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misfire or something else?

Old Feb 25, 2010 | 01:25 AM
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I need some help here. Recently I noticed that at wot, when the turbo kicks in, the car stutters/hesitates about every half-second to second. My first thoughts were that it was due to one or more of the coil packs going bad and causing the engine to misfire. What confused me was that no cel had come on. So today I went wot a bunch of times coming home from work to see if it needed a little more persuasion, because I was planning on checking what cylinder/cylinders it was coming from with my scan tool. So far there's still no cel. The only other possibilities I can think of is maybe the fuel pump or injectors going bad?? Any help would be great. Thanks in advance!
 
Old Feb 25, 2010 | 03:35 AM
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Do you have access to VagCom? I've heard of this being an air/fuel ratio issue before, maybe you're getting fuel cuts? I don't know exactly where in cali you are, but if it's been cold when you're going wot, you could be drawing more air than the ecu can shoot fuel at so it causes it to cut out. Maybe? I'm not quite as knowledgeable with the 1.8's so I could be wrong.

If it is still fairly warm where you are (I've only ever heard of a turbo motor getting these fuel cuts when the temperature is down in the 20*F range) so if you're not seeing temps below 35 or so, then I would rule this out and stick with a bad injector or something.

Good luck!
 
Old Feb 25, 2010 | 11:33 AM
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Originally Posted by A4Cragman
Do you have access to VagCom? I've heard of this being an air/fuel ratio issue before, maybe you're getting fuel cuts? I don't know exactly where in cali you are, but if it's been cold when you're going wot, you could be drawing more air than the ecu can shoot fuel at so it causes it to cut out. Maybe? I'm not quite as knowledgeable with the 1.8's so I could be wrong.

If it is still fairly warm where you are (I've only ever heard of a turbo motor getting these fuel cuts when the temperature is down in the 20*F range) so if you're not seeing temps below 35 or so, then I would rule this out and stick with a bad injector or something.

Good luck!
All I have is my basic code scanner actually. It's not cold enough for it to be an air problem, but I have a k&n filter so I don't know if that could have something to do with it. So this does sound like a fuel problem then? Maybe I should start doing some fuel injector treatments to see if that will help?
 
Old Feb 25, 2010 | 11:58 AM
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Well, first, try cleaning your MAF.
 
Old Feb 25, 2010 | 12:50 PM
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Originally Posted by dragonrage
Well, first, try cleaning your MAF.
Yeah, I didn't think about that. I never really looked at it before. Do I have to take off the top of the airbox in order to get to it? It doesn't look like there's enough room to pull it out through the hole in the top. I just went to look at it at my break. Thanks.
 
Old Feb 25, 2010 | 12:52 PM
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+1 to the maf. K&N intake filter oil has a nasty habit of coating the maf which can throw off air readings and make all sorts of issues. The injector treatments arent a bad idea to start off with, certainly cheaper than a new injector. I recommend RedLine's fuel treatment, I noticed a bigger difference running that through my fuel system than I did running seafoam through it. Seafoam does a great job in the crankcase and vac system, but RedLine is better for the fuel system IMHO. A good treatment of all three components isn't a wholly bad idea though, I know you just put this motor in so maybe its a little gunked up and just needs some TLC.
 
Old Feb 25, 2010 | 01:25 PM
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I don't bother taking out the MAF sensor when I clean it. I just clean it in place.
 
Old Feb 25, 2010 | 02:42 PM
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Ok, so what's the best way to clean it out with. Just blowing into it, or blowing it with an air compressor? Or is there some special cleaner you can spray on it?
 
Old Feb 25, 2010 | 03:02 PM
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You can buy MAF cleaner at any auto parts store, just get some of that, spray it in on the sensor and let it dry. Don't touch it though, its a very sensitive unit so just spray it and leave it.
 
Old Feb 25, 2010 | 04:02 PM
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Ok, I'll go pick up that maf cleaner as soon as I can. I'll make sure to post up the results afterwards. Thanks for all the help!
 

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