strange miss under boost STS kit
strange miss under boost STS kit My car has a STS setup on it and i'm now getting a miss under boost. The problems all started last monday when it rained here. I know i sucked up some water cause I got a maf error (we had a lot of flooding). Let everything dry out and the next day the car was fine.
Wednesday the car started to miss under boost, problem got worse on thursday and friday. On sat it was missing during normal driving too. I swapped the autolite 103's for some NGK TR6's. Gapped them to .030, old autolites were .035. That solved the normal driving miss, but it still misses under boost. At part throttle boost it will miss less often, but under WOT it will miss very bad, sounds like the spark is getting blown out.
So far i've swapped, o2's, plugs, wires and maf. Does anyone have any other suggestions. Could I gap the plugs less than .030. I've only run into these sorts of problems when running higher boost (12+ psi) on other cars i've owned.
Wednesday the car started to miss under boost, problem got worse on thursday and friday. On sat it was missing during normal driving too. I swapped the autolite 103's for some NGK TR6's. Gapped them to .030, old autolites were .035. That solved the normal driving miss, but it still misses under boost. At part throttle boost it will miss less often, but under WOT it will miss very bad, sounds like the spark is getting blown out.
So far i've swapped, o2's, plugs, wires and maf. Does anyone have any other suggestions. Could I gap the plugs less than .030. I've only run into these sorts of problems when running higher boost (12+ psi) on other cars i've owned.
12 Second Truck Club
Joined: Feb 2002
Posts: 5,574
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From: Sacramento, CA
Is there an intercooler on this car? Have you cleaned out ALL of the piping?
I had the same problem on my truck and I had a **** ton of water still in the intercooler and there was some still trapped in the piping.
Could have shorted the MAF too?
I had the same problem on my truck and I had a **** ton of water still in the intercooler and there was some still trapped in the piping.
Could have shorted the MAF too?
miss is random, I checked the pipes when I had the car on the lift today and I didn't see or feel any water in them. No intercooler on the car yet.
How can I check for a coil pack ground issue?
How can I check for a coil pack ground issue?
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Originally Posted by bradyb
clean your MAF too, take it out and spray it with parts cleaner. Did you have the water proof precharger over your filter?
I'll data log it again tonight to check for the missfire.
10 Second Club
Joined: Apr 2002
Posts: 1,755
Likes: 2
From: Cincinnati, Ohio
When I was trying to diagnose my mis-fire the data also showed a mis-fire on two cylinders (though I only had 1 bad coil). I guess its just not that precise so it was showing a miss over two cylinders. The really weird thing was that the bad coil was one cylinder past the later one in the firing order showing the mis-fire. So the culprit cylinder was not one of the ones that the data log showed. It took me quite awhile to figure out because of this.
10 Second Club
Joined: Apr 2002
Posts: 1,755
Likes: 2
From: Cincinnati, Ohio
Don't leave cylinder 4 out of the coil swapping (trailing cylinder in the firing order). If your experience is like mine was that could be the one. Of course also swap 5 & 6. At least that will rule out the coils.
Ok, swapped coil packs, 2-4, 6-8, 1-3, 5-7.... still have the exact same miss fire 
I guess swapping injectors comes next, then swapping the ECU. After that i'm SOL I guess. Man this is frustrating! I just wanna experience boost again!
I guess swapping injectors comes next, then swapping the ECU. After that i'm SOL I guess. Man this is frustrating! I just wanna experience boost again!
10 Second Club
Joined: Apr 2002
Posts: 1,755
Likes: 2
From: Cincinnati, Ohio
So the miss stayed on the same cylinders as before I assume. Did you try the switching the wires around too? I would put the ECU way down on the list of probable causes, very unlikely.
i'll try the plugs and wires tonight when I get home. I'm trying to change only one thing at a time so that I can narrow down the problem. The car drives great as long as I don't boost.
I really hope this is something stupid and simple. Last thing I want to do is pull valvetrain crap.
I'm gonna swap a few plugs and wires and also regap some of them to .025 to see if that clears up the problem. It really feels like spark blow out.
I really hope this is something stupid and simple. Last thing I want to do is pull valvetrain crap.
I'm gonna swap a few plugs and wires and also regap some of them to .025 to see if that clears up the problem. It really feels like spark blow out.
Last edited by Zombie; Jan 12, 2005 at 10:48 AM.
