Weird Issue - Part 2

[boatbuster]

Fixed the problem with the van just stalling when it felt like it as described in my other thread "weird issue". Went to use the van this morning in lovely winter weather of snow and wind. The van started right up, drove just fine for about a mile and stalled. Got her started with a lot of tries, but this time it sounded like it was running on 4 instead of 6 cylinders. Tried to get her home but stalled a block from the house and had to get her towed home. Now I can start her, she runs very rough for a few seconds and dies. Even if I try to pump the gas pedal.

2002 Astro AWD

New AC Delco plugs 41-993
New AC Delco wires
New fuel filter (carquest)
New coil
New ignition module
Distributor cap and rotor 1 month old and 3000 miles
Fuel pressure key on / engine off 60 psi with no drop
Fuel pressure engine running (sort of) 55 psi to 58 psi
No codes found
No black smoke out of tailpipe - so no richness issue

I loosened the distributor and tried to move my timing a bit to see if any change - and no difference so I retightened everything. However, prior to doing this I had a P1345, cam/crank sensor correlation, now it's gone.

I was told I might have an EGR issue - wouldn't that pop a code???
Plenty of spark at the distributor. Should I remove the plenum to have a look? If I do remove the plenum, do I need a gasket. How hard is it to remove? And replace??? I don't know where else to look.

Thanks for any help, I am about to buy a beater upper to finish the winter to get to work if I can't find the problem. Where I live, I could not find a descent mechanic to help me, they all want to change parts - that gets expensive.

[old_master]

Check fuel pressure and leakdown again. 60 to 66psi key on, engine off, pump running. Must remain above 55psi for 3 to 5 minutes after the pump shuts off. If pressure stays above 55psi, there are no leaks and no need to remove the plenum.

EGR would for sure set a code.

What brand cap and rotor did you use?

[boatbuster]

Aftermarket cap and rotor - I know -> I should have used AC Delco - cap and rotor are by a company called Niehoff (made in USA). Should I replace those also?

coil and ignition module are from GM - did not want to take a chance.

I noticed a bit of moisture inside the cap, I cleaned it and had no change in situation. I will get a new cap and rotor today (AC Delco) and try again. I will let you know. I will also do a leak down fuel pressure test and let you know.

Thanks!

[57Vette]

I had a similar problem, I can't stress enough to check the spark you have at plugs. Ground a plug where you can get a good look at it, it must be a blue spark, not yellow. If the spark is yellow you have a weak coil, which will make it hard to start and miss like it has lost half the cylinders. I beleive you said that you replaced the coil but you can get defective parts, beleive me.

[boatbuster]

I just got a new AC Delco cap and rotor, I will install them tomorrow.

Tried the leak down test and all is fine. Pressure dropped to 55 and stayed there for 5 minutes.

Is it possible that the timing chain could have jumped a tooth???

I will try all my basics again in the morning if the cap and rotor don't fix the issue. I'm about to have a van for sale real cheap if I can't find the problem.

[boatbuster]

Installed new cap and rotor today. Same symptom. Checked spark with a spark tester and there is good spark. I even replaced the coil again with same results, so I put the old/new coil back and returned the coil I tested with today. I asked the GM dealer if he had any suggestions and he told me that the Cat converter could be blocked - I have lots of pressure coming out of the tailpipe so I don't think that would be the problem.

One of my neighbors said to check the module inside the distributor, but the ignition module is attached to the coil bracket and the only module inside the distributor is the cam sensor. Am I missing something in the distributor? Should I look at replacing the distributor? Plus I already replaced the ignition module.

Since I have had that P1345 cam / crank sensor correlation without any starting or running issues in the past even with that code, should I look deeper in that direction. I already replaced the cam sensor last fall, should I replace the crank sensor or should I have another code? Is there any way to test the crank sensor???

[old_master]

Leakdown is fine, what's the fuel pressure with the key on, engine off, pump running?

The crankshaft position sensor tells the ECM when #1 cylinder is at TDC of the compression stroke. The ECM tells the ignition module when to fire the ignition coil. After 120 degrees of crankshaft rotation, the ECM tells the ignition module to fire again, the ignition coil fires the next cylinder in the firing order, and so on. If the crankshaft sensor signal is interupted, intermittent, or non existant, a DTC will be set and the SES light will come on. If the crankshaft position sensor is faulty, the engine will not run, (no spark, no injector pulse).

The camshaft position sensor tells the ECM where #1 cylinder on the camshaft is in its rotation. The ECM compares the data with the crankshaft position sensor data and determines if the timing chain is stretched, the timing gears are worn, if there are any inconsistencies or misalignment issues with the distributor cap and rotor, just to name a few. The ECM then calculates when to fire the ignition module, which then fires the ignition coil. If the camshaft position sensor is faulty, the engine will still run, and the SES light will come on.

[boatbuster]

Fuel pressure key on / engine off is 60 psi.

This morning after playing with everything I could find - I am now getting a P0102 code - MAF or VAF A circuit low input????? Could this be because the battery was run low trying to start or?????

Should I think about a new distributor???

[old_master]

P0102 means the VCM detected the MAF sensor indicated a low frequency, lower than it should be based on other inputs the VCM watches, which could mean a problem with the wiring, the MAF sensor itself, or a vacuum leak.

[diggin]

Just wondering if you have yet checked the spark plugs , I remember you saying the bosch wires were shooting sparks everywhere and before that it was a p code . Check the plugs and the gap for your model , it is absolutely critical they are correct and/or replaced. I think this is the problem.

[boatbuster]

We found the problem. MAF connector was broken by someone who serviced the van in the past, the contacts were green from corrosion. I cleaned them and reconnected with good readings. The distributor gear was stripped and was slipping, so I replaced the distributor gear. Distributor looked good with no play found in shaft. The cat converter was also limiting flow, I took out one of the O2 sensors and she started right up. So replaced the cat converter.
Works just like it should now. Thanks for all the help!