OK,

So you are saying that a ReLearn process must be done?

What tools are required for this? Is the GM Tech II the only option?


Jan

 

If the timing cover or sensor are out of spec giving a different clearance between the reluctor and the sensor with out any shorts present there will be no code and no signal. This can be easily tested by taking a known good sensor out of a car that runs until its out of range. Then try and start it. No codes and no running car. Chased that rabbit before. The cheaper auto store sensors don't last as long, don't seem to be as sensitive and have been found by myself to be out of tolerance. I've replaced or swapped out sensors from another car in the driveway which I knew had factory original and it worked. If you have confirmed you are getting signal at the blue pcm connection as a did in the link I gave you your problem is elsewhere. Cheap sensors also have more problems with heat. I've had them not run over 3000 rpm when hot and I've also been stuck on the side of the road for it too cool down again at which point it starts right up and runs great until hot then dies like I shut the key off. The trouble shooting procedure doesn't cover these problems and the pcm won't throw a code. On vortec 96-2002 that I have experienced. The car has to be running GOOD to do the relearn procedure. The cars I worked on a phantom miss may appear without doing the relearn causing torque convertor lock up issues but they were all timed good enough to run good and not miss. Only the pcm can see a correlation issue and interperet that as a miss even though one doesn't exist. Once you get it running good take it a shop that has a tech 2 and have them do the crankshaft relearn. I've had mechanics take a 5 in the parking lot works best. Captain Hook has a lot of good information but I have experienced different in this case, no disrespect to him.

 

I have got a code before but that took some abuse to the engine and time before I ever got a code to appear. When I replaced it with one from Autozone (cheap one) it didn't last a year and didn't get codes when it failed. I also had to modify the sensor flange to get it close enough to read. After that, ac delco or better for me.

 

The new sensor is a AC Delco one so there we are good.

When I looked for parts I saw that you could by some shims for the sensor, I now understand what they are for.

Maybe that is an option to try to make it fit to a better focus so the ECM think it is correct.

I might find some one over here that has the Tech II, but they are about 100 miles from me and that would mean taking it on a trailer. I'm out in the woods you see :-)

Thanks

Jan

 

Have you verified you signal is getting to the VCM? If it is, do you have spark? Do you have good fuel pressure? Do you have any codes? Why are you thinking CKP sensor?

 

I have checked the connections and from the Crank Sensor to the ECM Blue connector there is connection. I suspected that one cable might be broken.

Well I'm now lost here.

From the beginning it just died suddenly, I did a spark check and changed the Ignition module, the coil and last the Crank Sensor. After the new Crank Sensor it started immediately without any hesitation. So I thought everything was good. After a few short trips it died again on the road.

It did then start for a short time and died again, now it won't start at all.

So what can be left. I hear the fuelpump going when ignition is turned on. I have some pressure in the fuel lines but I haven't measured it.

But if the fuel pressure is low I would still get spark?

Could it be the Pass-lock?

I'm stumbling in blindness at the moment...


Thanks


Jan

 

Yes with low fuel pressure you still get spark but no fuel will come out of the injectors. I've just experienced fluctuating fuel pressure causing me problems. The fixes you performed could be coincidence. Maybe lower temps contributed. Do you have good pulsing strong spark out of the coil wire? If yes definitely check fuel pressure.

 

Here's a link to my intermittent fuel problems here on this site. https://blazerforum.com/forum/2nd-generation-s-series-1995-2005-tech-41/intermittent-low-fuel-pressure-85337/

 

I have got myself a fuel pressure instrument and tested my dead car with it.

Fuelpressure is OK at 55 psi and it is holding it during cranking. But it will not fire...


Jan

 

Your reading of 55psi will cause hard or no starts, stalling, and poor overall engine performance if you can get it running. All fuel delivery tests are made with the engine off. When the ignition is initially turned to the run position, (don't crank the starter) the fuel pump activates for ~2 seconds and shuts off. Fuel pressure must be tested during the 2 seconds when the pump is activated. Pressure must be 60psi to 66psi. It must remain above 55psi for at least 10 minutes after the pump shuts off. The next step in diagnosis is to check pressure and leakdown at the fuel filter outlet. The tester must be modified so it connects directly to the fuel filter outlet. All pressure and fuel flow must end at the tester. When the pump is activated, pressure must be 73psi to 108psi and it must remain above 55psi for at least 10 minutes after the pump shuts off. Post your results: they will tell if the problem is in the tank, or in the plenum.