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-   1992-1999 (https://www.gmforum.com/1992-1999-91/)
-   -   '93 Bonne, cranks but not start (https://www.gmforum.com/1992-1999-91/93-bonne-cranks-but-not-start-287103/)

Mike 01-05-2010 01:58 PM

Quote:

Originally Posted by BillBoost37 (Post 1417133)
Hwy Elvis Jr.. he said the fuse was fine. :)

With the fuse in place and the key on. Test for power at the fuel injector connectors. If you have power, then it's the pcm not toggling the ground that is causing you not to have fuel.

BTW.. I was on the side of the road and swore I had fuel because of the same reasons you did. That tuaght me never to trust fuel at the rail mean that fuel was also flowing past the injectors. :thumbup2

He said he visually checked it. How many times have you pulled a fuse thinking it was good, but discovered by testing it, was no good? I have! That's what I gandered when he said he got it to restart because he replaced the fuse. :D

kparrent 01-05-2010 02:30 PM

My 94 was cranking but not turning over this weekend.. turned out to be the crankshaft position sensor. I would say start with pulling the ICM and having it tested at Autozone. Free and eliminates that possibility. Check primary and secondary ignition coil resistances.

If you disconnect the camshaft sensor and it starts, then it is probably an IAC issue if I'm correct. We'll let one of these more experienced guys confirm that.

elmerfud 01-05-2010 02:39 PM

Sorry for the delay in my continued testing, thank you for your assistance so far. Car is outside and temps have been around 5f so when the sun goes down it's really cold.

Anyway, yes, I did test the fuse (after I replaced it) and it was good. Today, going on the assumption of a short to the injectors I pulled back the loom on the wiring harness and noticed a couple of splices. Tested continuity through the splices looked good. Cranked the car over... still no joy.

So moved on to testing power to the injectors. Good solid 12v to them on hot side. Ground side there was resistance but not complete continuity, dunno if this is normal or not. Went in to grab the wife to crank it over to check that ground was being pulsed properly. She starts to crank and I see the meter start jump and..... the engine starts to fire. So, plug the unplugged injectors back in, and it fires right up. :/

So, I haven't done anything between the last attempt to fire it up and this one, but now it's running. There's has to be a short or pcm problem or something, and I don't like problems going away where I can't point to a "I fixed this" solution. With the car running I gave all the wiring harnesses a good shake, even the wires into the pcm under the dash. Wouldn't die.

Could it be the cold weather and the pcm? Thinking over what was done the only thing new today is that I've left the key in the run position for longer than usual due to testing power to the injectors. I know electronics can get temp sensitive.

BillBoost37 01-05-2010 02:49 PM

The intermittancy is leaning me toward a pcm. 92-93 aren't overly common for issues. However I have seen and experienced some. Like Peter who had a 92 with tons of knock and no other symptoms. Finally out of desperation the pcm was changed. The car ran beautifully.

The ground to the injectors is controlled by the pcm. Not sure what resistance/etc you should find there. It's interesting that when you were messing with the fuxe (nearish the pcm) that the car started.

This is going to sound wacky..I promise it's a certified advanced method of testing though.
Start the car (if it will)
Stomp on the floor next to the drivers door sill.
Stomp on the floor by the passenger footwell and especially up near the firewall (pcm area).
Then stomp on the floor by the passenger door sill.

The door sill tests are checking the ground busses that are located by each. There once was a member whose car wouldn't run until he stomped by the drivers door sill. And he drove home stomping. Cleaned the ground buss and it never happened again.

Stomping by the pcm is desiged to check for cold solder joints etc that might be acting up due to weather etc.

Mike 01-05-2010 02:52 PM

You gonna do an article for our Tech Info area Bill? Before GM comes in and patents your idea!

BillBoost37 01-05-2010 02:56 PM

First I think you and I need to go to that reading course. We've both tried to fudge this one a couple times..lol

Mike 01-05-2010 02:59 PM

I know.

kparrent 01-05-2010 03:05 PM

Quote:

Originally Posted by BillBoost37 (Post 1417207)
There once was a member whose car wouldn't run until he stomped by the drivers door sill. And he drove home stomping. .

LMAO, and I thought having my turn signals out was a hazard.

elmerfud 01-05-2010 03:07 PM

I'd actually left the car running. So I went out and did the stomp test at the areas indicated. Didn't die or sputter. Decided to give the all the wires another shake test still stayed running.

Maybe I'll get another pcm just to say I did something.

Mike 01-05-2010 03:12 PM

Well, if you do. Keep the old one as a backup.


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