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Old 03-30-2013, 02:01 PM   #1
Whoa!ShutItDown
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Default Bog, pop sound...misfire?

For the past few weeks my car has been bogging down followed by a pop or two in the exhaust (sounds like its coming from the downpipe area) while a little under moderate throttle. If I go from a stop, shift into second at 3500, and give it a little more gas so the turbo spoils up a little quicker right as the clutch is almost fully engaged, it will bog and chug/jerk a few times with a few exhaust pops. The boost gauge shoots up to 10 or 15psi when the pop happens, its only a split second. But it still pulls great once it gets over the stumbling

I have 124k miles, 16gxt, dw750s, walbro 255, tgv deletes, tomei 4-1 manifold with catless up pipe, fully catless 3in, gimmick inlet, Cobb sri, ebay big tmic, gs 3port bcs. Tuned at Innovative Tuning around 102k, 282whp 264wtq @19psi.

Now here's where you question why I'm even posting this. The 3 bolt up pipe gasket has a light leak, I hit full boost like 75% of the time. And the gimmick inlet has horrible fitment at the turbo, one side goes on farther then normal and the other side was on a little more then half way....when it was tuned 22k miles ago. Now it might be leaking on that side, I can't see from the bottom, but its moved scary close to the edge.

New plugs and fuel filter this week, new Cobb filter a month ago, and rotella t6 changed every 5-6k. I plan on doing the exhaust gaskets within the next month, and gonna try to push the inlet back on today or tomorrow, hopefully it doesn't pop off when I loosen the tbolt. I'll be getting a perrin soon
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Old 03-31-2013, 02:51 PM   #2
Sickvanbro
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Do you have new coil packs installed ? A gasket leak wouldn't sustain boost at the top end , so it's not that problem
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Old 03-31-2013, 05:03 PM   #3
Uncle Scotty
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sounds like a tuning issue...or maybe bad plugs
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Old 03-31-2013, 06:33 PM   #4
Whoa!ShutItDown
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I just replaced the plugs with BKR7E's since I was tuned on them. Also checked the coils which appeared good. The inlet is closer to the edge then when I posted this, I think its leaking underneath. I dont think its the tune because I didnt have the problem for awhile. I didnt do anything under the hood over the winter (except oil changes) so I didnt notice the inlet was working itself off until a few months ago, which is around the time this started happening. So I guess my question now is does it sound like the unmetered air could be my problem?
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Old 03-31-2013, 06:42 PM   #5
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Quote:
Originally Posted by Whoa!ShutItDown View Post
I just replaced the plugs with BKR7E's since I was tuned on them. Also checked the coils which appeared good. The inlet is closer to the edge then when I posted this, I think its leaking underneath. I dont think its the tune because I didnt have the problem for awhile. I didnt do anything under the hood over the winter (except oil changes) so I didnt notice the inlet was working itself off until a few months ago, which is around the time this started happening. So I guess my question now is does it sound like the unmetered air could be my problem?


yeah....and if ya keep beating on it when its ****ed up like this it will blow up

buying 'gimic' parts is asking for a new motor
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Old 04-01-2013, 08:52 PM   #6
Whoa!ShutItDown
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Well I took the t-bolt clamp off the Gimmick inlet, and it had about 1cm left before it was off the turbo, after seeing it with the clamp off I dont think it was leaking. I pushed it farther onto the turbo and took it for a ride, problem still exists. Im not sure where to go from here. Im at 124k miles and the only sensors Ive replaced are both o2's. I cleaned the MAF probably about 10k miles ago and didnt notice a difference. It has never flashed or thrown a CEL.

In my previous post I said this started happening a few months ago, I just figured it was the combination of the minor exhaust leak and needing new plugs. Until a few weeks ago I only experienced the bogging. On my way home from work after driving about a mile the bogging got much worse and was followed with the popping. Any thoughts are appreciated


Edit: I got into a minor accident right before this started happening (rear ended an old woman who slammed her brakes the moment the light turned yellow, i looked up and saw it turn red...) I didnt think of mentioning it until I read about a MAF being broken from an accident. So Im thinking its my MAF or front o2, when I replaced the front o2 only Bosch was available and Ive heard bad things about their longevity.

Last edited by Whoa!ShutItDown; 04-01-2013 at 10:07 PM.
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Old 04-07-2013, 10:14 PM   #7
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Today I finally got a CEL, p0030, HO2S heater control circuit bank 1 sensor 1. My front o2 is a Bosch cuz Denso wasnt available locally and I needed it asap when it died 2 years ago. Not much on this forum about that code by itself, one guy said its common from an exhaust leak. I ordered all new exhaust gaskets right before it appeared so they should be here and installed within a week. I also read its a random misfire, or possibly a short somewhere. Before the CEL appeared I was looking into PCV issues because I have alot of blow by built up on my short block where the PCV "T" is, I found a post on another forum with someone describing my hesitation/popping issue, they had 3 CEL's one of which was PCV related. Ill try to keep this updated for anyone else that has this problem, Im thinking its the exhaust gasket now
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Old 04-07-2013, 10:21 PM   #8
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d000000000000d...take the front covers off and check yer timing....it may have skipped a tooth or 2
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Old 04-09-2013, 05:47 PM   #9
Whoa!ShutItDown
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woooooooooooooooowwwwwww......it was a dirty MAF from the insane blow by caused by my bad PCV. When I cleaned it in the fall it was the first time being cleaned in over 100k and it didnt look any different afterwards, this time it had a thick layer of crud on one side. Now the hunt is on the the actual PCV and not the brass fitting that goes to the intake manifold
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Old 04-18-2013, 10:25 PM   #10
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Well cleaning the MAF worked for about a day. I checked the CPS and it had quite a bit of metal dust on it, but cleaning it didnt do anything. Then I figured it must be the 3 bolt gasket for the up pipe so I replaced that and the manifold to head gaskets. Also discovered the bracket that holds the turbo in place was loose, which allowed it to move enough to destroy the old 3 bolt gasket. So all of that was fixed, still sputters and pops. AAANNDDD the front o2 sensor wires were rubbing on the body, 2 were exposed and mostly corroded. I couldnt get a new one at that point since it was 10pm, so I taped the 2 wires individually and then all as one. Ran a little better due to fixed gaskets, but you guessed it, not the cause. Did the PCV also, nope.

On my way for a new Denso o2 sensor I stopped for gas, started driving and cel started flashing, it was a very slight uphill incline and I was driving slow/lightly. So I unplugged the o2 and continued driving, cel came back solid. Got the new Denso installed, drives much better, but still sputters and pops. It idles good, but you can hear a misfire when revving it up. Sounds like somethings missing in the exhaust sound, like only 3 cylinders firing. But no cel. When I first pulled away to test the o2, I went WOT at about 3k in 2nd, it didnt do much for how long I had my foot down, then as the turbo started to build the cel started flashing. I immediately stopped and turned around in fear of it going away before I drive the 1/2 mile back....and of course it went off and nothing showed in the scanner.

So now ive done the following with no signs of getting better:
fuel filter
spark plugs
checked coils and harness
cleaned cps
cleaned maf
checked boost/vacuum hoses
front o2
PCV
bottle of techron
seafoam through vacuum (seemed smoother)


I should have time to check the knock sensor, double check the coils/harness, and check the timing tomorrow. I also have an IACV gasket so I can clean that too. Any suggestions are still appreciated. Im thinking its related to the minor fender bender I got it (I rear ended someone), may have knocked something loose. Oil and coolant look good, no oil burning in the exhaust. Although I discovered the oil reutrn from the turbo is leaking a little bit
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Old 04-19-2013, 10:12 AM   #11
quazimoto
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Old 05-30-2013, 11:01 AM   #12
Whoa!ShutItDown
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Finally found my problems. I bought a new set of DW750s cuz it had symptoms of a sticking injector, thought it helped but it sounded like a cylinder wasn't firing so I didn't even test drive it. I changed the plugs, all were black and wet, didn't help. I was out of leads so I started checking everything again, eventually got back around to pulling the plugs and found the cylinder 3 plug was mint with a light gas smell while the others were black and soaked. The resistance of that injector ground was much higher then the others so I started pulling the tape and loom off and found two wires twisted together and taped up. After a few minutes I realized that used to be the plug for the pcv check that gets deleted with an aftermarket inlet. It had plenty of tape around it so I don't see how it was interfering with the completely intact injector ground wire, but taping it all up fixed that major issue.

Then for some reason I decided to check the front o2 plug to see what it was giving, 12v sometimes, 8v others, and even 0v a bunch of times. Came to the conclusion it must be the main relay so I ordered a new one through the dealer (3 chain stores told me I was wrong, that part doesn't exist, and it must be something else). I decided to break the old one open, sure enough the contacts for one side had tiny melted spots. So its finally solved. Thanks to all who replied!
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