intermediate crank signal - Lateral-g Forums

awesometool · #1 09-19-2009, 04:32 PM

I'm having trouble with intermediate crank signal so when I turn engine over the rpms are at 0 but when I let off the key it jumps up then right back to 0. It will not start with no crank signal. I have tried changing starter, disconnected alternator, pull one fuse at a time, reground battery to block and frame, 00 starter wire, disconnected the dfu's, disconnected the fans, tec unit is direct batttery power and grounded well.

I do not have and electric water pump and the crank wire is well insulated. If the spark plugs are removed it has a perfect crank signal. I done working on it for today and I try again tommorrow. Any help would be appreciated.

**camcojb** · #2 09-19-2009, 04:56 PM

my initial thought was your switched 12 volt wire to the ECU (every one I've worked on has one, not sure on the Electromotive) does not have 12 volts when cranking. Needs to be the ignition fuse or similar, many have twelve volts with the key on, but not when cranking. But then you said it has a signal with the plugs out, so that makes no sense.

I still would double check this switched 12 volts wire, even going to battery voltage if need be tio make sure that is not the cause.

Jody

awesometool · #3 09-19-2009, 05:27 PM

thanks, I did run a direct to the battery for the acc turn on power supply to test it. I thought it might be cutting out but it did not help.

**camcojb** · #4 09-19-2009, 05:32 PM

Quote:

Originally Posted by awesometool

thanks, I did run a direct to the battery for the acc turn on power supply to test it. I thought it might be cutting out but it did not help.

what is your cranking voltage? If it's dropping below 11-11.5 volts that can cause all kinds of issues with aftermarket efi. Have you tried jumping it to start, or a different battery?

Jody

awesometool · #5 09-19-2009, 06:21 PM

It does not drop that much. I also used the 70 amp stinger power supply that is for the radio it did not change.

**camcojb** · #6 09-19-2009, 07:07 PM

Quote:

Originally Posted by awesometool

It does not drop that much. I also used the 70 amp stinger power supply that is for the radio it did not change.

your efi config is set for the correct tooth count on the crank wheel? I had one set for 58X and my early LS2 is 24X, no crank signal. This is for the LS engine. What engine/ignition are you running?

awesometool · #7 09-20-2009, 05:22 AM

It is a tec gt and 572. The crank is 58x that the gt requires. I'm going to supply power to the gt and ignition switch only then check it. I will also try jumping from my truck like you said.

wedged · #8 09-20-2009, 07:28 AM

Quote:

Originally Posted by awesometool

I will also try jumping from my truck like you said.

+1. sounds like battery voltage is dropping too much while cranking. I've had this happen with MSD ignitions. Engine "sounds" like it's cranking fast enough, but the voltage is too low to make the MSD spark. Hook up a jumper box and it fires right up.

awesometool · #9 09-20-2009, 03:51 PM

you guys where correct I checked the voltage at the battery in the past but it is low now when cranking and the my tec software is showing it drop to 10.5 but it bounces around 10.5 and 12.6 fast once it stays over 11.75 for a second while cranking there is crank signal. If it is on the 55amp start booster and gets up to 14.6 volts it will give a crank signal one second after I turn the key but only three times then it has to get back to 14.6 to get signal again. I have all the fuses out and a new optima deep cycle 870amp battery today. After looking at the trunk mounted battery it has a 0 cable so I added a 2 and added a second but it showed no difference. This is a hard one to solve

**camcojb** · #10 09-20-2009, 07:23 PM

Quote:

Originally Posted by awesometool

you guys where correct I checked the voltage at the battery in the past but it is low now when cranking and the my tec software is showing it drop to 10.5 but it bounces around 10.5 and 12.6 fast once it stays over 11.75 for a second while cranking there is crank signal. If it is on the 55amp start booster and gets up to 14.6 volts it will give a crank signal one second after I turn the key but only three times then it has to get back to 14.6 to get signal again. I have all the fuses out and a new optima deep cycle 870amp battery today. After looking at the trunk mounted battery it has a 0 cable so I added a 2 and added a second but it showed no difference. This is a hard one to solve

maybe give Electromotive a call. Your voltage with the charger on should be good enough to start the car. Many efi systems have voltage vs injector pulse tables to compensate for lower voltage and lower fuel pressure with the lower voltage, but that still shouldn't affect the crank signal.

Jody