Thread: Vacuum leak intercooler help, Can I pick your brains?

Alright. Currently have a genV blower on a 1" short stack intercooler. Car was running perfectly with normal fuel trims, normal vacuum, no missfires, raced a 2012 evo and won last night with 4 people in the car.... You get the picture right?

Anyways today it fired up fine no issues drove to work and everything is happy as a clam, even got to show off to a coworker at a stoplight. Get off of work and the car is pulling 40%+ positive fuel trims at idle with normal ~5% trims under load. WOT fueling is still locking in at 11.5 no problems. As soon as I let it drop to idle the thing wants to stall until it can pull the fuel trims to 50% again. It will idle basically normal with some missfiring and not perfectly even rpms. Wideband is agreeing with the fuel trims more or less.

Things I have eliminated
-Its not o2 sensor wideband is showing that everything is leveling out at 14.7 like it should
-Its not the maf or maf scaler, car is just as retarded with or without it plugged it
-Its not the map sensor, the readings agree with my boost / vacuum gauge so its ok
-All of the vacuum lines are connected and not leaking, Tested by unhooking and plugging the three ports on top of the blower as well as the LIM port.
-Its not the retarded genv pcv system as far as I can tell. No vacuum is being pulled on the crankcase and im running a breather so I have all of the pcv related ports plugged
-Only CEL came on AFTER the problem started. System too lean bank 1. My response? No **** I can tell.

My guess is vacuum leak somewhere between the blower, intercooler, and lim. I tried watching the wideband output while spraying brake cleaner everywhere along the edges but didn't notice any spikes. Should I take the time to pull the blower / intercooler off in the parking lot or should I be looking elsewhere for my issue?

The current plan is to pop the rails blower and intercooler off and reseal with grey rtv. Shouldent take more then 2 hours. Currently is sealed with grey rtv and garlock gaskets. (My guess is everyone will say that's the problem right there)

Garlock gaskets suck. Big time. I'd say try resealing it without a gasket just use RTV.

Ditto to what iceman just said, my ltft's were pegged at 16.4 at idle n I took out the garlocks n used strait copper rtv on top and below of the lim n problem solved. Maybe try brake cleaner, starting fluid while idle around the ic core, or sea foam if your blower n stuff is painted to see if bogging.

Pulled it apart. Took exactly 2 hours from hood up to hood down just like I thought. Didn't immediately see any failure but whatever. It started and ran for about 5 seconds so at least I didn't kill it. Ill test it for real tomorrow once the rtv sets up.

Ultra grey RTV with no gasket!

Final update. Supposed to get below freezing tonight and didn't want any uncured silicone to freeze so I started it up to warm the block up a bit. Ran pretty damn good. PCM is throwing tantrums though because of the horrific fuel trims it learned so it refuses to even try to idle below 1k rpm but at least this time its just because it goes so lean that it cant run. Should be fine once I clear the fuel trims with hp tuners im sure. Thanks again guys.

No need to clear the trims, when you took the SC off, you could've just disconnected the battery, lol.
: )

Car still runs like liquid **** down my legs... ONLY when it is at idle or no throttle. 40%+ fuel trims. I still cant find any damn leaks. I went through another entire can of brake kleen trying to find them. Is it even possible that its still a vacuum leak? Could it be leaking between the two halves of the intercooler? The thing is less then a year old. What I dont get is that it does it even with the maf unhooked. Typically when you are running a map sensor with a vacuum leak the car will just idle high (Unless its near a specific cylinder runner then that cylinder will missfire which mine is not) What am I missing here? Its almost like the injector offsets are muffed up badly but I haven't touched my tune in weeks

Figured it out, noticed the maf scaler was hot as a mofo while poking around. Turns out that it was outputting 0lbs of airflow at all times... no cel at all. Only time it set a cel was if I unhooked it. My guess is the pcm was smart enough to ignore the 0lbs under load but not smart enough while idling. My brain hurts. Anyways hooked the maf up directly and flashed the tune back to a non scaled maf table and the car runs like a dream again. All of that work for nothing. Oh well.