95 3.4L DOHC Monte Carlo Crazy Idle Issue

[bszopi]

I've read thru your procedure (wish your pics were bigger).

That should be fixed now.

[tincherb]

I've read thru your procedure (wish your pics were bigger). I'll check the timing...I'm gettting to be a pro pulling off that upper plenum. My only question in regards to walkthrough for this 95 is, will the cam flats on both heads be facing up at TDC. I agree there could be a couple things causing a miss, but its odd to me that the plugs are black on 2,4,6 and pulling the spark plug wire off one at a time on those cylinders doesn't make any noticable difference in engine sound. Would you agree?

[SappySE107]

If you pull the upper, you can compare the cam flats on the rear bank. You can check the front easier. Look at the cam timing walkthrough to see how the flats line up vs the crank pulley timing mark.

You could have an injector that isn't spraying as well as the rest. The cam timing isn't the only thing that can cause this. Your EGR could be stuck open a little as well.

[tincherb]

Thanks for the response. It is 170 plus/minus 5 psi on all cylinders. The measurements were not difference between the two head is what was most suprising to me. Is belt strech common enough that someone else had heard of symptoms that it would cause. I'm gonna have to go a little further I guess.

[SappySE107]

170 on all cylinders? It could be the timing is off (not a jumped tooth, thats 12 degrees each tooth). Belt stretch will account for 1 bank being different than the other.

[tincherb]

OK...Put the Delco wires on and still missing. Its definitly coming from 2,4,6 cylinders. Did compression check and getting 170psi wet. Whats going on here? Could timing be out enough to run bad but still have compression? I need some input here, I'm baffled. The ingition control module...can that thing cause problems like this?

[tincherb]

Timing belt tensioner is probably bad and the belt jumped a couple teeth on that cylinder bank.

So will that happen like that? I questioned a friend if timing would jump on one set of cams but we convinced our self self that if timing jumped, it would do it on the drive cog (ie everything is out), especially as tightly wrapped as the belt appears on the cam cogs. Guess I'm gonna have to check that out. I should be able to do a compression check and see that...right?

[jman093]

Timing belt tensioner is probably bad and the belt jumped a couple teeth on that cylinder bank.

[tincherb]

Working on this car for a friend which had a bad intake gasket leak so the typical idle surge/stall thing was going on. I replaced the gaskets (upper/lower) and put new plugs and wires on. Started up and now have the slightest miss at idle. Its not lumpy just a slight sputter. Here is the odd part. I noticed when I pulled the wires off cylinders 2, 4,6 the engine makes no noticeable change. 1, 3, 5 definitely cause a problem with the engine. I know the spark is getting to the plugs on 2,4,6 as they arc inside the head when pulled off, just don't know if they are in time. I'm certain they are on the correct coil as well. Also 2,4,6 spark plugs are black while the other three are clean. I'm getting ready to put AC Delco plug wires on and see if that has any change (I don't have much confidence in that being the problem). I would like some suggestions before I put the upper plenum back to together to fix this. Thanks.