Major misfire

[dropinem2low]

The spark plugs look new because they only have about 30 min. on them. Under a magnifying glass I can see that they have a slight discoloration, a light white or yellow color. Will be able to post pics thurs. or fri.

[old_master]

Have you checked the distributor driven gear? If the distributor is not centered in the intake manifold hole, it will wear the teeth on one side of the gear down. Have you checked camshaft retard? Did you do a crankshaft position sensor relearn after you replaced it? (must be done) GM dealer issue shop manual warns not to exceed 75psi when restricting the return line. If you restricted the return line and had a pressure reading of 110psi, it would be a small miracle if the fuel pressure regulator is still good.

[dropinem2low]

The dist. Gear is good, no abnormal wear. Camshaft retard, it's been a while
, if I remember correctly it was advanced about 20 or 30'. Didn't do a comp relearn on the crank sensor. 110 psi was at the pump with no return line restriction.

[old_master]

Camshaft retard must be zero degrees plus or minus 2 degrees. Rotating the distributor is how it's adjusted. The lock ring on the distributor base will allow slight movement to adjust camshaft retard. The only way to check and adjust it is with a capable scan tool dialed in to camshaft retard. The cheapie $400 jobbies that the auto parts stores use for retrieving codes will not access the data.

Any time the crankshaft position sensor is moved in its mount, or replaced, the relearn MUST be performed. Again, only a capable scan tool can command the ECM to perform the relearn. The crankshaft position sensor and the camshaft position sensor, (in the distributor) work together to monitor engine misfire. That's all the camshaft position sensor does, it has nothing to do with ignition, or ignition timing.

[dropinem2low]

Timing is now at "0", and the crank sensor has been taken care of by the local chevy dealer. There is still no change in the miss.
Would a complete ecm reflash have any effect? I replaced the ecm out of a known running truck. I can't think of anything other than replacing the entire wiring harness. Thanks for your help so far.

[rhandwor]

Originally Posted by dropinem2low

Timing is now at "0", and the crank sensor has been taken care of by the local chevy dealer. There is still no change in the miss.
Would a complete ecm reflash have any effect? I replaced the ecm out of a known running truck. I can't think of anything other than replacing the entire wiring harness. Thanks for your help so far.

Did you match the numbers on the ecm?

[dropinem2low]

It matched by year, make, model, and engine. The only difference was it was for an automatic tranny.

[AutoService101]

Originally Posted by danielsatur

Running Rich with white smoke!
Check your coolant level, and look for coolant in oil.
Is the coolant reservoir tank contaminated with oil?
These are symptoms of a bad Inake, or head gaskets

I have to agree. When a vehicle is running to rich it will blow black smoke, not white. The only thing I have ever seen cause white smoke is a leaking head gasket. Just because you rebuilt the engine does not mean you do not have a leaking head gasket. How many engines have you rebuilt?? I know guys that have rebuilt 100's of engines and still jacked something up at one time or another and had to go back and redo their work. Maybe i am wrong but what else will cause white smoke???

[dropinem2low]

I've rebuilt too many to count and more head jobs than I want to remember. Do you think I should Magnaflux the heads? I cant see any cracks but I don't know if there is small cracks or even if that small of a crack would cause that big of an issue. White smoke can be caused by burning coolant or burning oil. Burning coolant can come from a cracked intake or intake gasket leaking into the cyl via open valves or a buster head gasket. Same thing goes for burning oil, exept it can also come from bad rings. Now, the question is, What would make an engine go from running like a top to missing on all six cyl from one start to the next?

[rhandwor]

Napa sells a test kit for combustion gas in the anti freeze cheaper than pulling the head.