Boosted Chemist

Today i did my clutch and after finishing i decided to check out my idle problem. I turned down the idle to where it finally stopped surging with my foot on the brake. Now it sounds like its running on three cyclinders. Next i pull plugs and no responce from #4, even though i have a bright blue spark.

Kill the truck and pull the plug and there is no gap! This happened before in that cyclinder. So regap the plug and run the truck for like 5 minutes. Kill it and the plug is gap less again WTF? im running ngks (i have to get the part number) but they are all the same and this is the second set that ive encontered piston #4 hitting hte plug. Is there supose to be a shorter plug for #4 (you can see about 4 threads are burned up on the plug meaning its too long)

ps. CLutch was cake did it in like 4 hours on a lift with a tranny jack

Boosted Chemist

plug ngk bpr5ey





look at the impact

86toyota

The only thing I can think of is too much carbon buildup on the piston head. Maybe the head has been shaved in the past making the clearance closer also. The first pic I can't see if there's a gap but the second it looks like a small gap.

Maybe double up on the gaskets to get by until you find the real problem.

jimbo74

wow, i run those same plugs in my truck and never had a problem.. my head was also decked when i redid the headgasket

Boosted Chemist

I changed out the headgasket a year ago and its was the original, and i did't shave the head. Idk about the carbon, that would have be carbon turnign into diamonds lol. The only other thing i can think of is that the plug sits with the tip pointed down and maybe the thread is ÅÅÅÅed up, i you get another half turn the plug would face down (tip pointed toward the head instead of piston)

86toyota

No matter which way the plug faces in the cylinder it should NOT hit. You can buy indexing washers to position the electrode in the head ,but that's not your problem. I would think it's hitting the valves also.

Does the engine rap or make noises indicating loose nuts on the connecting rod. That would let the piston travel more.

Someone's had to of been there before to offer some advice.

Boosted Chemist

Im wondering could a loose valve cause this? (how does a valve get that loose? maybe a compression test will tell more?

Boosted Chemist

any other ideas before i start tearing it appart? I wonder if i have a faulty egr and at idle its still feeding exhaust into #4 causeing a misfire/detonation causing the plug to be bent

Boosted Chemist

maybe i should repost under a new title, not enough bites on this bait, lol

phorunninduke

I had a similar problem for a while and I found that the head had been cross threaded and was going in at the wrong angle and that is why it was bending it..
When you gap the plug, install it and take it out without running is it bent?

Boosted Chemist

i should try this, were u able to fix it with a tap?

superjoe83

are there any specks of aluminum on the plug, from the pics it looks like there is, is the engine making any knocking or pinging noises

phorunninduke

Yeah, I used a helicoil kit however. I would make sure the plug gap gets messed up Without the engine running first however. Then possible crank the engine over by hand 180 and check again to make sure it happens again and is not a piston or valve. If for somereason the gap is fine WithOut the engenge running, turn the engine by hand and check often to find out where it is getting bent to narrow down where it is happening. It seems to me if it was a rod/valve deal it would be pretty noisy but you never know.


edit, yeah those threads look a little messed up.

Boosted Chemist

no pinging noise, just a bad idle, under load it runs great.

freedyv200

having the same problems with my 22re, jzt got done wit the hg and now i gotta deal with the spark plug tip gettin bent