Fouling plugs above 5000rpm
03-11-05, 10:24 AM
#1
Fouling plugs above 5000rpm
Here is my setup. Just got done break in, with 2000 miles, Rotary aviation seals.
Series five turbo two, completely stock other than
Streetport
TID/conefilter
Aftermarket rad
oil cooler lines
FCD.
Above 5000rpm the car hits a wall and hesitates, boost starts to die off, and it won't go past 6k rpm it seems like if I try to push it past that, it just fouls the plugs. They have black soot on them (i'll take pictures tonight. I just replaced the plugs.) I failed emissions earlier that day because I was running a hair rich, I think that's due to the fouled plugs or some other, as of yet, unidentified issue.
Is an S-afc going to be a bandaid to this issue?
Is a stock downpipe/exhaust going to restrict the street port to the point that the engine performance degrades? (i.e. more air going in then can get out?)
Could it just be a bad O2 sensor? I plan on replacing this tonight, because I ran this 02 sensor on the blown motor prior to the rebuild so I'd imagine it's pretty dirty.
Series five turbo two, completely stock other than
Streetport
TID/conefilter
Aftermarket rad
oil cooler lines
FCD.
Above 5000rpm the car hits a wall and hesitates, boost starts to die off, and it won't go past 6k rpm it seems like if I try to push it past that, it just fouls the plugs. They have black soot on them (i'll take pictures tonight. I just replaced the plugs.) I failed emissions earlier that day because I was running a hair rich, I think that's due to the fouled plugs or some other, as of yet, unidentified issue.
Is an S-afc going to be a bandaid to this issue?
Is a stock downpipe/exhaust going to restrict the street port to the point that the engine performance degrades? (i.e. more air going in then can get out?)
Could it just be a bad O2 sensor? I plan on replacing this tonight, because I ran this 02 sensor on the blown motor prior to the rebuild so I'd imagine it's pretty dirty.
03-11-05, 10:54 AM
#4
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If it's fouling the plugs then it's running too rich, which doesn't really make sense at all. Check your injectors to make sure they're working properly, might check grounds and such.
03-11-05, 11:39 AM
#7
Ah yes, There is a walbro pump there, forgot to mention that.
There are two cats? I have a down pipe, midpipe, cat, then the stock cat-back, just one catalytic converter. I assumed it was stock (looks stock anyway). I've never had an s5 t2 before so I have no idea what should be stock on the exhaust. Generally in my experience if it looks old, rusted, cast, has heat shields on it, It's probably stock.
There are two cats? I have a down pipe, midpipe, cat, then the stock cat-back, just one catalytic converter. I assumed it was stock (looks stock anyway). I've never had an s5 t2 before so I have no idea what should be stock on the exhaust. Generally in my experience if it looks old, rusted, cast, has heat shields on it, It's probably stock.
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03-11-05, 11:50 AM
#8
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I would say that a S-AFC wuuld help. If you get a S-AFC dont max out your injectors, you dont wanna exceed about 80% duty cycle. You should probably go on and get a fuel pump, walbro 255's are good.
03-11-05, 12:07 PM
#9
FYI-The factory exhaust has a precat in the dp, and the factory main cat covers almost the entire length from the midpipe to the "Y". Just checking to see if the cat could be semi clogged, and not allowing the exhaust to flow properly.
Also, there is probably somthing causing the car to run rich, and the O2 sensor just monitors the condition.
Also, there is probably somthing causing the car to run rich, and the O2 sensor just monitors the condition.
Last edited by Turbonut; 03-11-05 at 12:13 PM.
03-11-05, 01:34 PM
#11
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Probably not, but i'm not certain.
I think Turbonut is probably heading the right direction about the clogged cat. That could cause a rich condition.
Do you have still have the Airpump installed?
I think Turbonut is probably heading the right direction about the clogged cat. That could cause a rich condition.
Do you have still have the Airpump installed?
03-11-05, 01:49 PM
#12
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Vac leaks make you run lean, because there's unmetered air getting into the engine. Probably not your problem. 
When was the last time the plugs were changed? Sure your FCD is working properly and not set a little incorrectly so that you're hitting fuel cut (I'd imagine your setup would creep a hair bit, so it's possible). Sometimes you have to adjust them.
When was the last time the plugs were changed? Sure your FCD is working properly and not set a little incorrectly so that you're hitting fuel cut (I'd imagine your setup would creep a hair bit, so it's possible). Sometimes you have to adjust them.
03-11-05, 03:33 PM
#13
Originally Posted by SonicRaT
Vac leaks make you run lean, because there's unmetered air getting into the engine. Probably not your problem. When was the last time the plugs were changed? Sure your FCD is working properly and not set a little incorrectly so that you're hitting fuel cut (I'd imagine your setup would creep a hair bit, so it's possible). Sometimes you have to adjust them.
When was the last time the plugs were changed? Sure your FCD is working properly and not set a little incorrectly so that you're hitting fuel cut (I'd imagine your setup would creep a hair bit, so it's possible). Sometimes you have to adjust them.It's a Racing Beat FCD, I have all stock emissions equipment (including the air pump) in place, but I assume I've got an aftermarket catalytic converter. I didn't do the exhaust work, the guy before me had it all done.
The last time they were changed was at the rebuild.
03-11-05, 05:06 PM
#15
Originally Posted by Parastie
You need to check and see if the Airpipe that goes from the ACV to the cat is still connected. If it's not then your cat is probably clogged.
03-11-05, 06:05 PM
#18
Former Moderator. RIP Icemark.
Hmmm, I was expecting both trailing and leading to be '9EQ. I have seen simular fouling on people using '9EQs as leading plugs, and using too big of secondaries.
03-12-05, 08:15 AM
#22
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do u have an aftermarket boost gauge?
how many lb's of boost are u at when u "hit" the wall?
Do u hit the "wall" when doin WOT runs?
can u go till redline in gear at partial throttle?
how many lb's of boost are u at when u "hit" the wall?
Do u hit the "wall" when doin WOT runs?
can u go till redline in gear at partial throttle?
03-12-05, 08:19 AM
#23
Yes, in my earlier post, i'm running a stock 8.6lbs of boost, when I hit the wall at 5000 rpm boost dips down to 6psi and stops building while it slowly bleeds off.
It happens under full or partial throttle.
I think it's totally possible that it's a clogged catalytic converter.
It happens under full or partial throttle.
I think it's totally possible that it's a clogged catalytic converter.
03-12-05, 08:32 AM
#24
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U can try opening the exhaust temporarily and hanging it off to one side, and try a run with "open exhaust" to see if it helps
I had a similar problem in my skyline GTR... it was driving me crazy, I changed the plugs, I changed the fuel filter, I had the injectors prof. cleaned, cleaned the maf's, opened and refitted all teh IC pipes...hell I even changed the fuel pump to a MKIV supra's... none of it helped...
it turned out to be the coil packs in the end
u can try swapping with a buddy of yours to see if that helps...
I had a similar problem in my skyline GTR... it was driving me crazy, I changed the plugs, I changed the fuel filter, I had the injectors prof. cleaned, cleaned the maf's, opened and refitted all teh IC pipes...hell I even changed the fuel pump to a MKIV supra's... none of it helped...
it turned out to be the coil packs in the end
u can try swapping with a buddy of yours to see if that helps...
Last edited by Ottoman; 03-12-05 at 08:35 AM.