EFI Puzzler

[parsonsj]

Yeah, it fires with a "burst" now, rather than a sag. I think a little boost to the fuel might just get it started a half-beat quicker. Then I may try to lower the IAC a bit, but I'm trying to only do one thing at a time.

Part of this problem was because I originally wired the IAC backwards (I had the wrong pinouts), and so the original tuner (not Mike Norris) tried to tune for easy starts with no IAC. I got the IAC working a few weeks later, and now it's time to get the start tuned right.

The new owner should have a car that lights right off and goes anywhere, lol.

jp

[camcojb]

Originally Posted by parsonsj

The new owner should have a car that lights right off and goes anywhere, lol.

jp

that is definitely the idea............... Congrats on your progress.

Jody

[Van B]

Originally Posted by parsonsj

The new owner should have a car that lights right off and goes anywhere, lol.
jp

Anything brewing on finding a new owner? I was going to make a smart comment about getting it right for me, but so far, no bags of money from the sky.

[parsonsj]

No... nothing brewing. Sigh.

My next project seems as far away as ever.

jp

[awr68]

Well if you're bored You can always come help assemble mine!! All the fun without writing all the checks!

You'll find an owner! Good to hear you are figuring out the starting issue!

[parsonsj]

Today's update: I sorted out the sync signal from the cam. The firing order is 18726543, with the cam sync signal preceding cylinder 5.

Now when I retard timing on cylinder 1, it actually retards timing on cylinder 1, lol.

Today's cold start was more of a sag, even though I didn't make any changes to the cranking fuel or IAC. Today's change was to change the run/crank rpm number to 150 (from 400), and to have it start the fuel enrichment decay at 6 revolutions rather than 12.

I'll have another go at it tomorrow.

jp

[parsonsj]

Recently I put one of Norris' catch cans on the car and went back to the factory PCV. (my car was sucking big quantities of oil out of the crankcase with the racing PCV setup). One lesson there.

I also replaced all my Russell hose with hardline and Earl's hose. Another lesson there.

I also removed the stereo as I'm working on packaging A/C. A third lesson there.

Anyway, with those changes, and with no change at all to the EFI tune, the car starts way better. 2 seconds max. It fires with a burst, then quickly drops to a fast idle, then a normal idle as the engine warms up. It's perfect.

Theories:
1. The stereo was causing a big voltage drop, causing the XFI to reset.
2. My plugs were coated in oil, and kept the engine from firing easily.
3. My car likes playing jokes on me.
4. I'm going insane.

jp

[chevyIIpost]

Don't forget Murphy! He is a real a$$ and loves to invite all his family over to jack with you causing questions to your own sanity. I have meet a few of his other family members as I am certain everyone here has. I believe he has a half brother named "Interferance". A close cousin "Clarence" that rarely shows up when you need him.

[sacarguy]

lower you iac at crank for cold temps and raise your low temp cranking fuel up ..


also is your pump wired up to prime when you key on or is it just constant after sitting for a decent amount of time without a priming pump this can happen as you lose fuel preasure in the rail.

leaning out

2 things
1 do you have the wide band setup so you are in closed loop .. your raising the fuel preasure and can be fatenting it up causing the ecu to start corecting the other way.
2 are you sure your fuel pump can handle the load of the higher preasure without losing a ton of volume.

[parsonsj]

Originally Posted by sacarguy

lower you iac at crank for cold temps and raise your low temp cranking fuel up ..


also is your pump wired up to prime when you key on or is it just constant after sitting for a decent amount of time without a priming pump this can happen as you lose fuel preasure in the rail.

leaning out

2 things
1 do you have the wide band setup so you are in closed loop .. your raising the fuel preasure and can be fatenting it up causing the ecu to start corecting the other way.
2 are you sure your fuel pump can handle the load of the higher preasure without losing a ton of volume.

I think Mike Norris finally got the cold start figured out. And with my latest changes it starts faster than my truck! Amazing, but true.

But to answer your questions:

1. Yes, I have a priming sequence. At key "on" the pump primes for 10s, and I get fuel pressure after about 4s. I then start the car. It starts immediately now!

2. I'm using an Aeromotive A1000. I'm sure it can deal with volume at higher pressure.

3. I've got a wideband and run closed loop after the engine warms up.

jp