AAARRRRRGGGGGGG!!!!
Fraggle frikin snagglesnach!!! So, I'm still waiting for down pipes but the clamp fix in UT is holding. Apparently there was a worse leak there than I thought last post. Just the clamp has evened things out considerably. The change to the SPAL to 188 and 208 and the removal of the IPF lights on the bull bar have stabilized temperatures.
Last weekend I was down to the IAC and MAF as the only two things under the hood that haven't been replaced this year by factory Mitsu new parts.
I figured out the stumble/miss/off-idle/refuse to idle nightmare that would crop up occasionally after running the F/IC for several weeks to a month or two. Somehow the F/IC is horking with the ECM which is then screwing up the IAC. Don't ask me how, but I replicated the problem consistently. I originally though (and wrote) that it was garbageing up the ECM, but that's not the case. Even replacing the ECM doesn't fix the issue once if crops up. The behaviour is exaclty the same as if the IAC was bad. BTW, this triggers no codes.
The only way to resolve the issue is to reset the ECM (by unplugging from power for 30 minutes or so), and follow the FSM directions to set the IAC EXACTLY. Just resetting the ECM still leaves the IAC in some whacked out 'miss-adjustment'.
So, while continuing to test this problem, I pulled the F/IC. I left the wiring and put in the jumpers that AEM supplies to allow you to remove the F/IC box and still drive the vehicle. I've had it this way for a week and no issues have cropped up. I wanted to do this to confirm that I WASN'T actually seeing bad behavior from a IAC heading south. It shouldn't be since it's only two years old and a factory Mitsu part, but ....
I've had some strange behavior for several years which I was almost sure was the MAF. I also was seeing the exact same behavior on my little stock '97, so I swapped MAF units last year. The problem followed both vehicles. So, yea, I figured that both were having issues. I picked up a brand new Mitsu OEM MAF three months ago but I've put off installing it until last Saturday. Only change one part at a time. Test. Repeat. So, last Saturday I was down to the IAC and MAF. The new IAC isn't in yet so I swapped in the new MAF.
Yep. Bad MAF. <img src="/forums/images/graemlins/frown.gif" alt="" /> No CEL or pending codes, but it was definitely having issues. I can't tell if it was air flow, of BARO. I doubt very much its IAT. But, one of them or both are not working correctly. I suspect both because ...
... wait for it ...
EVERYTHING changed. <img src="/forums/images/graemlins/frown.gif" alt="" /> Air flow not being quite accurate won't change timing this much, but BARO will. <img src="/forums/images/graemlins/frown.gif" alt="" /> So, I'm back to square one. Literately. I'm going to have to start all over, remap and then build a new timing and fuel map. Sigh.
And all that sucks because it's late fall here in CO so the temps are way down. I've had the F/IC disconnected for a week and haven't had any problems with overheating even on the little drive I took Saturday to confirm MAF operation, but that doesn't mean anything. Until next summer when the temps go up I won't know if this means I've been chasing my tail for 8 months and I don't even need the F/IC or if it'll run all right without it as long as its only 50-60 degrees or lower out or what.
I currently can't detect any detonation even if I really lug it in 3rd at low RPM on steep inclines but like I said, it's been 40 degrees, so ....
Anyway, I'll keep plunking away. If the temps get up to 70 this weekend like they say, I'll take it up and see what happens on my test canyon trail and see if it overheats in 4WD or I can detect any detonation.
On the plus side, it runs like a top with the new MAF. Glass smooth and I seem to have gotten rid of the exhaust stink that wasn't normal that I've had for 3-4 years.
Edward
