Mayt13

1989 L98 w/ 700r4 all stock

Im totally stumped!

Car cranks, but doesn't fire. No injector pulse, no fuel pressure at rail. Pump works since jumping port G on the ALDL pressurizes rail, plus it a brand new pump. Checked all fuses on the fuse block, they're good. Checked under hood ECM fuse, its good. Had a spare ecm, swapped it, still nothing.

How do I text/Fix this? The car has been parked almost a year now...



EDIT:
BTW what has to be hooked up under the dash for the car to fire? I have a resistor bypass in the vats connector, and am cranking directly from the ignition switch, most of the steering column wires are disconnected, although I believe they control turn signals and the like.

What does the ECM require to fire the injectors? I assume it needs power and a reference pulse from the distributors module. In the past I also heard something about the oil pressure switch, could this be contributing to my problem?

antares57

iTrader: (8)

Update your profile to let us know at least year, model, and engine type. We can only guess at what the problem is. Is the fuel pump priming when you turn the key to run? Have you checked the fuel pump fuse on the inside passenger fender wall?

Mayt13

Not Priming, but it does pressurize rail when jumped from the ALDL. Its a '89 TPI 350 Camaro BTW, sorry for not mentioning.

Mayt13

On another note, Im not showing a code 12 when I put the key to "on" with an OBDI scanner, which is making me suspect ECM has no power. What pin is ECM power so I can check for 12V?

Also, Just replaced the distributor since the Since it failed test 6, as seen here. The little magnet on the distributor neck want producing enough current. Thought it was the problem.
[ICM tests"]http://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/distributor-mounted-icm-tests-6[/URL]

looking to the underhood ECM fuse. With Key turned to "on" no voltage across it. Took test light and look for power, neither showed it (even lower than where the wire had some a crappy crimp connecter). I am again stumped.

Literally going insane, please help.

Mayt13

Summary
-Cranks but doest start
-No Injector pulse
-Fuel pump does not prime, but turns on if ALDL is jumped from port G
checked at rail, shows pressure when jumped
-No voltage across underhood ECM fuse, no power from lines.
-No code 12 w/ OBDI scanner
-New distributor, to eliminate ICM as possible issue

How can there be no voltage at the underhood ECM fuse? Where does that line even go?
What PIN on the ECM connector do I check to see If I'm getting power?


EDIT:
What PIN on the ECM connector do I check to see If I'm getting power? (answered)

Quote:

There are two power feeds to the ECM: battery +, (orange wire) and IGN+ (pink/black)

from here

Mayt13

All colored ones have power when key is "on" despite underhood fuse being disconnected. Purple ones "clicked" when I gave them ground so I'm assuming they connect to relays.

This was done with a simple test light connected to battery ground.

tom3

I'd start at those cut wires on the steering column. Power to switch and power out?

jmd

iTrader: (4)

All stock?

You should be using the factory service manual to diagnose step-by-step. It will not lead you down paths of guesswork and parts cannon firing. Frankly, an 86 through 89 manual would work.

Mayt13

What? When you say cut, do you mean disconnected? I hooked them up when testing before, no difference all steering column wires to allow it to control blinkers and stuff. I'm cranking directly from the ignition switch, none of those would affect drp.

Mayt13

I have yet to see a factory service guide with good trouble shooting guides, generally say "fix the problem". But I will get one anyway. I need to figure this out.

bigal55

iTrader: (1)

Here's a diagram from AustinThirdgen.org. Get the fuel pump working correctly first, it might lead you to the no firing solution.