I will try and make a long story short from my last track outing late last year. Now I am trying to fix the problem but I'm totally stumped. The head gaskets were done a month before this and was running great up until the vacuum line came off the alky system. I really don't want take the heads off again.

So here it is:

The vacuum hose that goes to my 2 bar MAP sensor that runs my alky system had popped off. I made a run through 4 gears at WOT with no alky on a tune that relies on it. Massive lean condition and the IATs didn't move lower at all. 14-1 at the begging of a gear and 12.5-1 by 6K where I shift. Massive knock counts all through the run. Needless to say there was lots of detonation.

The bad:
Mechanical wise the headers tubes 2,3,4,5,6 and 8 get red hot and glow after 4 minutes of running and I have lost 2 HG of vacuum. It idles fine on its own after you open up the throttle blades to get the RPMs up.
It is running SUPER rich, plugs get wet with fuel after a few minutes of running…causing glowing headers.
It idles fine in open loop but goes to **** in closed loop where I have to shut it off as the headers are red-red.

The good:
Idles fine in open loop.
No knocking noises when at idle or blipping the gas.
No ticking from the valve train .
No coolant in the cylinders or the ground. Still in the rad.
Oil and filter were changed and checked out good, no metal on the oilpan magnet.
Oil pressure is solid.
Coolant temp is fine.
No puff puff from the valve cover breather indicating there is no blow by from the rings

Did a compression test.
Results in PSI:

#2 165 #1 175
#4 175 #3 175
#6 170 #5 175
#8 165 #7 170

Keep in mind this is an 8 year old 9:1 blower engine.

A leakdown test was done on the first 4 cylinders. The easy ones were done including one of the 165psi compression holes.
Results were 10 for all holes with no air escaping from the valves and a shade from the rings. To be expected from such an old motor.


From the logger I see:

Before lean ++ After lean
MAP 50-52 ++ 65-67
IAC 55 ++++maxed at 160
MAF air flow grams/sec
10-11+++ 16-17
Base pules widths
1.4-1.5 +++2.4-2.5
INJ DC
1 ++++1.6-1.7
The BLMs looked good from the few secs it went into closed loop. No codes either


Conclusion:

It is running way rich and the plugs were soaked in fuel. The PCM is seeing lots of air come in for some reason. The MAP is high (confirms loss of 2 hg on boost guage) and I *think* it thinks the car is under load and commanding fuel to equal the (wrongly calculated) air. That is one theory anyway but why??
Why this would happen right after it went lean at the track? I don't see how anything mechanical could cause this unless there is a leak somewhere that I am not seeing. It seems the engine is OK though.
With a vacuum leak I've always seen the BLMs go green for a lean condition (uncompensated air) which I am not getting this time around. No codes either and it doesn’t high idle like you have with most intake leaks. The BLMs look good for the few minutes I let it go closed loop. I looked for intake leaks, sprayed contact cleaner on the IAC and TPS connectors, cleaned the throttle body, reconnected the Crane box and a few other things. No dice.

Any ideas?? I am stumped and don’t want to pull the heads anytime soon. I am thinking a huge intake leak or a bunch of bad valves in a bunch of cylinders…bent pushrods??
People are pointing the finger at the old stand-by opti and to replace all the sensors. I think they are reading correctly and detonation wouldn’t kill a bunch of different sensors all at the same time.

 

Been a long time since I was up on everthing you wrote but sounds like it has learned a lot of rich settings you don't want. Have you tried disconnecting the battery to start the closed loop learn over again? Also, not sure but I think it gets hot because it's lean, not rich. Extra gas should cool it down not heat it up. Isn't your compression normal and within 8% of each other?

Hal

 

from what you're describing you definately have a LOT of unmetered air coming in somewhere. since the compression and leakdown check out I would put it either at bent pushrods, a couple of burnt/bent valves(unlikely since they still seal), or a popped intake gasket. maybe check all the vacuum lines for the intake to make sure none of those are cracked/broken. You're motor may not be totally toast, but it sounds like it may potentially be injured. Do you have any compression results from before the massive lean out? That would give you an idea of how bad the rings are in comparison to what they were. If it were me and not my d/d, I'd yank it and freshen it. After all it's 8 yrs old.

 

The unburnt fuel from the excessive rich condition gets into the headers and burns there thats what causes them to glow.

 

I've heard of the catalytic converter glowing from too much unburnt fuel but not the headers.

Hal

 

I've seen a few cars do it...mostly turbo cars on the dyno, but it never is a "good" thing. Usually it leads to a tuning session to lean it out a little, so you don't wash anything. Look really wicked in a blacked out dyno cell though!!

 

Do you have cats on this car? If so, then I would gut them because the rich mixture has most likely destroyed them and thats whats causing your headers to glow like that...

 

plugged cat?

 

That is what I am thinking. Lots of unmetered air. I don't have compression results from before and checked all the vacuum lines this week with no luck.
I hope it is the gasket. if not the heads come off.

 

The cats are long gone.

 

speaking of gaskets, I just looked really close at your first post, and the compression numbers. To me it's screaming rings or head gasket. You can have a sealing ring pop, and not break the seal for the coolant or the oil, in which case you wouldn't have any of those indicators. What you "may" hear on the other side would be a ever so slight hiss, coming out near those two cyls. just about all the time. But seeing as your numbers are not that far off from one another it can't be a large leak.....but any leak is bad. I would say pull the heads. It's probably going to be a head gasket, but you may find more damage in the valves....or you may have lifted the heads ever so slightly and now they may be warped.....I think you're going down-hill with every turn unfortunately..

 

I think I might have found the problem, I hope anyway.

While under the car I found one of the vacuum lines that goes to the opti was wiggling loose. As I tried to get the clip off the whole tab/bracket came off.
It is a shame. That opti has been great for 8 years.

 

I'm pretty sure that wouldn't do it. That vaccum line is too small to bring in that much air. I wouldn't go ditching the opti over it either. I'd rather be carefull cleaning off the engine and wait till it fails. I'm not even sure how wate could get into the opti anyway. It's pretty much a closed unit.

Hal

 

That is my worry too. The problem is it has to come off because the vacuum nipple on the opti cracked off. I don't think I can glue it back on. Maybe I can figure out a way to get that vacuum line back in there. It can't stay like this either way.

 

if you want to test that theory, put a bolt into the hose and see if your problem goes away, The line going to the opti from the intake is just to pull fresh air through to help eliminate the ozone area in there....the main killer of the optical sensor.

or you could just put your finger over the end of the hose and see what happens