HELP! NO INJECTOR PULSE,...non running 96 suburban tried everything

[exp500]

Pin #28 purple on Blue C1 connector- Crank sensor
Pin 31 Yellow On BlueC1 connector- Crank sensor
Pin 9 white on Grey C3 to ICM Pulse wire
pin 17 Black/white on Gray C3- System ground
pin 18 Black/white on gray C3- ground
Connector end views. Sorry this is from my notes on a 96 tahoe, all Ive got.

 

[corbin dallas]

Check for spark, check for signal from crank sensor.

it runs on carb cleaner. has everything it needs to run,..just NO INJECTOR PULSE.

 

[corbin dallas]

Pin #28 purple on Blue C1 connector- Crank sensor
Pin 31 Yellow On BlueC1 connector- Crank sensor
Pin 9 white on Grey C3 to ICM Pulse wire
pin 17 Black/white on Gray C3- System ground
pin 18 Black/white on gray C3- ground
Connector end views. Sorry this is from my notes on a 96 tahoe, all Ive got.

thanks,..just need to figure out why there isnt a ground signal from the ecu.

 

[exp500]

If you run the test for ICM, that will verify crank position sensor signal on that split. One runs injection thru computer, one runs ICM. Verify signals.
IF computer shows ground and injectors will not ground then it is in injector assy.
Thats why I gave you what I had for diagrams.
It would help you to read thru the service manual.

 

[corbin dallas]

If you run the test for ICM, that will verify crank position sensor signal on that split. One runs injection thru computer, one runs ICM. Verify signals.
IF computer shows ground and injectors will not ground then it is in injector assy.
Thats why I gave you what I had for diagrams.
It would help you to read thru the service manual.

hey there. please forgive my nativity on using this site. having some difficulty navigating the responses,...anyway im assuming I have posted this question in the right place. you said in one of your replies to use the "gmt400" not sure what that means. im thinking of writing a step by step background I have done to better explain where I am at now. in response to your above reply I dont know the icm test, but replaced the whole setup(icm/coil) with a known good one. still no start,..I also replaced the crank sensor with a known good one-still no start. of course that doesnt mean I know for sure that there is signal going where it is supposed to do,..but should have changed something if the originals were bad,...just looking for some advice from you as to how I should move forward. start a new thread? or stay with this one? so far i have had no change in solving the problem.

 

[corbin dallas]

If you run the test for ICM, that will verify crank position sensor signal on that split. One runs injection thru computer, one runs ICM. Verify signals.
IF computer shows ground and injectors will not ground then it is in injector assy.
Thats why I gave you what I had for diagrams.
It would help you to read thru the service manual.

im wondering if its actually my spider injection. i had a strong smell of fuel mostly after shut off,..that came and went. before all this happened,..I had redone the upper and lower intake gaskets. ran fine for awhile after that. just before all this happened,..I took off the upper manifold and replaced the fuel pressure regulator. then,..more misfire, fuel smell and stumbling,..then,...off. truck has about 200k. original spider system. i hate to throw more parts at this but maybe its time to replace the spider especially since they have upgraded that system,..and its only about $130. what do you think? ive replaced everything else,..lol

 

[exp500]

Corbin, stay on this thread please. This is For GMT 400 Model Series
Without testing, you can throw alot of parts at it and in the end never know what failed, or still have a problem. Look around for a Factory manual PDF or AllData subscription. $15-60.

Your symtoms are a failed ground at the computer- That could be under the dash even. Or a Failed wire feeding crank sensor signal to computer.Or a Anti theft that maybe was installed before you. Or Failed ground thru harness from injectors to computer.
One guy here had two big oval injector body gaskets tnstalled and his plug wouldn't connect the pins.
You might get lucky and bump the right thing the right way and have it run, but chances are you will have to find it by eliminating possibilities by checking signals. Wiring Diagrams for a 96 sub will show what wires are grounds and where also. That would be my first step. Next would be Noid light or 194 bulb testing each injector circuit. Then Signal tests for CPS. Please be specific when describing tests performed and results. Good luck and keep posting. We are here to help .

 

[corbin dallas]

The problem is I dont know how to do any of these tests. i have all the tools and diagrams but not sure how to proceed. right now I am removing the upper intake. i didnt have a good fit where the pulg came all the way up for the wiring harness to plug into even though it snapped into place,..it was still recessed about an 1/8 of an inch. i will use a better oval gasket this time and I am going to remove and upgrade the spider while I am at it

 

[exp500]

All you have to do is ask. We will try to walk you thru the testing.
The Factory manual has a very complete troubleshooting guide even for chasing codes. It will explain the how it works part so we here can focus more on how to do the factory tests with a multimeter or another way. Consider it a $15 dollar educational expense as nobody here has offered up the wiring diagrams for a 96. Maybe you could be the first.

Grease the outside of the big oval gasket, and inside intake before you drop upper intake on. Make sure the bracket is not bent.

Something very handy when doing these tests are alligator clip wires, buy a set for $5 amazon or harbor freight.
Test output of CPS set meter to ACVolts connect leads crank engine. purple +
Test signal to ICM set meter to ACV connect to white wire pin+ ground- lead crank engine or connect 194 bulb to white wire lead connect other bulb lead to ground.
Set meter to ohms, - term on battery, + term to another ground location, like the strap at firewall back of intake or head. Or the computer case.
Good luck with injectors/intake. Keep posting.

 

[BG1988]

hello. i will try to give you overview,..need some help. my 96 suburban with stock vortec 5.7 crab injection. truck ran fine,..then started to skip and run rough especially after startup warm or cold. then smooth out after 1 mile. hard code of p01345 crank/cam correlation. also was running 28degrees timing and had misfire codes, mass air meter out of range, o2 sensor and lean codes. so rplaced mass air. no change, replaced distributor. double checked installation and made sure no slack in timing chain-no change. replaced crank sensor,..no change, replaced fuel punmp,..no change. then one day it sputtered and stumbled up the driveway and shut off. never ran again. checked injector pulse and nothing(not grounding),..got new computer and sent out to reprogram,..stil no run and no injector pulse. HELP!!!!!!!

you did check the injector with a tester light correct?