Need input on this issue

[machinegun]

OK, I think I already know the answer but thought since I am tired, frustrated and just plain aggravated I would just ask for suggestions

I have 109 stkc bloxk, crank rods with diamond 30 over pistons. Stock ported heads from Webber and intake from webber and comp cams 212/212 roller cam with custome pushrods and stock rockers. Assembled with all stud ARP hardware and cometic head gaskets. 42 pound injectors alchy and the usual compliment of hardware with about 1500 miles on it

The other day while driveing the car was under 10 psi of boost and the car popped and died. I had an issue with the plugs earlier so doned a new set and leaned out the tune some and all was going well until the pop. Once I started the car it seemed to run very poorly.

It is down at least 1 cylinder. You tell from the way it runs and has no power under boost. You can feel it missing.

I tried new plugs and wires and coil pack. No change. I have checked the oil and rad and can not find oil or water in either one. A compression test shows 155 psi across all 6 cylinders. I can so far find no leak on the outside of the block and when running I do not see any smoke or steam coming from the valve covers with the breather pulled. I can not hear any weird noises from the cam and the thrust checks out fine.

When running the BLMs are 108 to 119 O2 in the 765 range and coolant is steady at 162 degrees.

So anybody got any ideas? I am open to any input.

 

[Amelio]

hmmmm sounds like a good one, if you think for sure you have a dead hole I would first try to figure out which one. That will start to help point you in the right direction of what to chase.

Second you say there was a loud pop under boost and then the car ran poor. I had this same thing happen to me and the fix was very easy. Double and triple check your hoses from your intercooler to your turbo these guys can slip off or at leat loose seal under boost when that happens you will get a POP and think something blew up. Once that has happened the car will now be pulling in extra air that the MAF does not read cause a rough idle. Sometimes it is obvious and sometimes the boots move only a little makking it hard to catch when you scan the engine.

Since you do not have oil/water contamination I would not sweat a head gasket. Check the simple stuff. If the hoses look good and secure go back to trying to find which cylinder is dead.

Let us know what you find.

 

[Rodney87GN]

Double and triple check your hoses from your intercooler to your turbo these guys can slip off or at leat loose seal under boost when that happens you will get a POP and think something blew up. Once that has happened the car will now be pulling in extra air that the MAF does not read cause a rough idle. Sometimes it is obvious and sometimes the boots move only a little makking it hard to catch when you scan the engine.

+1...I had an intercooler inlet pipe slip off just enough to where it would run fine just cruising. But trying to get into boost it had no power and would feel like a misfire and start popping.

 

[KILL4PEACEUSMC]

+3 inner cooler pipe, mine popped on the big end, I thought I scattered the motor for sure! Could hardly make it to the time slip booth. Was delighted to see it blown off at the T.B.

 

[machinegun]

That is a good recommendation, I will go back and check all the hoses.

I am going to try and find which hole is dead by using the old ground out the plug wire trick to see which changes and which does not.

I can gaurantee it sounds, feels and even idles like 1 cylinder just is not firing properly. I fire it up for a few seconds and then felt each exhaust pipe but they seem to feel ok.

I was thinking about pulling the valve covers just to make sure no bent push rods or something dumb like that.

You watch it will be somrthing dumb

I swapped a CP but thinking I may do a CP Moduloe combo swap just to make sure it did nto take a dive on me.

Keep the suggestions coming

 

[bison]

Before starting your engine wet down the manifold tubes. After starting look for one that doesnt dry off quickly.

 

[BetMinesFaster]

If you dont fine an inercooler pipe off you could also idle the engine, and 1 by 1 unplug and plug in the injectors, if you have a dead hole you will find 1 with no change in idle quility or sound when you unplug it, its easy to do If you fine one that makes no difference get a tool to test KV from the auto store and verify that the spark is hot, if its good you can swap the injectors from another cylinder and see if your misfire follows the injector from the dead hole. ifso you have a bad injector, if not id say valve issue or something base engine related. HTH

 

[ryan george]

No wonder I haven't heard from you...I'm probably very little help, but if you need an extra hand, let me know.

 

[jhanson1750]

bison Before starting your engine wet down the manifold tubes. After starting look for one that doesnt dry off quickly.

I use a squirt bottle with water. Start the car and let it idle for about 30 seconds and squirt each exhaust tube right at the head with water. the dead hole will not shed or boil the water. Works great. Jon Hanson

 

[WSLN 6]

WD-40 around the intake manifold while it is idling. I thought I had a bad cylinder too, turned out to be an intake leak....

 

[KILL4PEACEUSMC]

well with 155lbs compression, you can rule out bent push rods and other mechanical issues, my guess is spark, fuel, or inner cooler pipe issue

 

[conn84gn]

If it's not the hose
This happen to me
I had a Push pin let go on my old setup
The little plastic pin that holds the rocker to the shaft.
Rocker walked off the valve stem
No damage 5 cent fix:smile:

 

[turbonut85]

WD-40 around the intake manifold while it is idling. I thought I had a bad cylinder too, turned out to be an intake leak....

Had this happen too. Do all the plugs look normal?? i.e.: are they all a nice tan color? Or, are any of them wet or oily? If the intake gasket goes it will suck air and oil from the lifter galley producing a wet plug and make it run like it has a bad vacuum leak. And your compression would not be affected cause the valve will still be closing.

 

[machinegun]

Well since we have looked at this I found the issue. I replaced the entire coil pack and module from one car to this car. Car fired right up and idles smooth. Put the old one back on and dead hole. After testing we found a bad ignition module. The coil pack was good but module was bad.

I wanted to let you all know. Sometimes you try to help and never get an answer as to what it was so wanted to let you all know.

 

[bison]

Well since we have looked at this I found the issue. I replaced the entire coil pack and module from one car to this car. Car fired right up and idles smooth. Put the old one back on and dead hole. After testing we found a bad ignition module. The coil pack was good but module was bad.

I wanted to let you all know. Sometimes you try to help and never get an answer as to what it was so wanted to let you all know.

You had 2 dead holes if it was the module. The water test would have pinpointed this. Companion cylinders would not be firing

 

[KILL4PEACEUSMC]

Thanks for letting us know and +2 on the 2 dead cyls. the buddy system! gald things worked out