Hello everyone,

I'm trying to diagnose a 1351 code on my Blazer and a 'no start'. The Diagnostic says to check VCM terminal C3 pin 9 and C4 pin 18 to see if they backed out.

There is no pin 9 on the C3 PCM Connector.

The wire from the Ignition Control Module instead goes to pin 8 on the PCM, connector C3.

It's a 1996 Chevy Blazer 2wd, W vin. In fact many of my PCM pins don't come close to what this link shows:

Part 3 -4.3L, 5.0L, 5.7L GM PCM Connector Pin Outs

Did General Motors wire my Blazer wrong at the factory? Please help!

 

Not sure what flow chart you're using, but try this one. It's the flow chart directly from the "dealer issue" factory shop manual for DTC P1351:
https://blazerforum.com/forum/diagno...plained-35134/

 

That one also mentions PCM connector C3, pin 9.

I have nothing in pin 9 on connector C3 of the PCM.

 

96-97 use different PCMs than the 98+ so the wiring will be different. I all of the DTCs that are posted show wiring info for the 98+.

 

Thanks,

I'll subscribe to All Data and see if I can buy the PCM pinout for a 1996. What an electrical nightmare!

 

Remove the coil wire from the distributor cap, slide the boot back to expose the terminal and hold it ~1/2" away from ground, attempt to start the engine, do you have spark?

 

Yes,

There is nothing wrong with the spark system. It fires fine. Runs fine on carb cleaner.

Computer opens injectors and fires a couple cylinders then shuts everything down and sets the 1351.

Injectors won't re-open unless 1351 code is cleared. Then process starts from beginning.

ICM replaced along with everything else in the entire ignition system. New AC Declo fuel pump, 60psi. New injector spider. Every single sensor on the motor replaced exept knock sensor.

 

Clear all DTC's from memory. Unplug the injector harness at the injector housing. Crank the engine for ~15 seconds and see if P1351 is set in memory. Post your results.

 

I found my PCM pinout. There is a thread here about the 1995 "PCM-a", and my 96 has the same pinout as that late 95. Thanks blazer forum.

The Internet told me to count pins the wrong direction, pin 9 in the other direction is the ICM signal wire. I now have it chugging like a tractor while cranking, not quite getting enough fuel to really go. But enough fuel now that while cranking I'm not getting the 1351 anymore.

Ground wire to ICM was bad and ignition switch were bad.

Now need to find why I can't get enough fuel to run. 60psi fuel pressure. New mas, iac, tps, fuel pump, ignition switch, cap/rotor/wires/plugs, crank sensor, PCM, ICM, fuel filter, spider.

Almost got her. Tried unplugging mas, o2 sensors, took the 1st o2 out in case the cat was plugged.....still not quite enough fuel to idle. Map putting out @ 4 volts prior to crank, should be good.

 

tried this on my 95 with no start and 1351 still is there and also a 1442 now!