fmic issues (missfire)

[Perpetr8n]

hi everybody, i've been having trouble with my new front mount inter cooler, its the CXRacing brand. it was the first mod ive ever done to my car. boy dose it run cool now! BUT... ever since i had it installed it would continuously missfire when i step on the throttle to much, if floored from a dead stop the missfires would start around 2500-3000 rpm and end around 5000 rpm. when its really cold outside when i floor it is unable to pass 40 mph, i have to let off on the throttle to accelerate, and lately i have been getting around 11 mpg and 12mpg, far less than i was getting before the fmic. thinking it was a boost leak at first i took it to a performance shop to check it out and repair it, but it was 10 to 15 minutes away, and by the time i got it out there it stopped missing completely . they fixed the leaks anyway but when i let the engine cool it starts missing again( so its time sensitive i guess, after about 15 minutes it "cures" itself ) . my stock boost gauge is a steady rise like normal, so it dosnt look like it has any problem filling the large intercooler. i've took it to many mechanics since its "modified" theres no allot willing to help me and the ones that are, are too far away to show the problem. since then i've replaced spark plug wires and ran injector cleaner all the way through without even the slightest improvement.
any ideas are appreciated, thanks in advance.

 

[axloverstreet]

check all you silicone couplers and make sure all you T clamps are tight, i dont have a front mount, but with my side mount one of my couplers werent tight and it would cut out and missfire really bad, as soon as i replaced the hose clamp it was good.

 

[92_talon_awd]

Boost leak test. Sounds like you have a leak somewhere which would explain the misfires and the problem of running way too rich. I know you said the mechanics looked at it but in my experience, if you want something done right you need to do it yourself. Except for transmissions, send those to shep

 

[LandoAWD]

1. Get a real boost gauge
2. BLT the car (as suggested above)
3. Report back

 

[chico904]

Just curious as to what this "performance shop" said they did and how much they charged. Also, when I got my FMIC Itightened down everything super tight. After a week, I had the same exact problem you did. It just ended up being me having to go around and tighten all the t-bolt clamps again, its been fine ever since. As stated before, definitely do a BLT, and before you do that go and retighten all those t bolt clamps as I am pretty sure that will be your problem. Also check where the UICP connects to the throttle body, as this is a very common spot for a boost leak. Make sure it is tight, and possibly put a thin bead of silicon around it.

 

[Perpetr8n]

so it seems everybody thinks its a boost leak, i would think that even on the stock boost gauge, no matter how inaccurate, should jump maybe a little bit (in which it dosnt at all) or not be able to reach full boost, in which it can, while its missfiring. the shop i took it to was a "supershop" in which dose all kinds of turbo work. he told me he used a smoker and found and fixed a few big leaks, but of coarse i couldn't see if it helped cause my enginge was already warm and stopped missing, but that night it started missing just as bad as before, now i would think if it were a leak it would have helped a little bit, unless the leaks opened back up to how big they were before, dose this happen?
i have a friend that told me that i might need to get my ecu "flashed" so that it can read the extra air im adding to the engine, have any of you had to do this? or a bad maf Sensor, any easy ways of testing this?

 

[nuclearr]

Due to expansion couplers shrink and expand differently than aluminum and will some times work their way lose so I would recheck. On my stock side mount on my 2g did the same thing turns out the upper intake piping came lose behind the filter box (becase the prevous owner got arested in it and it was towed and the tow truck operator crushed/bent the intercooler knocking the pipe off.

 

[kahl23]

The stock boost gauge is complete sh!t, it doesn't measure actual pressure, just what the ECU thinks there should be. Don't rely on it, it is completely worthless. Reflashing the ECU is unnecessary, while some more modern cars are easily thrown off by increases in airflow, DSMs are not. To be honest, your intercooler isn't increasing airflow at all, it's simply more efficient at cooling the compressed air from the turbo. You won't really need any form of fuel management until you increase the amount of air going into the engine, either by pumping up the boost, getting a larger turbo, etc. Go to home depot and get the things needed to make a boost leak tester. Unless you stood looking over the shoulder of whoever worked on your car while it was at the shop, you have no idea what they actually did to it. It's very possible they missed a few leaks. So I guess what I just told you is a more wordy version of what Lando said, get a real boost gauge, to a BLT yourself, and report back.

 

[Perpetr8n]

ok that makes alot of scene. so why do u think it eventually stops after 10 minutes? well either way i will check it for leaks and get that boost gauge that is sitting in my room finally installed . thanks for all the help