turbo 6liter woes :\

[6literEat'r]

This isnt going to solve your problem, but do you have any way to scan your car while you are driving? Scan gauges or something? Might help you save the motor if you can let off right when you see knock. I would pretty much never drive a performance boosted application without some type of scan tool.... You would be amazed at the strange shit that can happen when boost is involved.

at the rate that this keeps happening, im gonna start
investing into some more gauges and what not..

 

[Eagle]

ive got 80# injectors...and im running dual walboro 255's

What's your feed line size? How do you have it configured? Parallel rails w/return? What regulator? Base fp? Do you see KR during pulls? What timing are you seeing during pulls?

Detonation sounds like your prob...

 

[boogeyman]

ive fought similar isssues with my supercoupe at anythign over 20 psi it would close up the #2 plug found out i had a bad injector replaced that then after closing the plug 2 more times i got it on the dyno and found out i had a hell of a detonation issue on the front 2 cylinders ( rear fed intake and rear mounted knock sensor) my end solution wasa 1 step colder plug and moving the knock sensor.. i know that i have a diffrent engine but i had a very similar issue as you did

 

[School Boy]

#7 is the hottest cylinder especially with stock rails. I would have a little timing taken out. What is your compression?

 

[Turbocharged400sbc]

You schould get rid of that turbo 3800 and upgrade to the much more reliable and cheaper LSx.......oh...wait







:trollface:

 

[6literEat'r]

What's your feed line size? How do you have it configured? Parallel rails w/return? What regulator? Base fp? Do you see KR during pulls? What timing are you seeing during pulls?

Detonation sounds like your prob...

im using stock line right now, and a stock fuel rail setup..nothing fancy, as I was told this will be sufficient for my power level..base f.p is 58psi, and itll hold while under boost...was also told that when it was tuned...I haven't been scanning it when the problem happens, timing is at 14degrees..

#7 is the hottest cylinder especially with stock rails. I would have a little timing taken out. What is your compression?

compression ratio is stock lq4..9.5:1

 

[Reid@SP]

been having a problem I have been fighting for a sometime now, my 99 trans am, iron lq4, turbo...will occasionally close the sparkplug gap on cyl 7, and it happened once on cyl 2. im running ngkbr7-ef plugs

ONCE it chipped a ring land right of cyl 7, and it smoked out the valvecover breather and you can tell the engine was hurt, as it would also misfire at idle only. so I removed/replaced cyl 7 piston and rings and all was good.. well this happened again today, I got on it hard, rowing through gears, full boost, brand new plugs and wires, and cyl 7 closes the gap again and I had to dogleg it home. im gonna run a borescope down the sparkplug hole and check out the piston, but I am doubting its hurt, as I have no driveability issues after I replace the plug.

car was tuned properly by Brandon, just trying to get an idea of what could be going wrong here, possibly a weak coilpack? or a bad map sensor (3bar sd tune) and its detonating closing the plug gap? HELP!

If I cant resolve this issue, im unfortunately gonna havta withdraw from the half mile event.

The problem is not that the spark plug gap is closed, but what closed the gap in the first place. Replacing the plug will only fix it until the real problem closes the gap again. You most likely have something mechanically wrong.

 

[Zack]

The problem is not that the spark plug gap is closed, but what closed the gap in the first place. Replacing the plug will only fix it until the real problem closes the gap again. You most likely have something mechanically wrong.

Detonation will close the gap on a plug.
Why are you scaring the guy?

 

[willizm]

In terms of fuel starvation I've read many times regarding the #7 and #8 issues where guys that had the fuel line enter the rear of the rails were still having the issue while cylinder 1 and 2(the further cylinders) were fine. I'd have to find the thread but there was a huge discussion on the issue and seemed like venting was one of the things to keep the motor alive as was octane, but wasnt' the end all as is apparent in this issue as he has the rears vented.

 

[Turbocharged400sbc]

I've had chunks of egr carbon close plug gaps but I'm guessing he doesn't have egr
Wouldnt be the first time ive seen a motor get colder/cutback groundstrap plugs in hot cylinders

Hes right though very likely lost a ringland. Seen tons of motors lose lands on the intake side of the piston where it experiences drastic temp cycling

 

[6literEat'r]

I've had chunks of egr carbon close plug gaps but I'm guessing he doesn't have egr
Wouldnt be the first time ive seen a motor get colder/cutback groundstrap plugs in hot cylinders

Hes right though very likely lost a ringland. Seen tons of motors lose lands on the intake side of the piston where it experiences drastic temp cycling

I will find out tonight when I stick a bore scope into the cylinder..

negative on the egr..GONE...

 

[6literEat'r]

Detonation will close the gap on a plug.
Why are you scaring the guy?

I have also read a lot on detonation closing gaps as well, and its happened to me a few times, and thank god the piston lived...and only one time it didn't.

 

[Turbocharged400sbc]

Detonation will close the gap on a plug.
Why are you scaring the guy?

if a detonation/preignition pressure spike in the cylinder caused less than .05% of the surface area in the cylinder to deform and close up im sure the ground strap was nearly white hot and would show evidence of reaching that temp from discoloration

i doubt that by itself the pressure front didnt close the gap

 

[Eagle]

im using stock line right now, and a stock fuel rail setup..nothing fancy, as I was told this will be sufficient for my power level..base f.p is 58psi, and itll hold while under boost...was also told that when it was tuned...I haven't been scanning it when the problem happens, timing is at 14degrees..

What was your IDC @? I can tell u that I run the same injectors and pumps as you, but I have upgraded rails, lines, and fpr.

You need to get a scanner on this car before you continue ripping on it anymore... IF the borescope shows no damage and replacing the plug "fixes" things.

My guess is you're running too much timing, seeing KR, not getting enough fuel... or any combination of the above.

 

[ktraver97ss]

Hmmm tune related..

 

[willizm]

Yeah I second what eagle is saying. Also check IAT to see if it's screaming up for whatever reason. I ran a small filter on my compressor and caused soaring IAT's. Monitor for KR, IDC, timing(although it should be at 14 during your pull), AFR. You got HPT and if you need an extra hand to grab some logs let me know since I live in your neck of the woods. In Vegas this week though home the following two.

 

[willizm]

Hmmm tune related..

Unfortunatly, It probably is as was my isssues.hyea:

 

[6literEat'r]

Yeah I second what eagle is saying. Also check IAT to see if it's screaming up for whatever reason. I ran a small filter on my compressor and caused soaring IAT's. Monitor for KR, IDC, timing(although it should be at 14 during your pull), AFR. You got HPT and if you need an extra hand to grab some logs let me know since I live in your neck of the woods. In Vegas this week though home the following two.

will, ill take you up on your offer...whenever your free if you don't mind helpin
me scan, im still trying to figure out hp tuners...

 

[6literEat'r]

no comment.....I am completely fucking disgusted..

 

[Eagle]

Damn. That sux. Sorry to see the carnage man. :wtc:

 

[Eagle]

What psi were you running?

 

[6literEat'r]

13pounds..gonna put ANOTHER slug in, and switch to e85

 

[6literEat'r]

possibly a tune to blame? idk, car was "suppost" to be on a "safe" tune..

 

[Eagle]

The plugs should have shown signs of fueling issues... which is likely your issue here...

 

[6literEat'r]

Well..
2 for motherfucking 2..... engines comin out