[ima hustler]

Car will not start because my injectors are not firing. I did a noid light test and got nothing. With the ignition on I have power to the injectors but no ground. While cranking I have the same problem. What could cause this? any ideas.

 

[Mr pogo]

any fault codes?

 

[ima hustler]

No, the car has not ran for two years. Ignition is good, I have a strong spark. With starting fluid the car starts right up and then dies. I had 0 psi at the fuel rails so I replaced the fuel pump, the sending unit, and installed a new FPR. I now have have 43 psi at the rails but for some reason the injectors will not work. I have checked all fuses with a test light I have determined I have power at the injectors but no ground. PCM issue? I hope not..

 

[BigB9000]

Well, they are constant +12, the ground is the trigger.

It would be hard to test for this, as the 1/32 of a second ground would be hard to identify.
Chances are, they are working.

I would look more into a opti or ICM problem- whatever triggers the injectors.
Or PCM.

 

[Mr pogo]

he used a noid which will show the pulses.
the opti signals are needed to tell the pcm when to fire off each injector.
I would check the fsm for causes, it sounds pcm related.
and when I mentioned codes, was a scanner used and is the pcm communicating?

 

[4DoorSS]

I would also lean toward the PCM as others have mentioned. But if u have no spare to plugin and think it might be ground related, check the ground wires at the Cylinder head near the coil/ICM module.

I don't have a wiring diagram in front of me but would suspect the FI's are grounded on that area. There is about 3 o4 wires/circuits that get grounded there. Pull them off and make sure there is a good connection with no crude there and use some dieletric grease when putting back together.

 

[94MI9C1]

The grounds are a good call. The ones feeding the PCM is where I would start.

 

[ima hustler]

Thanks for the input guys. I wish I had a spare pcm, I would just switch them and see if thats the problem. O well, I guess I'm going ground hunting tomorrow and I will repost back with what happens.

 

[ima hustler]

So today I checked all of the grounds. The one by the ignition coil wasent to bad but i went ahead and cleaned the heck out of them, along with other ground points. Still not running and doing the same thing.

I took the opti spark wire harness off and checked the resistance of the wires and they seem to be functional. I believe either the opti is not sending the signal to the pcm or the pcm is getting the signal not grounding out the injectors for some reason. Is there anyway to test this?

 

[94MI9C1]

If you are getting spark, the injectors should be firing, the pcm uses the same signal from the opti to trigger the ignition as it does for the injectors. I will get you the troubleshooting link when I get back to my office.

Edit: here you go http://www.mainstreamtopics.com/forums/topic/78-lt1-no-start-diagnostic/

 

[cuban1990delta]

If you are getting spark, the injectors should be firing, the pcm uses the same signal from the opti to trigger the ignition as it does for the injectors. I will get you the troubleshooting link when I get back to my office. Edit: here you go http://www.mainstreamtopics.com/forums/topic/78-lt1-no-start-diagnostic/

What was it