Need urgent help with a 96 K1500 SIlverado

[tundrawolf]

Hi,


So I got a salvage title truck, it is going to be my work truck, I have a tremendous opportunity to go work in another town but I NEED this truck!

I have spent the last few months making it derivable, including a windshield I put in myself, new glass, new bulbs/grill/etc, it always started right up and drove just fine.

I had to do some diagnostics on the ignition system ()Found out bad connector to coil which I repaired and was fine) and I exposed bare wiring, the white, and white/black stripe wires going to the ignition module, I forgot to tape them back up, and on it's maiden voyage I got 40 feet before they touched, and the motor stalled...

I did the usual; checks, it's getting +12V at the pink wire, but no ground at the white/ black stripe wire, but ground at the black wire. According to the tutorial the white/black stripe should be grounded so I "Made" on, well the tutorial is wrong, that is the signal wire, it blew the ECU fuse...

I went to a junk yard and got an ECU that fits, and a new crank sensor, the crank sensor fires and checks out OK< but the ECU isn't sending any signal to the module. Do i need to re learn for this new ECU? Or get another ECU? The crank sensor pulses and checks out fine, so it's the ECU or maybe I fried the ignition module? I had two ignition modules, neither appear to pulse at the white wire.

So is there an ECU "Learn" that has to go on? Some sort of procedure? The inspection is only held once a week and it is tomorrow, and this new job needs me NOW. I am trying to stay calm but this is really stressful.

 

[kennythewelder]

I'm sure you have already looked through these, but here is a link anyway.
https://www.youtube.com/results?search_query=96+chevy+ecm

 

[tundrawolf]

I'm sure you have already looked through these, but here is a link anyway.
https://www.youtube.com/results?search_query=96+chevy+ecm

SO I went back and got the "old" ECM that was supplied with the truck, and I grabbed the ignition module from another truck, I installed both things (After verifying the crank sensor was pulsating when the crank was turning), and it fired right up. You were right, the old ECM wasn't broken or damaged, even though I grounded the white/black wire myself, thinking it needed a ground, according to an erroneous tutorial I read online. i guess the fuse saved the ECM because it blew, but the ECM was fine,. I drove it around yesterday and got it inspected registered.

It has a strange intermittent stalling issue that has been around since I got it... If I change ignition coils the problem goes away, then I have to switch back to the original coil when it fails to start... Until ti fails to start then I go back to the back up coil... I am starting to think that the high voltage wire to the distributor builds up pressure in the boot and pushes itself so far upwards that the spark can no longer travel up that high... I already rebuilt the delphi connector and spliced it in so I know that is good, it's not the connector.

But anyway thanks for your help, without your help I would still probably be trying to get the other ECM to work, and probably not having much lucky... Those ECMs are tough...

 

[kennythewelder]

Glad I could help.