with a provided female terminal.

See pages 13 & 14 here for some specific info:

http://www.psiconversion.com/tech_articles/HAR-1017%20LS1%20DBW%20Harness%20Instructions.pdf

[dhutton]

I have a heavy wire straight to the block. then Ground to the Subframe. I have sold mounts on the subframe.

Only thing it could be maybe I need a better clean ground to the body.

The ECU is grounded to the body.

There is normally a good thick braided ground from the block to the body. The ECM is normally grounded to the block in the factory harness if I remember right.

Don

[Swain]

Thanks for all the feedback everyone. I will let everyone know what they say when they get to it. I will go over all my grounds tonight. Maybe add a few more.

I will keep everyone posted.

[dhutton]

Thanks for all the feedback everyone. I will let everyone know what they say when they get to it. I will go over all my grounds tonight. Maybe add a few more.

I will keep everyone posted.

See steps 5.7 through 5.9 on page 7 for detailed grounding instructions for your harness:

http://www.psiconversion.com/tech_articles/MAN-1021_LS2-LS3_Harness_Instructions.pdf


Don

[youthpastor]

I had 2 PSI computers that had the VAT's removed but...there was a security feature that was not turned off. Would crank but no fire

Does it fire with a little air intake cleaner sprayed in the throttle body?

Injector pulse?

That is my guess.

[Swain]

I had 2 PSI computers that had the VAT's removed but...there was a security feature that was not turned off. Would crank but no fire

Does it fire with a little air intake cleaner sprayed in the throttle body?

Injector pulse?

That is my guess.

Didn't try to spray anything in the TB. Their was no spark so didn't want to waste my time. They should have the ECU tomorrow so we should know something soon.

[Vega$69]

Didn't try to spray anything in the TB. Their was no spark so didn't want to waste my time. They should have the ECU tomorrow so we should know something soon.

Good. That's not a good idea IMO

[Swain]

Well not sure what was wrong with my ECU. Called PSI this AM they said they were going to send me out a new one Programmed to my specs at a discounted rate. Can't complain since I didnt buy the kit directly from them new. Hopefully when I get back into town next week I can get it installed and try to fire it up again.

[Swain]

So I got the ECU back today. Fans stopped coming on right away so that's the only good news. Engine still will not fire. I added two more grounds.
Guess ill have to have someone come over and check the car out.

will the knock sensors not let it fire if they are bad?

What else could it be am I missing something.

[Swain]

So I got the ECU back today. Fans stopped coming on right away so that's the only good news. Engine still will not fire. I added two more grounds.
Guess ill have to have someone come over and check the car out.

will the knock sensors not let it fire if they are bad?

What else could it be am I missing something.

[Vega$69]

So I got the ECU back today. Fans stopped coming on right away so that's the only good news. Engine still will not fire. I added two more grounds.
Guess ill have to have someone come over and check the car out.

will the knock sensors not let it fire if they are bad?

What else could it be am I missing something.

OK

#1 is the fuel pump coming on when key is on position? With key on push schrader valve of fuel rail to verify you have fuel pressure to the fuel rail. Or if you hear pump running with key on turn key off and check. There will still be pressure in the fuel rail.

How is your fuel system plumbed?

#2 Does the Ignition Relay Click when you turn the key on. If you have to pull the pump relay and have some turn key on and listen for relay click.

There are 2 grounds on the PSI harness that mount to the rear of the heads.

I assume crank and cam sensor are connected?

knock sensor will not keep it from starting

[Swain]

Finally changed the coil wires around and it fired for a sec. The injectors are clogged. You can smell stale gas when we pulled them out. The fuel must of been stuck in the rails for a year or so. Can they be cleaned easily ?

[Vince@Meanstreets]

Finally changed the coil wires around and it fired for a sec. The injectors are clogged. You can smell stale gas when we pulled them out. The fuel must of been stuck in the rails for a year or so. Can they be cleaned easily ?

depends on what it is Jason....that long if open might be corrosion due to moisture. I'd start by pulling the rail and popping out the injectors and inspect the inlet side. your getting closer.

[IndyNova]

Take a syringe (meat injector works good) and some rubber hose. Slide the hose over the inlet side of injector, fill syringe up with carb/brake cleaner, rig up wires to a battery. I used alligator clips and connected one end to the neg post, and one end you will use to intermittently touch to the positive side to operate the injector. As you cylce the power for the injector, push the cleaner through the injector. There are various videos on youtube showing this procedure. I did this on mine to clean them. Hope this helps. I'm having a similar issue with mine, although mine wants to run for a coupe seconds and then pop and backfire and die out

[Musclerodz]

Finally changed the coil wires around and it fired for a sec. The injectors are clogged. You can smell stale gas when we pulled them out. The fuel must of been stuck in the rails for a year or so. Can they be cleaned easily ?Did you swap the coil harness from side to side?

[Swain]

Did you swap the coil harness from side to side?

Yes.

New injectors should be here tomorrow

[Vega$69]

Yes.

New injectors should be here tomorrow

Installing new injectors is definitely the smart way to go. :gitrdun:

[Swain]

How do you know what end of the coil harness goes. I think this could be my problem. Firring order must be off

[Vega$69]

How do you know what end of the coil harness goes. I think this could be my problem. Firring order must be off

I thought the injectors were clogged?

The PSI harness (as well as others) pretty much lay in the way they go. Would have to work at it to cross them up.

[Swain]

They were clogged. My car tried to start then will backfire. It's gotta be something with the ignition.

The coil harness is a GM Harness not a PSI piece

[Musclerodz]

They were clogged. My car tried to start then will backfire. It's gotta be something with the ignition.

The coil harness is a GM Harness not a PSI piece

the coil harness can easily be flipped, just need to check color coding to make sure its flipped the right way. Are you able to put a scanner on it and see if there is any codes?

[Swain]

the coil harness can easily be flipped, just need to check color coding to make sure its flipped the right way. Are you able to put a scanner on it and see if there is any codes?

I have the colors matching at the Harness connection.

My question is how does it know which coil is which?

The car will spin over and sometimes try to START AND BACK FIRE

My scanner will not read it for some reason. GOing to ground the valve covers to the block tonight see if that helps.

[Swain]

Just ordered a crank position sensor we will see if that helps any

[Vince@Meanstreets]

There is a coil circuit wire coming from the PCM in that bundle, wrong wire on the wrong coil and you will get a miss-fire. Let me see if I can find my notes for the Coil pack harness.

[Swain]

There is a coil circuit wire coming from the PCM in that bundle, wrong wire on the wrong coil and you will get a miss-fire. Let me see if I can find my notes for the Coil pack harness.

Ok thank you

[Musclerodz]

make sure you have GM crank and cam sensors. We have had issues with the cheap ones. Do you have the correct MAF? have you tried unhooking it and trying to start it in speed density mode?

[Vince@Meanstreets]

Ok thank you

My notes are jumbled and its hard to read so I found a picture.

Pink ignition power
XX PCM driver cylinder specific.
Tan
Black ground


XX=
Purple front or 1st cylinder
LT Blue 2nd cylinder
Green 3rd cylinder
Red 4th cylinder

I verified it with the other side. Its the same.

[Swain]

Awesome thank you.



My notes are jumbled and its hard to read so I found a picture.

Pink ignition power
XX PCM driver cylinder specific.
Tan
Black ground


XX=
Purple front or 1st cylinder
LT Blue 2nd cylinder
Green 3rd cylinder
Red 4th cylinder

I verified it with the other side. Its the same.

[Swain]

So it seems like it's a fuel issue. If I spray starter fluid it will fire. Thinking the corvette style fuel regulator might be the problem. Can I just run the pump right too the rails?

[Vince@Meanstreets]

So it seems like it's a fuel issue. If I spray starter fluid it will fire. Thinking the corvette style fuel regulator might be the problem. Can I just run the pump right too the rails?

Oh, did you fall for the feed line and return line trick? Outer port is the pressure feed and the center port is the return. Check that first.

Depends on what your full pressure is on that pump. 60 psi yes. 100 psi no.

[Swain]

Oh, did you fall for the feed line and return line trick? Outer port is the pressure feed and the center port is the return. Check that first.

Depends on what your full pressure is on that pump. 60 psi yes. 100 psi no.

I had it right sounded like it starved for fuel then switched it no pressure. Gotta switch it back. I mean the injectors are good. I need to test the pressure

[71RS/SS396]

It's not the crank sensor, it will not even try to fire if the crank sensor signal is missing. If your tach is showing any rpm when your turning it over the crank sensor is fine. It will do exactly what your describing if the cam sensor or circuit is bad though and it will likely even start if you keep cranking it with a bad cam sensor. I would verify the fuel pressure before I went any further.

[TomM]

So it seems like it's a fuel issue. If I spray starter fluid it will fire. Thinking the corvette style fuel regulator might be the problem. Can I just run the pump right too the rails?

No, it needs to be regulated, will cause too much pressure and an o-ring could fail....

T,

[Vega$69]

Is this a GM Performance harness or take out that has been reworked?

I would recheck the pressure reg installation. Outer port feed from fuel pump center opposite to fuel rail. Also make sure you have the lines hooked up correctly to the fuel pump.

What tank and pump set up ar you using.

[Swain]

Is this a GM Performance harness or take out that has been reworked?

I would recheck the pressure reg installation. Outer port feed from fuel pump center opposite to fuel rail. Also make sure you have the lines hooked up correctly to the fuel pump.

What tank and pump set up ar you using.

The Harness was made by PSI

[Vega$69]

The Harness was made by PSI

Ok. So it's a psi harness and you're plugging into the GM Coil harness

You can T into the fuel line at the fuel rail And temp in a fuel pressure gauge.

[Swain]

Ok. So it's a psi harness and you're plugging into the GM Coil harness

You can T into the fuel line at the fuel rail And temp in a fuel pressure gauge.

Tonight im going to run a gauge to see what the PSI is? If its too low hopefully thats the Problem. Maybe the Corvette Regulator is no good? ahhhhhhhhhhhhhhh

One day she will fire.

:weld:

[Vega$69]

Tonight im going to run a gauge to see what the PSI is? If its too low hopefully thats the Problem. Maybe the Corvette Regulator is no good? ahhhhhhhhhhhhhhh

One day she will fire.

:weld:

What fuel tank and pump do you have?

[Swain]

What fuel tank and pump do you have?

DSE LT1 tank with a Outlet and return feed

[Vega$69]

Do you have 24 or 58 tooth reductor?


And is the ECU correct for the reductor you have?

[Swain]

Do you have 24 or 58 tooth reductor?


And is the ECU correct for the reductor you have?

58 and yes im pretty sure the LS3 engines only came with the 58 right?

[Vega$69]

58 and yes im pretty sure the LS3 engines only came with the 58 right?

Yep. What ECU?

[Swain]

Yep. What ECU?

http://secure.ultracart.com/catalog/PSI/PCM-PROGRAMMING/LS-pcm-programming/PCM-1010.html

I'm thinking it's a fuel issue

[Vega$69]

Is the fuel pump mounted above or below the tank?

[dhutton]

How much gas did you put in the tank? I would recommend at least 5 gallons. If the pump is mounted high it may cause you problems. Most run in tank pumps....

Don

[Vega$69]

How much gas did you put in the tank? I would recommend at least 5 gallons. If the pump is mounted high it may cause you problems. Most run in tank pumps....

Don

And externals need to be mounted below the tank to gravity feed. The pumps are pushers not suckers

[Swain]

Lowered the fuel pump got it to run for a sec then back fires think the valves are maybe too tight

[XLexusTech]

Lowered the fuel pump got it to run for a sec then back fires think the valves are maybe too tight

Should have the mods change subject just to avoid any wirdness for psi conversion s

[Che70velle]

Lowered the fuel pump got it to run for a sec then back fires think the valves are maybe too tight

Jay, did you have the engine apart? Maybe a cam change? I've seen many people put too much preload on the lifters of a SBC, and it will back fire and not run every time, but I'm not sure it's possible to accomplish this with an LS platform, to that extent...having said that...you said earlier in the thread that you weren't getting spark. Can you verify spark and fuel?

[Vega$69]

Ls3 rockers are not adjustable. If a cam swap was done then measuring pushrod for proper length would be the prudent thing to do.

These are hydraulic rollers so unless they are way off it would not keep the motor from running

I'm trying

may just have to roll down to Cali

[Swain]

Ya that's true. Cam was never taken out. It's a crate engine with the 480 cam

I'll get back on it tomorrow.
Thanks for all the helpful hints

[Swain]

Car starts up found out why the car backfires. The rockers were off the valves all he way on a few cylinders.

Think we got it figured out

[Vince@Meanstreets]

Car starts up found out why the car backfires. The rockers were off the valves all he way on a few cylinders.

Think we got it figured out

Dang, Hecho en where?

[Swain]

Two rocker arms have bad bearing so in going to buy a new set and replace them all.

Anyone run roller rockers? Or should I stay with the stock style rocker arms with the Trunion kit?

[XLexusTech]

Two rocker arms have bad bearing so in going to buy a new set and replace them all.

Anyone run roller rockers? Or should I stay with the stock style rocker arms with the Trunion kit?

http://ls1tech.com/forums/generation-iv-external-engine/1679825-ls3-rocker-arms-ones-best.html

[Vince@Meanstreets]

Two rocker arms have bad bearing so in going to buy a new set and replace them all.

Anyone run roller rockers? Or should I stay with the stock style rocker arms with the Trunion kit?

Trunnion kit. we swap em on all ls

[71RS/SS396]

I would stay with the stock rockers in your case. We've seen failures with those too.

[dhutton]

Two rocker arms have bad bearing so in going to buy a new set and replace them all.

Anyone run roller rockers? Or should I stay with the stock style rocker arms with the Trunion kit?

So a brand new unfired GMPP crate engine had bad rocker arms right out of the box? That doesn't sound very encouraging..

Don

[Swain]

So a brand new unfired GMPP crate engine had bad rocker arms right out of the box? That doesn't sound very encouraging..

Don

The engine had 25-50 miles on it long story the engine was in a car that had a small fire. 1960 Chevy it was in caught fire but they got to it within a min or two so just the intake and other plastic parts were melted. The engine did have water in it for some time. Thinking now two lifters may be bad.

I'll order the Trunion kit anyway just to cross that out

[Swain]

could lifters feel spongy? Think they just need to build up pressure maybe from cranking the engine over and not starting all this time could of drained the oil?

Should I replace them dont really want to pull the heads

[Vince@Meanstreets]

The engine had 25-50 miles on it long story the engine was in a car that had a small fire. 1960 Chevy it was in caught fire but they got to it within a min or two so just the intake and other plastic parts were melted. The engine did have water in it for some time. Thinking now two lifters may be bad.

I'll order the Trunion kit anyway just to cross that out

:confused59:

[Vega$69]

The fire would have been helpful info to pass on when looking for help diagnosing the start up issue:headspin:

[XLexusTech]

The fire would have been helpful info to pass on when looking for help diagnosing the start up issue:headspin:


:innocent: :ohsnap: :ohsnap:

[dhutton]

could lifters feel spongy? Think they just need to build up pressure maybe from cranking the engine over and not starting all this time could of drained the oil?

Should I replace them dont really want to pull the heads

You should make sure you have good oil pressure before starting. LS motors can be difficult to prime. Remove the plugs, disable the ignition and fuel and crank til you have good oil pressure. This is quite important.

Don

[Swain]

Damn fix one this then another thing goes wrong.

My fuel pump wire lost power. Fuse is good relay is good. what the..............

[Vega$69]

Damn fix one this then another thing goes wrong.

My fuel pump wire lost power. Fuse is good relay is good. what the..............

PSI Harness. Fuel Pump relay gets 12V from the ECM when Ign is turned on.

So are you saying you don't have 12 on the wire that goes from the relay to the pump?

[Swain]

PSI Harness. Fuel Pump relay gets 12V from the ECM when Ign is turned on.

So are you saying you don't have 12 on the wire that goes from the relay to the pump?

No Power so its mailed back out to Gary @ PSI

He said he would get it fixed and set back to me. Ill get there soon

[rickpaw]

Before you send it back to PSI, just be aware that the ECU shuts off the power to the fuel pump after 5 s (I think) if the engine is not running. Not sure if you know that or not.

[Swain]

Before you send it back to PSI, just be aware that the ECU shuts off the power to the fuel pump after 5 s (I think) if the engine is not running. Not sure if you know that or not.

It use to do that now it does t have any power coming from the ECU.

[Swain]

Back at it....

ECU Re Programmed everything seems like it should run. It wants to start but just wont fire.

My fuel pressure is only at 50 PSI could that be too low?

[Vega$69]

Back at it....

ECU Re Programmed everything seems like it should run. It wants to start but just wont fire.

My fuel pressure is only at 50 PSI could that be too low?

It should start and run just fine with 50 PSI

[67Rally]

Back at it....

ECU Re Programmed everything seems like it should run. It wants to start but just wont fire.

My fuel pressure is only at 50 PSI could that be too low?

Make sure you have 12v going to red ignition wire with "key on & cranking".

The wire I fed it with had power with key key on only, but nothing when cranking. It would turn over, but not fire up. It's a fairly common issue (sorry if you have already checked this).

[Swain]

So my new Vaporworks tanks in. I hooked up a scanner to the car and its throwing a P0135 code. The scanner says Crank sensor but I changed it. Online forums says o2 sensor. Hmmmm

[Vega$69]

Does it start and run now?

Car will still run with the P0135 code. In fact it should start and run even if the O2 sensors are not installed.

[Swain]

Does it start and run now?

Car will still run with the P0135 code. In fact it should start and run even if the O2 sensors are not installed.

No start it wants to start it sounds like but nothing

[Vince@Meanstreets]

No start it wants to start it sounds like but nothing

po135 is the heater circuit....ASD relay controlled.

Have you called PSI again yet?

[Vince@Meanstreets]

Make sure you have 12v going to red ignition wire with "key on & cranking".

The wire I fed it with had power with key key on only, but nothing when cranking. It would turn over, but not fire up. It's a fairly common issue (sorry if you have already checked this).

So my new Vaporworks tanks in. I hooked up a scanner to the car and its throwing a P0135 code. The scanner says Crank sensor but I changed it. Online forums says o2 sensor. Hmmmm

J,

Did you check for this?

We add a relay to provide 12v to the ignition circuit during cranking. Also double check your power and ground circuits. Something ain't right.

[Swain]

J,

Did you check for this?

We add a relay to provide 12v to the ignition circuit during cranking. Also double check your power and ground circuits. Something ain't right.

I am going to check to check the injectors with a NOID light. It will fire for a split second. I think the ignition switch could be bad? Maybe its dropping too much while cranking?

[Vince@Meanstreets]

I am going to check to check the injectors with a NOID light. It will fire for a split second. I think the ignition switch could be bad? Maybe its dropping too much while cranking?

If it is the factory style switch in the dash it will provide zero voltage while cranking. This system ran 12v cranking voltage from the resistor bypass on the starter.

You can run a relay with a diode to use the purple starter wire as a signal to send 12v to the ignition circuit.


Vince

[Swain]

If it is the factory style switch in the dash it will provide zero voltage while cranking. This system ran 12v cranking voltage from the resistor bypass on the starter.

You can run a relay with a diode to use the purple starter wire as a signal to send 12v to the ignition circuit.


Vince


Thanks Vince,

I have been thinking about this a lot. I am going to try this tonight or tomorrow.

[Vega$69]

If it is the factory style switch in the dash it will provide zero voltage while cranking. This system ran 12v cranking voltage from the resistor bypass on the starter.

You can run a relay with a diode to use the purple starter wire as a signal to send 12v to the ignition circuit.


Vince

You don't need any additional relays or diodes.

I've done 5 LS swaps on 1st Gens all with factory ign switches. 3 GM Perf Harness, 1 Psi and 1 reworked GM take out harness.

LS ECM

You need 12v switched power to the PSI fuse box.

The ECM is powered up with ign 12v. When you turn the key on the ignition and fuel pump relays close.

When you hit start the purple wire provides 12v to the starter.

From PSI

NO-START
1. Red Ignition Wire (From back of Fuse/Relay Center) has 12-volts with the Key in the ON
position and CRANKING position. This cannot be stressed enough, most NO-START
conditions can be traced to this wiring issue.
2. Check that 2 Large Ring Terminals by Crank Sensor are connected to CONSTANT POWER.

Batt. Battery Positive (2 LARGE RING TERMINALS COVERED IN BLACK HEAT
SHRINK), These are often mistaken for ground wires because of the black heat shrink

[Swain]

Thanks for all the help. Soooo I think I know what's wrong the car will start for a second if it's been sitting for an hour or so. I think the injectors are clogged or not working. They were new injectors they were from a friend that works at Magnuson Superchargers. I think the were sitting for some time as the car smells like stale fuel. Either the injectors aren't getting power or the injectors are clogged. Testing that tomorrow. If all else fails I got a guy coming to look at it this Sunday.

You don't need any additional relays or diodes.

I've done 5 LS swaps on 1st Gens all with factory ign switches. 3 GM Perf Harness, 1 Psi and 1 reworked GM take out harness.

LS ECM

You need 12v switched power to the PSI fuse box.

The ECM is powered up with ign 12v. When you turn the key on the ignition and fuel pump relays close.

When you hit start the purple wire provides 12v to the starter.

From PSI

NO-START
1. Red Ignition Wire (From back of Fuse/Relay Center) has 12-volts with the Key in the ON
position and CRANKING position. This cannot be stressed enough, most NO-START
conditions can be traced to this wiring issue.
2. Check that 2 Large Ring Terminals by Crank Sensor are connected to CONSTANT POWER.

Batt. Battery Positive (2 LARGE RING TERMINALS COVERED IN BLACK HEAT
SHRINK), These are often mistaken for ground wires because of the black heat shrink

[Vince@Meanstreets]

You don't need any additional relays or diodes.

I've done 5 LS swaps on 1st Gens all with factory ign switches. 3 GM Perf Harness, 1 Psi and 1 reworked GM take out harness.

LS ECM

You need 12v switched power to the PSI fuse box.

The ECM is powered up with ign 12v. When you turn the key on the ignition and fuel pump relays close.

When you hit start the purple wire provides 12v to the starter.

From PSI

NO-START
1. Red Ignition Wire (From back of Fuse/Relay Center) has 12-volts with the Key in the ON
position and CRANKING position. This cannot be stressed enough, most NO-START
conditions can be traced to this wiring issue.
2. Check that 2 Large Ring Terminals by Crank Sensor are connected to CONSTANT POWER.

Batt. Battery Positive (2 LARGE RING TERMINALS COVERED IN BLACK HEAT
SHRINK), These are often mistaken for ground wires because of the black heat shrink

are talking about the PSI harness or the factory GM fuse panel?

I was thinking he might have those mixed up but the PCM is powering up from his description.

[Che70velle]

Jay, pull a spark plug. If it's wet, the injectors are firing. The noid light will help you in seeing if they are firing. You'll be amazed at how simple your problem was, once the car starts.

[Vega$69]

are talking about the PSI harness or the factory GM fuse panel?

I was thinking he might have those mixed up but the PCM is powering up from his description.

He said he has the PSI harness. Maybe injectors are clogged but to have all clogged would be a surprise to me.

Car had a engine fire which could have damaged them however as I read it he has different injectors in it now.

As always it's probably something simple like a loose ground.

A friend of mine had a problem with his LS and PSI setup cranking and not starting. Turned out where the 2 grounds bolt to the rear of the head the bolt was a touch too long and bottoming in the threads. The bolt was tight but the grounds were loose.

[Swain]

Hooked up a NOID light this AM. The light comes on then never comes back. Seems like the injectors only get a signal for a second then goes away. I have sent the ECU back twice. I have a guy coming over Sunday to hook it all up.



We have added grounds everywhere. Cleaned off metal so its a good contact.

[Vega$69]

Ckeck the ignition relay on the psi fuse box.

Switch it with the fuel pump relay and see if the noid light works.

Pull the relay and check that you have 12v to it key on and when cranking.

[Swain]

Ckeck the ignition relay on the psi fuse box.

Switch it with the fuel pump relay and see if the noid light works.

Pull the relay and check that you have 12v to it key on and when cranking.

Thanks for all the help. I just sent my Dad a text for him to try it. I will keep you posted.

[Swain]

She runsssssssssssssssss

Instagram. Jayswiz

[cpd004]

She runsssssssssssssssss

Instagram. Jayswiz

Congrats Jay.

[XLexusTech]

What was it?

[Vega$69]

Come on man. What was it?

Inquiring minds want to know.

[Swain]

Come on man. What was it?

Inquiring minds want to know.

Still gotta figure it out. I tried a little starter fluid and it fired right up. It won't start unless you spray just a tad. So maybe it needs a little start up tune

[Swain]

714-345-3875 text if ya wanna here a short clip

[dhutton]

Sounds like you do not have proper ECM voltage while cranking. Have you measured the voltage with a meter while cranking etc?

Don

[cpd004]

Hooked up a NOID light this AM. The light comes on then never comes back. Seems like the injectors only get a signal for a second then goes away. I have sent the ECU back twice. I have a guy coming over Sunday to hook it all up.



We have added grounds everywhere. Cleaned off metal so its a good contact.

My Ls3 does this. When I initially turn the key to run, the noid light flashes for like a 1/2 second. At crank it doesn't flash, but when the motor fires, it begins to flash constantly. I have no starting issues and am running an E38 with Corvette regulator (return less).

[Vega$69]

Corvette regulator (return less).

Corvette reg does have return to tank at the regulator.

[cpd004]

Corvette reg does have return to tank at the regulator.

I meant returnless at the rail...thanks!

[Vega$69]

I meant returnless at the rail...thanks!

Yep. Much better way then to return fuel from the rails that has been heated as it passes through the engine bay.

[badazz81z28]

I know I'm super late to this party, but I don't have my wires for the TCC pedal hooked up either. Runs just fine. Like mentioned, the #1 reason for not firing is the constant power to the ECM while cranking.

I ran my ECM power from the HEI power wire.

[ItDoRun]

You don't need any additional relays or diodes.

I've done 5 LS swaps on 1st Gens all with factory ign switches. 3 GM Perf Harness, 1 Psi and 1 reworked GM take out harness.

LS ECM

You need 12v switched power to the PSI fuse box.

The ECM is powered up with ign 12v. When you turn the key on the ignition and fuel pump relays close.

When you hit start the purple wire provides 12v to the starter.

From PSI

NO-START
1. Red Ignition Wire (From back of Fuse/Relay Center) has 12-volts with the Key in the ON
position and CRANKING position. This cannot be stressed enough, most NO-START
conditions can be traced to this wiring issue.
2. Check that 2 Large Ring Terminals by Crank Sensor are connected to CONSTANT POWER.

Batt. Battery Positive (2 LARGE RING TERMINALS COVERED IN BLACK HEAT
SHRINK), These are often mistaken for ground wires because of the black heat shrink

You hit the nail on the head here! I just started mine for the first time this evening. Got everything wired up (harness and ECM from PSI as well). Wasn't getting juice to the fuel pump wire (87 slot on relay). Come to find out I had tied those two Battery Positive wires to the block as grounds not to the starter as required. Car starts and runs now but won't idle. Not hijacking this thread so I'll start my own but am subscribed to this one.

[cjsgarage]

That stinking starter lug wire. One of the reasons I don't like the PSI harness.

[ItDoRun]

That stinking starter lug wire. One of the reasons I don't like the PSI harness.

It would help if the wire was red! HOWEVER.....my fault for not reading the instructions clearly.