1988 - 1998 (GMT400) Section for all discussion related to the 1987-1998 Chevrolet and GMC trucks.

1997 Chevy K2500 injectors not firing

Old Apr 25, 2020 | 12:36 PM
  #11  
Gumby22's Avatar
CF Veteran
10 Year Member
 
Joined: May 2011
Posts: 1,578
Likes: 302
From: Central Iowa
Default

Have you checked for a pulse signal using a noid light at the injector connector?

Reading back through the thread, it sounds like the *assumption* that the ECM isn’t pulsing the injectors has been made, but no actual testing has been done to confirm that.

If the noid light doesn’t show a signal at the connector (make sure to check one injector on each side as the 12v power feeds split into 2 groups before the connector), back probe the same pins at the ECM and rig the noid light. If there’s a pulse signal while back probing, there’s a problem with the wiring harness. If no signal while back probing, I’d verify all the power and ground feeds to the ECM are good before continuing to chase and replace anything else.

Below are the individual circuit pin outs for the injectors at the ECM. Note that injector 8 is the only one on connector 1 and the rest are on connector 2.
Reply
Old Apr 25, 2020 | 12:37 PM
  #12  
Gumby22's Avatar
CF Veteran
10 Year Member
 
Joined: May 2011
Posts: 1,578
Likes: 302
From: Central Iowa
Default



Reply
Old Apr 25, 2020 | 1:02 PM
  #13  
Rednucleus's Avatar
CF Addict
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 2,326
Likes: 307
From: Marysville, WA
Default

So for my 93 5.7 I am on my 3rd ICM in 350k miles; each time it failed motor would crank but injectors would not pulse. I could keep it running by adding gas down the throttle body. I have had both sudden failure & intermittent no runs. I misread, thought that had already been changed.
Reply
Old Apr 26, 2020 | 7:49 PM
  #14  
Kawabuggy's Avatar
CF Beginner
 
Joined: Dec 2016
Posts: 12
Likes: 2
Default

You say the CMP (Cam position sensor) has been replaced.. Did you use a scanner to install the distributor, and/or "time" the engine? It is absolutely essential that the distributor be timed using a scanner. You have to set it to "0" degrees using the scanner so that the ECM can then control the timing internally. I don't see any mention of how you installed, or timed, the distributor, or CMP.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
zbeamanx2
Tracker
14
Dec 20, 2018 10:32 PM
Nicholas Cunningham
Caprice
4
Oct 20, 2017 10:15 PM
Bob1945
Beretta, Corsica, & pre-1995 Lumina
1
Dec 23, 2012 1:43 PM
chris z
Silverado, Sierra & Fullsize Pick-ups
6
Sep 2, 2010 12:57 AM
onsite
Tahoe & Suburban
1
May 8, 2008 11:31 AM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 10:13 AM.