Mechanics

UPDATE 97 NO START STILL NEED HELP BAD PCM?

1997 Chevrolet Lumina • 220,000 miles

Chevrolet Question
Asked on September 28, 2011

1997 Chevrolet Lumina Engine Problem with 220000 miles

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Car No Start Injectors Not Pulsing
I did manage to start it once the other day using starter fluid & putting a little gas into cylinders my self and once car started it ran better than ever it seemed to have much more power old o2 sensor was bad and ran way to rich. But once I shut it off I could no longer start it. It seems that I dont get an intitial pulse from injectors but once it gets up to certain rpm they work. I have changed fuel pump, filter, ignition module coil packs and crank sensor.I have good fuel pressure good spark on all plugs I checked for power to all injectors and checked the resistance of all injectors about 12 ohms each. But did not get pulse with noid lite. I tried unplugging sensors and starting no luck there & not vats issue tried both keys and security light always goes off. More than 5 gallons fuel in tank. Not been able to restart with starter fluid. When I started it the first time I poured gas into every cylinder kinda hard to get to 1, 3, 5 now that its together and just 246 doesnt spin it up fast enough I thought for sure it had to be ignition module or coils sence it ran well after started so took back new module exchange for another one and no luck. They tested coils they where good.


ok! First you asked about codes and check engine light. It does work and it was not on when I got it started the other day and scanned good But now in my recent attempts to restart and unplugging sensors I had an arm load of codes but they where all from the sensors I un plugged and mifires on 1, 3, 5,

I checked voltage to both sides of fuse for fuel injector one side 12v the other.3 I tried it key on and while cranking no significant change.

I dont know how to check anything at pcm but another question would be does the pcm use a different ground or something for pulse after start I thought that because it ran well after start the pcm was fine I took it through gm recommened drive cycle all sensors came on all ok. Also If it is pcm and I buy one already programmed for vin does that mean I can just put it in and start it or is there some other issue with vats or what if I have a replacement transmission or something will that matter with a new pcm. I am trying to figure out if I could do this or if it would have to go to dealer. Are there pins on pcm that I could ck resistance to verify this?
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Tutter2367
September 29, 2011.



Does this system have 2 crank sensors? The one on the block that goes in between the engine and trans and there may be another one behind the crank pulley.

Roy

ASEMaster6371
Sep 29, 2011.
It has two I changed 7x the other one 24x I was told had nothing to do with start up the one I changed on passenger side rear of engine behind pulley accessed through wheel well. I changed it old one checked out good both around.6 v ac when cranking. 24x I think is under the timing cover.

Tiny
Tutter2367
Sep 29, 2011.
No, it is behind the crank pulley. The crank sensors are responsible for the injector pulse. I am not sure which one controls it the pulsing of the injectors.

Roy

ASEMaster6371
Sep 29, 2011.
What do you mean no! I replaced 7x witch is on the back of the motor that is the one responsible for start 24x on front not important till 400rpm or something like that 7x responsible for start!

Tiny
Tutter2367
Sep 29, 2011.
Do you have the proper signal going to the pcm?

Roy
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ASEMaster6371
Sep 29, 2011.
I checked pulse signal at ignition module dont know how to test at pcm. At fuse box for injector 12v one side nothing on other no pulse when cranking

Tiny
Tutter2367
Sep 29, 2011.
How did you check the pulse from the sensor? Did you us a scope?
The pcm does ground the injectors only after seeing the proper signals.

Roy

ASEMaster6371
Sep 29, 2011.
I used multimeter I was told if it produced between.5-2 volts ac when cranking it was good. Besides I did change sensor anyways I know multimeter not as reliable as scope but the fact that old one new one checked same and I am getting spark on all cylinders I would think that that is not the problem

Tiny
Tutter2367
Sep 29, 2011.

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