Question : 95 3.4L DOHC Monte Carlo Crazy Idle Issue

[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.

[jman093]

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

[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?

[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?

[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]

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]

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]

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?

[bszopi]

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

That should be fixed now.

[tincherb]

That should be fixed now.

Unfortunately for me its not.

It appears that the exhaust cam is out. In no way do the flats line up. I made a hold down tool and am going to attempt reset this. Just to be sure...should both the flats on the cams be parallel to the top of the head @ TDC?

[SappySE107]

one bank should have both flats up while the other bank is 180 degrees out. You have to rotate the crank 360 degrees to do the other bank. The flats should be parallel when the timing mark is lined up on the crank pulley. Are the pics clickable? I thought I had them setup originally to be a thumbnail and click to enlarge deal.

If they are black and make no difference in or out, I would say you have a major problem with something. Can't be the coil packs or module because that effects both sides of the motor. Odd to have 3 bad injectors.

[tincherb]

I can't click the pictures.

Anyway, I just got the cam sprockets loose... after taking some time to make a holding tool. I need to adjust one came and it appears the others are ok. I would guess the exhaust cam on the front head is out by 10 degrees. I don't know if this is my problem, but compounded with a worn belt, it just might be. The rear head appears to be in parrallel with the head. I'm trying to figure out the best way to adjust the cam. Looks like i"m going to be here a while.

[bszopi]

I can't click the pictures.

What browser are you using? Also, try pressing CTRL-F5 to clear your cache. The images should be load a larger version upon clicking. Works for me on IE7 (that's all I'm able to test right now).

[tincherb]

What browser are you using? Also, try pressing CTRL-F5 to clear your cache. The images should be load a larger version upon clicking. Works for me on IE7 (that's all I'm able to test right now).

I run firefox so that on Windows 7. That may be the problem. I'll give your suggestion a try.

Just wanted to let you guys know, I learned how and why your instructions were written the way they are. I couldn't get the cam gear off the cam (that will be a question at the end) so I put the hold down tool on the front cams and removed the belt. Just about quitt'n time, the rear cams sprung on me and scared the crap out of me in the process. We'll, when I get some parts, I'll have to get everything back in time.

Now to the question...do the cam gears come completely off the shaft, or are the hold down tools suppose to be strong enough to keep the gears from turning on when the belt is rotated to rotate the rear cams for the installing the hold tool. This is my first DOHC timing belt and I'm accomplishing some rookie mistakes in the process. Oh well, I'll know better next time.

[SappySE107]

You have to pull the lock rings out and then the gears come off the cams. The hold down will keep the cam from spinning while you rotate the drive sprocket/belt as long as the lock ring has been removed.