MSP bucking

[YouDontGnomeMe]

Sometimes when I'm hitting the gas slightly hard, when the RPM's get to around 3500-4000 (just after the turbo kicks in), the car will start bucking real hard. It does it mainly (especially) in cold temperatures, or just on real cool nights. Any ideas what would cause that? My sparks are less than a year old, so I don't think that's the cause...

 

[bwalt]

You are hitting fuel cut, or there's a leak post maf. Mods?

 

[YouDontGnomeMe]

Corksport CAI, that's it. I installed it a few months ago, so I haven't driven the car with the CAI in the winter (when the bucking was happening the most). I've got a Corksport Forge BPV on the way, as well as a Turbohoses SMIC/piping on the way. The top intercooler line has a problem; the nipple part that has the line running to the BPV was previously broken, the previous owner epoxyed it back on. Obviously the new piping will fix that, but I don't know if that has anything to do with it. I also suspect I have a vacuum leak, the car's thrown codes for running rich before, but it's been a while since it's thrown any codes. I don't know if any of those could be causing it.

Sorry for my lack of technicality lol. I'm an electrician, not a mechanic.

 

[bwalt]

Any leaks after the maf will mess up the signal and cause you to go pig rich. I would get those hoses looked after and see what happens. Make sure you reset the ecu as well.

 

[YouDontGnomeMe]

That's what I was thinking, that hopefully the new piping/BPV will solve everything. Just wasn't sure if there was anything else I needed to look at. Thanks! I'll keep things posted once I get everything and get it installed.

 

[josh182]

My car has been doing similar for the past two weeks. Get to full boost in 3rd gear and car is bucking real hard, its unbearable. so i did spark plugs, coils, tested a new MAF etc nothing helped, the code it brought up at first was for air fuel being too lean, went to a mechanic and they did some tests couldnt figure it out, cost me a pretty penny though. and now i blow a ton of gas out the exhaust! so now im running too rich.
Yesterday got another check engine light, got the code checked now its saying its the bank one reading too rich, but i dont think its the o2 causing the bucking, do you have anything similar to this?? im still searching for an answer, Mazda told me to replace the turbo hah.

 

[bwalt]

Good luck!

 

[YouDontGnomeMe]

That sounds kinda similar. I had a bank 1 code, and had to end up changing the O2 sensors and getting the cats replaced to fix it. I havent tried replacing the plug wires, nor taken the car to anyone. Its kinda hard to, since it's intermittent and only really does it in cool air. You should try checking your cats/O2 sensors.

 

[josh182]

yea, im trying to figure out if the o2 code came on since its now running so rich, or if thats causing the bucking, since ive done just about everything else to try to fix it.

Does yours struggle under a load, like going up hills or with a full vehicle?

 

[YouDontGnomeMe]

No, it doesn't seem to. The only other thing it does is it's had a loss in power since installing the CAI, which I'm hoping is caused/will be fixed by the things previously listed. But I don't seem to experience any problems under loads like you asked.

 

[josh182]

hmm, interesting. I gotta find a mechanic who knows turbos honestly hah, ive spoke to half a dozen mechanics and no one is too sure, but none of them work on turbos. Hopefully you figure it out. ill check on cat and o2s and see what it does. Good luck

 

[JDMazdaFamilia]

This happens to me too it'll buck then check engine will flash and I get a code for random misfire. Other times it happens when I'm driving normal, out of no where I'll feel loss of power, keep my foot on the gas and seconds later the car takes off like a rocket and kicks back

 

[JDMazdaFamilia]

I wonder if it's because I did a maf relocation and haven't tuned

 

[YouDontGnomeMe]

My check engine light doesnt come on after it bucks, I just need to let off the gas. Ive tried pushing thru it, but that doesnt work lol.

 

[bwlknsn91]

Are you guys havin idle problems as well?

 

[josh182]

Same for me, i get massive loss of power sometimes, let off gas usually.
And yes Idle problems always haha. going down to like 400 and getting ready to stall. sometimes at a light will go from 600-800 etc.
Today took my car out, still feels the loss of power but it wasnt really bucking just hesitates and loses power.

may disconnect battery to try a reset. That's helped with some of my friends cars with similar problems, but they are non turbo. any ideaS?

 

[YouDontGnomeMe]

It used to, it used to idle high and kinda stuttery. It doesnt seem to now.

 

[YouDontGnomeMe]

My car DOES seem to gently vibrate rather hard, if I'm at a stoplight or something. Like a gentle rocking. It's weird.

 

[josh182]

yea that's weird. the car vibrates at a stop, and it used to idle high? maybe hook it to a scanner and see what everything is reading. see what looks out of place
mine just almost stalls at a stop, going to a mechanic again today to bring some new research and see what he says ha.

 

[slowspeed]

These very same symptoms with the very same codes happened to my speed... It was the wastegate. It is, as you might know, tied into the vacuum system. If it is bad it leaks vacuum (poor idle/rich code), then during boost the pressure is leaking out instead of actuating the gate (boost spikes/fuel cut). I can't recall my specific search, but I imagine "wastegate" should work. I was able to find a simple procedure to figure out if it was bad, and the procedure to replace it (which was a b*tch I might add)... Hope this helped.