2.8 Fuel injectors no pulse (Page 1/1)
DeepGoat MAY 21, 10:57 PM
First post, been a long time since I’ve been on here or had a Fiero for that matter. Looking for some help!

Just bought an 88 GT. Was hunting a high idle and replaced the vacuum lines, gaskets, egr tube, reman injectors etc etc. Put it all back together and now it will not start. Figured out I’m not getting fuel.

Have 40psi fuel pressure at key on. Fuel pump primes fine. Bump the key and fuel pump will kick on again as it should. Check engine light is on on key on so the pcm is getting power. Tach bounces upon cranking.

With a test light (and multimeter) I’m getting getting power to the flat 6 injector connector harness. The ecm isn’t grounding the injectors. Thinking it’s an EST signal problem, I replaced the ICM and coil at that point just being hopeful. Checked pickup coil resistance as fine. Made sure all connectors are in good shape, no pushed in pins, etc. Still nothing.

So I followed an old post here

https://www.fiero.nl/forum/...060811-2-069743.html

Using Jazzman’s walkthrough, everything worked/tested out up until the point of probing the wires at the ecm. Since the thread is old and now without pictures, I’m assuming the wires to probe at the ecm are an ignition hot and then ground to one of the 4 injector wires in C15 or D14,15,16. Doing this and cranking produces no light. Verified light works on hot to ecm ground pin D1.

But here is the kicker, another post I read said to test the ecms ability to make that ground by mimicking the EST signal. By jumping the 5v source on the TPS plug to the R terminal of the ICM plug with the key on. In doing so, fuel pump kicked on and injectors all clicked.

So is my ecm fried? Or am I overlooking something completely simple? Getting to be at my wits end here. Ran fine, aside from idling at like 2500 prior to opening it up!

[This message has been edited by DeepGoat (edited 05-21-2021).]

phonedawgz MAY 22, 04:05 AM
During cranking the tach should not jump around. It should rise to 200 and then fall back to zero after cranking.
DeepGoat MAY 22, 11:05 AM

quote
Originally posted by phonedawgz:

During cranking the tach should not jump around. It should rise to 200 and then fall back to zero after cranking.



I think worded it funny sorry. By tach bounce on cranking I mean it moves to 200ish rpm with +-20 or so while cranking it. Meaning the needle fluctuates a tad. Which from what I gathered is normal?
Notorio OCT 24, 05:10 PM
Deep, did you ever figure this out??
Dennis LaGrua OCT 28, 09:42 PM
First step would be the check the fuse.