What's wrong with my car: Round 2

peepsalot

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Black 03 MSP
Alright I'd like to thank the participants in round one of "What's wrong with my car". The winner, Genius, walked away with one fabulous (picture of a) CHOCOLATE TROPHY!
The stakes will be even higher in this round so put on your thinking caps and let's get ready to play "WHAT'S WRONG WITH MY CAR?"

OK first some background info. I have a BEGI FMIC w/ Greddy type S BOV, venting to atmosphere, stock boost of ~6psi, MAF on IC->Throttlebody pipe. GHL downpipe, AEM CAI being used as SRI. Currently no fuel or spark management is being run.
My problem is this: When accelerating WOT, If I quickly shift into the next gear and floor it, my car stumbles continously until I let off the throttle and give it a second to recover. During this time, it is completely rich, bottoming out my wideband at 9.6. If I shift slower and give it a moment, and then ease into flooring it, then the car will behave.

For bonus points: A second problem I have been having, possibly related to the first. If I accelerate at partial throttle, keeping my boost gauge around 0, at around 4000rpm, my car hits a wall and just backs down. This is similar to descriptions I have heard of fuel cut, but the strange thing is I only have this problem at partial throttle, where I would be presumably taking in less air than WOT.

Note: Until recently I had the BOV recirculating, and the MAF in it's normal place. Even with that setup I had the second problem mentioned. I am not sure if the first problem existed with that setup, because I hadn't pushed it very hard, but I think I remember it happening at least once.
 
I'm running about the same setup as you and occasionaly while i'm in the 4000 rpm range and the car starts to see a little boost the ecu will s*** on itself for a second as well. I think you can blame mazda for this one
 
Agh, wtf. Goddamit mazda. I should just get a standalone.

BTW, when my car is runnning correctly, it pulls very well, I'm pretty happy with this setup for the most part.
 
jersey_emt said:
Try tightening the BOV to fix #1
OK, will do. I kinda figured I might have to adjust the BOV some, but I thought that with a MAF setup like this it wouldn't affect drivability much.
 
jurgs01 said:
Maybe your plastic MAF being on the "hot" side got too hot and is malfunctioning.

It's on the cold side of the intercooler. Other people run a similar setup without problems.
 
I just think the chances of something that you modify failing are higher than the chances of something that you haven't. Logical troubleshooting would lead you to check all of your modifications that might have caused the problem first, then check other possible causes.
 
how tight is tight? my greddy has 4 threads sticking up. i cranked it down a lot.

do u have a CEL light?

i would recirculate the bov if you can and move the maf to the intake --> turbo pipe
 
Well, looks like it really was my BOV. I guess it was leaking under boost. I had it down to a couple threads past the locknut, and I thought that was good enough. Now I have it flush with the locknut and it runs much better. How do I know if it's too tight?
 
CustomMSP, the CEL I got the other night was for "O2 sensor slow to react", P0133 I think. I was using my wideband's narrowband simulator to go to the car since I thought it would be more accurate. Guess the car didn't like that. I don't think this had anything to do with my problems listed here though. I guess I could go loosen my BOV again to confirm that it's the source of my problem if anyone cares.
 
peepsalot said:
Well, looks like it really was my BOV. I guess it was leaking under boost. I had it down to a couple threads past the locknut, and I thought that was good enough. Now I have it flush with the locknut and it runs much better. How do I know if it's too tight?

You know it's too tight when you are getting a huge turkey sound.
 
Dammit. Well I certainly have crazy turkeys now. I'll try loosening it some more, but it seems like there is no compromise, either turkey or really bad performance. Should I have absolutely no turkey, or just try to minimize it? I heard that with only a single BOV(not dual setup) that most people still have turkey.
 

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