Backfire repeatedly

[ZBninja]

I'm running a corksport FMIC, Tback, and CP-E standback. Around 3.5k and up i get this stuttering issue with backfire. I've changed my spark plugs and check over all piping for leaks, and I also cleaned my MAF after i got a P0102 code.

Any help would be great to figure this out.

[zinger002]

stock bov?

[bova80]

do you have upgraded fuelpump internals? with all those mods you definitely need them.

[ZBninja]

I don't think that 17.9 psi is too much for the stock fuel pump but I will check that. If i set it to 11.9 it almost makes it threw to redline before it stutters again.(for the most part). I got a p2177 System Too Lean off Idle (Bank 1) tonight so now I'm confused. So any other ideas will be nice. and yes i have a aftermarket BOV and have tried both vented and recurc. Thanks for any more help.

[USAFVMI08]

If you have a dash hawk or Cobb AP, check your fuel pressure in the high RPMs. Anything below 1200psi is bad bad bad.

[ZBninja]

I think i can read fuel pressure with the standback. I will check tomarrow.

[bova80]

if it feels like you are hitting a wall and then it keeps going then that is fuel cut and you'll probably most likely need to upgrade those fuel pump internals. especially as the weather starts to get colder you'll get it more and more since you'll have more air coming in.

[ZBninja]

One question before I head out to check the fuel pressures: I am currently running on low boost which is only 11.9 psi and it still studders when I go WOT. If it were a fuel issue I would imagine that would only happen under high boost applications? I'm willing to try about anything that gets suggested at this point though! Thanks for the help so far, guys! I'll keep ya updated!

[bova80]

are you sure the gap on your spark plugs is correct? it should be less than .032

[Mazda3000GT]

From my experience with tuning from other cars, when it backfires 9 times out of 10 you're running rich. So how much of the fuel goes unburnt. When it sputters, it's ignition; spark plugs and wires.

[ZBninja]

Great suggestions. guys! I'm extremely busy on Wednesdays so I won't get to check that until Thursday. I'll pull the plugs out and check the gap with a feeler gauge. I can try to get specs and OHM out the coils but they sit right on the plugs so that eliminates wires. This all started a little while after the FMIC. I had the uncirc the BOV due to the piping and a while after that it started sputtering. Otherwise I haven't changed anything...odd. Thanks again! I'll post when I get those tests done!

[Mazda3000GT]

Great suggestions. guys! I'm extremely busy on Wednesdays so I won't get to check that until Thursday. I'll pull the plugs out and check the gap with a feeler gauge. I can try to get specs and OHM out the coils but they sit right on the plugs so that eliminates wires. This all started a little while after the FMIC. I had the uncirc the BOV due to the piping and a while after that it started sputtering. Otherwise I haven't changed anything...odd. Thanks again! I'll post when I get those tests done!

Then boost leak somewhere is causing your problem!! Recirculation type bov is always recommended on cars running mass air sensor. The type that doesn't circulate the air is good for cars running speed density.

[bova80]

what kind of bov are you running? if its not meant to run vta then there is your problem, you could have a major leak on your hands, although it should be fine under boost since it would be closed.

[_MSprotegy]

ilke someone else said you need to upgrade your fuel pump internals with those mods especially with the FMIC. next check for leaks in your piping on your FMIC cuase sometimes ppl overlook things that might cause a leak.

[ZBninja]

I'm running 12 psi right now, and its doing it all the way through. I pressure tested the Intake and found leaks, so I fixed that. Then i repressurized it again and air was going threw my valve cover, and oil dipstick. Any ideas. PCV? Also the spark plugs are all gapped at 0.28.

[bova80]

where were you pressurizing it from? you want to do it on the inlet so you aren't pressurizing the valve cover through the breather valve that connects to the intake.

this was my makeshift pressure tester:

http://www.mzdspd.com/mzdspd/images/install/install19a.JPG

[ZBninja]

Yeah so funny story, I realized I was pressurizing the valve cover through the breather after I hooked up my little intake pressurizer one more time. I think Shaun and I got my problems figured out though! After fixing the boost leaks, we pulled the plugs back out. We found one with a large piece of ceramic missing, allowing it to spark to the side of the plug instead of the electrode. after we replaced that, the car is running great! Thanks for all the help and suggestions everybody! Next step: fuel pump internals!

[kevo26]

Yeah you don't need fuel pump internals unless you get a bigger turbo. I've got the corksport fmic kit, 3" TBE, forge BPV, Cobb AP tunned it to 19psi, and denso iridium IV24 plugs. I had back fire issues with the stock plugs switched them to the iridiums problem solved. If you switch out your fuel pump internals you will be running hella rich with out getting more air to it and the stock K04 is useless above 19psi and simply can't keep up with an upgraded fuel pumps demand for air. Some dude on another forum did his pump when the kit first came out before doing his turbo and did dyno testing with A/F ratios and it was way rich.