| Running issue from yesterday....resolved? |
Subject: Running issue from yesterday....resolved? by Matatk on 2011/6/7 16:51:56 Well, I posted the other day that I drove my car to work and is was missing at WOT. Seemed like an ignition issue. Then I drove it yesterday to Rick's and it was running like crap again. OK at idle/low throttle, but stumbling, hesitating, and missing when you'd give it hard throttle. I pretty much narrowed it down in my mind to a few culprits: Ignition system (because of symptoms) Timing (thought dist might have slipped) ECM (since I had a comm error before when datalogging) Loose chip (I have zif adapter) MAF (intermittent code 33 over early spring when I was driving it in cold weather) The other day I checked the plug wires and they seemed fine. Last night I checked the timing and it seemed fine. Swapped the ECM this morning, made sure the chip was set in tightly. Took it out for a drive and at first it seemed to run well for a few blocks. Then it stopped running well and the symptoms were: Weak acceleration/general slugishness Flat spot in acceleration 3400-4000 rpm Backfiring when downshifting to accelerate around 2200 rpm I came home and swapped the MAF with a used one I have in the garage (borrowed from Woodstock - thanks Axel!). Took the car back out and it was totally different. The weak acceleration is gone, no more backfiring, ran totally different. It's still not where I think it should be, but I'm wondering if the tune is out of whack since I changed the MAF. There are documented problems with changing MAF sensors especially on modified cars. I'm gonna get another MAF soon so I can take Axel's out. Then I need to do some more datalogging. I need Mick to change a few parameters. But as for now, the MAF seems to have been the culprit. I don't normally throw parts at a problem, but since I already had them it only took a few minutes to swap out. I'm gonna have to check my plugs, too, I think they might be fouled up from it running wrong for a bit. Just thought I'd share in case anyone else runs across a similar issue. Matthew |
