Calling Mr. Smooth Idle Dennis Hogan

[TurboSlacker]

Dennis,
Give us your tips on how to get a turbo V6 to idle and run smoothly.

I've tried many things to try and smooth out my rough idle and even a little roughness at rpm's above idle:
Ignition coil pack & module
Plug wires
Spark plugs
PCV valve
Downpipe clear of frame
MAF swap
Ran engine without accessories, i.e. serpentine belt off, still rough
Disconnected CAM sensor connector while engine running to put it in batch mode - still rough
Lifter preload – shimmed both rocker arms
GM top engine cleaner
ECM

Other ideas I had are:
Motor mounts
Head gasket
Head valve not sealing
Piston ring
Torque converter

All my Scanmaster numbers look great and the car runs strong. Vacuum is steady at 16. The engine rocks back and forth more than most turbo V6's that I've checked out.

What else should I troubleshoot or test before ripping the heads off?

 

[Bad as L]

I'm not Dennis but some peaple think I look just like him

Fuel injectors

 

[TurboSlacker]

Even if you look like Dennis, thanks for playing.

Rough with both clean/flowed stock injectors and 37# Delphi's. But I have going to have 50# to try out soon. Not anticipating any improvement.

I really am suspecting headgasket at this point. Would make sense if blown between combustion chamber and intake or btn two adjacent combustion chambers.

More ideas?

 

[JP87GN]

If its head gaskets you better get that sucker apart and running tip top before TTV or you may get whooped on

 

[Bad as L]

When your changing injectors, did you have a close look at the injector wiring harness. They have a habbit of rubbing thru in places.

If you knocked a gasket out between the cylinders you would see that right away with a comp test.
Dale

 

[boostedmaxPSI]

Originally posted by Bad as L
When your changing injectors, did you have a close look at the injector wiring harness. They have a habbit of rubbing thru in places.

If you knocked a gasket out between the cylinders you would see that right away with a comp test.
Dale

I checked the injector harness, everything was routed correctly with no pinched wires.

FS

 

[geno]

Did you check the egr?

 

[boostedmaxPSI]

Dan,

Just drop a Cadillac Northstar in, that'll idle smooth

 

[geno]

Never take the heads off unless you know for sure there leaking or know bad You will NEVER get the heads sealed as well as the factory and history show this to be a fact. The factory had a tool that torqued all the head bolts at the same time witch cant be duplacated That gave them even clamping instead of going back and forth accross the head bolts torqing them.. At least this is what ive read on why the factory installed head gaskets take more detonation before failure.

 

[TurboSlacker]

Josh, I plan on kicking your butt on the track even with my rough running engine

Geno, I totally agree with not removing the heads until everything else is ruled out. I'll hold off until more info points to an internal problem.

EGR is relatively new. But worth swapping to try out again.

I don't have much experience doing compression testing or leakdown, so I could use some help doing this. I tried doing a compression test myself and did obtain 150-160 in all cylinders. Pearcy did a leakdown test four years ago and found #6 leaking 40%. I really need to do an accurate compression and leakdown to understand the health of the internals.
Gene, can we hookup sometime to do this ?

 

[JP87GN]

I was just trying to get you fired up way early. I have all the stuff to perform leakdown and compression tests and we could play with my car as well. Let me know if your interested.

 

[boostedmaxPSI]

Originally posted by JP87GN
I was just trying to get you fired up way early. I have all the stuff to perform leakdown and compression tests and we could play with my car as well. Let me know if your interested.

I'm interested! Never had it done and would like to see how "HEALTHY" my little LC2 still is...

FS

 

[JP87GN]

You guys just tell me where and when, I have to tell my bro to bring the tools home,He's the machanic and I'm just a dumb bodyman.

 

[TurboSlacker]

I'm up for it this weekend, Josh and Frank. How about my place on Saturday or Sunday ?

 

[JP87GN]

Fine by me, I'll tell my bro to bring the stuff home. Is there any other specialty tools you might thing we need? Do you have an air compressor? If so , what fittings you use?

 

[TurboSlacker]

I do have an air compressor. I have extra fittings. I don't remember the type of fittings that I use.

PM me your phone number and well arrange the time.

 

[boostedmaxPSI]

Can I drop my car off? )))

 

[TurboSlacker]

Sure, Frank. And I'll detail your car for you while I'm at it

Seriously, if you want to we'll take care of your car while you're away. Don't pay any attention to the stock turbo that somehow swapped onto your car - geez my GN sure pulls harder now

 

[JP87GN]

Doner car

Yeah, I might had a built trans when you get back!

 

[boostedmaxPSI]

Originally posted by TurboSlacker
Sure, Frank. And I'll detail your car for you while I'm at it

Seriously, if you want to we'll take care of your car while you're away. Don't pay any attention to the stock turbo that somehow swapped onto your car - geez my GN sure pulls harder now

Too Funny!

Someone just stole my GNx style center caps off my car today at work. The sad part is the car is outside my office window!