I had exactly the same thing after 100K service. Eventuated that it was PTU. All the tests in the service manual for the PTU check out, all continuity, etc, etc all looked fine. I got a brass toothbrush and contact cleaner and really went to town on the contacts and she fired up after that. Had a Code 55 as well and a weak spark, but not strong enough. I guess the point is, all the PTU tests and wiring to ecu and coils said everything was ok, and visually i had spark and fuel, but there just wasn't enough spark. Something K-zed mentioned
anybody know or had the valves not closing all the way ??? when i have my hand over the lower plenum it sucks my palm in the intake but then pushes my hand back off is that normal?
No, not completely normal. You will get some reversion, but not heaps. Only things that I can think of that will hold valves open are: Lifters pumped up/seized Foreign matter between cam and lifter Foreign matter between lifter and valve (really not likely at all) Foreign matter between valve and seat Bent valves Have you got clearance between the cam and the lifter when the valves are open when they should be shut? Use a feeler gauge to check.
how long did it take you to do the plenum pull ? maibe the car was left unused for a while cousing the lifters to seize up , did you do regular oil changes ?
no clearance between cam and lifter the come right up against the cam just done oil change and filter now just to release all pressure and take any bad oil out of system.
compression test 175 on 3 and 170 on 6 the rest 0 compression seems lifters are stuck and not closing valves on cylinders 1,2,4,5
Lifters wont be stuck open. My guess is gasket material or rags under valve seats. Turn the engine over off of the crank, when each intake valve opens all the way, shinea good light in there nd have a look for something jammed into the seats, you can pretty much see the whole valve seat. Get aq rteally good vacuum cleaner and suck the crap out.
Got me stumped. Something must have happened during the plenum pull > push period to contaminate the valves and or lifters... a rag or other debris perhaps? Did you keep lower plenum sealed during plenum off?
yeah kept lower plenum sealed have cranked it with cam covers off a small crank at a time and no rag or foreign material in there ? only took cam cover off put new gasket on and back on again 10mins max
Another option is to use a leak down tester if you have one, if not use an air blower, with the intake valves open, blow air into the spark plug hole. My worry is that what ever has gone into the port may have bent the valves. I have never seen lifters jam fully pumped up with the engine being switched off. Even on engines that have sat for a long time, the lifters just drain out, very rarely do they sieze. I doubt the issue is lifter or cam related, unless it has slipped the belt and bent the valves, again unlikely but can happen if an idler or tensioner has failed. If you are certain that there is nothing under the valve seats now(there may have been when you first tried to start it), check the cam timing, then remove the cams and see if the valves seal, if they don't pull the heads. There is really no other option here other than what I have listed above.
taken timing covers off inspected belt and is still on correct timing points when blowing the compressed air into the spark plug holes what am i looking for or to hear ?
With the valves closed you shouldn't be able to hear air rushing out of the intake, with them open you might just blow some crap out of there and get them to seal again. If they won't seal you will need to remove the heads and valves to see what has happened.
tried compressor with valves closed i can still hear the air going past them looks like its time for heads to come off
You could try a bore scope as interim alternative to heads-off. I find this really curious that all was fine pre-plenum pull, but now numerous cylinders are faulty. Lets say worst case scenario, a bit of debris has fallen into a cylinder, but how does this happen to four cylinders???????
