97 SE ... Intermittant Frustrating Crank No Fire

[Timmeraw]

Hi,

Ok I have been doing a lot or research and I know that this is a common problem with the GM/pontiac family with several different possible fixes but I thought I would try anew.

My son's 97 Bonny SE that I purchased for him to go to work/college last fall has had an intermittent issue(s) that is driving me crazy to try and fix. The issues are that ever increasingly ...mostly after sitting cold overnight or for hours during the day, it will crank over fine but will not fire. The other issue(related I am sure after research) ..is that it will periodically stall out when rolling to a light or turning into a drive and every once in a while(and this is scary) cut out on the highway.
Eventually after several tries...letting it rest for a bit etc. It fires right up and will do so sometimes for days in a row(tho it is getting more frequent for sure).

Here is what I have tried. After research the most common answer is Crank Position Sensor.....which I replaced(kind of a pain behind the H balancer). Actually I have to ask my son if he has any enroute stalling since then...if not maybe that was that prob? Another possibility is the ICM....Got a couple used from a mechanic I know and no diff. MAF sensor....havent replaced but cleaned with a $14 dollar can of cleaner...no diff. Dug out the ground bus under floor trim on drivers side and it was not corroded but put dielectric grease and put back together. Checked that there was fuel pressure on rail(not officially but it is squirting out from valve when not starting so fuel pump is starting). I even tested the coils and they are fine.

Check engine is on(sometimes disappears but comes back. Had codes checked and there were two....#1 cylander issue and Crank Position....this was before I replaced it). Oh and I forgot...earlier I replaced plugs and wires.

Now what?

Any suggestions and ideas are greatly appreciated.

Thanks,
Tim

[bill buttermore]

Could be the ignition switch. You could test this by wiring a small lamp (I use a resistor and an LED these days) to the ignition feed from the switch to the engine, and watching to see if it goes out when the stall condition is present.

[Timmeraw]

Thanks,

Can you detail how to find "the ignition feed to the engine" so I can test it? I was wondering if it was a VATs issue and was going to bypass the key resistance with some resisters below the column but since there is no flashing of security light etc I ruled it out. Something is allowing strong crank and spark but disabling the fuel injectors ....PERIODICALLY.

[Timmeraw]

Actually I think I have it solved....a bit early to tell but if so I am embarrassed to say the least. After some more searching was thinking maybe just maybe the battery was not just right which apparently will cause the ICM and PCM for that matter to just shut down. I was hearing noise on the alternator so I took it to Auto Zone to do the free battery/alternator and code check for that matter. Battery/alt checked out fine. Codes showed Crank position again. Having already replaced I figured I would grab another while there(long drive from me) just in case. When the guy brought it out and I looked at it I knew something was wrong. It did not look like the one I replaced before. He showed me the CAM sensor and I realized I had replaced that before and not the Crank Sensor I had intended to the first time.

So net-net... it went really quick after having done the same process before and seems to be working great right now.

Cam/ Crank Position Sensor...in nearly the same "position" behind the harmonic balancer. Too close all around.

Oh well....good news is that not only are they both reasonably priced ....worse case I have a new Cam sensor that I can rule out from now on.

Jeeeeeezzzzz Live and learn I always say. Every time you do something it gets exponentially easier the next time right? I am really getting the secret of the 'real' mechanics I think?

[Bonnefied_GM]

I'll probably be replacing my cam and crank sensors in the next two weeks.....does the H-balancer HAVE to come off? The less work I have to do, the better.

[00Beast]

HB has to come off for the crank sensor.