I had a hard time with the "tech" or "talk" question, but for lack of a "SWAG" forum, I decided it's more tech. <img src="/forums/images/graemlins/smile.gif" alt="" />
It's passed midnight and I'm up researching my pinging problem, and the proverbial lightbulb just went on. Here it goes:
My spark plugs were all fouled-up with carbon, indicating a rich mixture or weak ignition. My coil checks out fine...I don't know about the rich mixture, but I have a new O2 sensor, no codes, and have been going through fuel injector cleaner like mad. So I'm figuring that the pinging is due to carbon deposits in the CC, but *if* I'm not running rich, and my ignition is okay, then why the carbon? So it just occured to me...that little braided grounding wire on the back of the head. It wasn't there when I replaced the head (some yokel must've lost it when replacing the HG prior to me), so I didn't know about it until a couple months ago. I saw one on a junkyard Trooper and thought it might be something I should have, but had no idea why, so I snagged it and installed it. Can you even believe I fussed with that bolt on the back of the head for about an hour, without a clue as to why that ground needed to be there? Anyways, my idea is that the time spent without that ground explains the weak ignition, causing carbon build-up, causing pinging. Does this make sense?
<img src="/forums/images/graemlins/cheers.gif" alt="" />
Phil

I can accept that. A bad engine ground can cause many problems. You figre that most of the points the engine and tranny connect to the frame they are connected with rubber bushings, with no grounding effectivly. There is only minsor small grounding through other sensors. The main way a plug works is jumping a spark fromt he electrod to ground. If the engine is poorly grounded it can't jumpo the spark as easily. Hence the reason why most vehicles have an engine ground.

Does this sound logical? Little grounding strap is the root of all evil?

Why, absolutely yes <img src="/forums/images/graemlins/lol.gif" alt="" />


It's always a ground.........da ground <img src="/forums/images/graemlins/shiner.gif" alt="" />


"Hey, my truck doesn't work, what's wrong with it?"

"Did you check your grounds foo?" <img src="/forums/images/graemlins/mrt.gif" alt="" />


Cheers,

Yep, bad grounds are the cause of many, many electrical problems, and certainly could be the cause of yours...not the only possible cause but a definite candidate.

Where's Rubo when you need him? <img src="/forums/images/graemlins/smile.gif" alt="" />

I could see that chain of events happening, since the cylinder head cover can be pretty well isolated, sitting on its rubber gaskets, connected to ground by vacuum lines. <img src="/forums/images/graemlins/pfft.gif" alt="" />

That said, internet diagnosis can be difficult... especially when it comes to root cause. We can talk about specific symptoms, tho -- if you think you have carbon-coated your combustion chambers (pinging early, down on power, carbon on the plugs, etc.), try feeding your motor some water. A little at a time is the key -- too much and you'll hydrolock, which is BAD -- so be careful.

Generally, what I do is take a jar of water and disconnect a small vacuum hose and let the running motor suck off the surface of the water (don't just drop the hose in the water). Use one hand to turn the linkage at the throttle body to get off-idle, and listen to the note of the engine. It will struggle a bit as you suck in water -- when you hear that, lift the hose (stop sucking water) and let it smooth out. Lather, rinse, and repeat... Lather, rinse, and repeat. Run a quart of water through the combustion chambers over the space of 15 minutes, and you'll effectively steam-clean the head and piston tops. Those of you who have blown a head gasket (literally) have seen the effects, where the piston with coolant leaked into it is clean and shiny, when compared to the other pistons that have normal combustion deposits in them.

If done carefully, this won't hurt your engine, and might help.... but it should eliminate the possibility of carbon-coated combustion chambers, and the resulting rise in compression ratio with pre-ignition.

Randii

Hmmm, I may have to try that on my Tahoe, it is pinging some on part throttle acceleration.

Thanks for the replies, gents. <img src="/forums/images/graemlins/cheers.gif" alt="" />
Now I feel like a genius and a complete doofus all at the same time. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />


That's exactly what I was thinking. <img src="/forums/images/graemlins/smile.gif" alt="" />


When I got my head off, I initially thought, "Wow, I have one brand new piston!" Then I thought about it for half a second... <img src="/forums/images/graemlins/ignore.gif" alt="" />
Well, hopefully now I'll have four "brand new" pistons. <img src="/forums/images/graemlins/smile.gif" alt="" />

BigSwede: here's a link about detonation and preignition. http://www.misterfixit.com/deton.htm

I sure hope this works. I was about to give up and take it to a mechanic, but I seriously don't want to do that. It's not that I'm too proud...I just have trust issues.
Now I'm tempted to take some 4 AWG copper wire and run another ground, just for S&G's.

<img src="/forums/images/graemlins/cheers.gif" alt="" />
Phil

PHIL WHEN YOU REPLACED YOUR CYL HEAD DID YOU HAPPEN TO NOTICE THE COMBUSTION CHAMBER FOR THE NEW ONE, DID IT LOOK EXACTLY LIKE THE OLD ONE , OR BY CHANCE DID IT HAVE KIDNEY BEAN SHAPE OR A TWIST TO THE COMBUSTION CHAMBER, IF YOU HAVE A 93 OR LATER CYCL HEAD, YOU WILL HAVE PINGING UNLESS YOU SET THE TIMING AT AROUND 6 DEGREES , THAT HEAD ON THE OLD SYLE BLOCK WILL RAISE YOUR COMP TO ABOUT 9.0 OR BETTER, AND YOU WILL HAVE TO KEEP THE TIMING BACKED OFF A BIT ,, 93-94 AND LATER 2.6,S USED A MUCH DEEPER RECESS ON THE PISTON TOP THAN THE EarlIer VERSION, IT MAKES A GOOD BIT MORE PWR BUT IT DOES HAVE A TENDENCY TO PING WITH OUT PLAYING WITH IT A BIT , I HAVE NEVER SEEN ANY OF THESE ENG WITH ENOUGH CARBON BUILD UP TO PING , BUT YOU MIGHT GIVE RANDIS SUGGESTION A TRY , IT WON,T HURT ANYTHING , DO LIKE HE SAYS AND DON,T GIVE IT TO MUCH TOO DRINK AT ONCE

FWIW, the lack of a grounding strap can also cause the engine or transmission computer to "work outside it's parameters" i.e. go banannas.

A long handled 10mm wrench is really nice for that bolt. A wrench with a wratcheting head works even better. Either that or have access to a 7 year old with tiny hands. (the wrench is cheaper).

Good Luck,

Jerry,
Yeah, the new head looks just like the old one did. Good thinking on that one. <img src="/forums/images/graemlins/cheers.gif" alt="" />
I did randii's steam cleaning trick and that has helped quite a bit. I can still get it to ping by winding it up in 4th gear, 5th too, but nowhere near as bad as before. Now, I can actually set the cruise control at 65 and it won't ping with every tiny uphill grade.
Maybe I just need to do it a couple more times. The spark plugs were really disgusting, you could almost use them to barbecue, they had so much carbon on them. <img src="/forums/images/graemlins/smile.gif" alt="" />