Car suddenly won't idle/run
Thread Starter
Joined: Jun 2014
Posts: 1,241
Likes: 47
From: Noblesville, IN
Car suddenly won't idle/run So I've been working on tuning my VE Table. Took it out last night and drove around for a bit, mostly trying to dial in the normal driving cells. Got home, made edits to the table, it got a little late so i decided to pick up where I left off the next day.
Got up, flashed the new tune to the car, went to start and it revved to 1600 and immediately died. Tried a couple more times, same thing, doesn't care at all whether or not I give it throttle.
Said okay, I must've made a mistake, so I went and flashed the previous tune (which I had just driven with the day prior). Went to start and instead it would hunt around between 300-800 rpm for a bit before dying. Giving it throttle only exacerbated the issue.
Did I screw up somewhere? Here's a log of it starting and dying, and here's a copy of the "Good" tune that I drove with last night.
Got up, flashed the new tune to the car, went to start and it revved to 1600 and immediately died. Tried a couple more times, same thing, doesn't care at all whether or not I give it throttle.
Said okay, I must've made a mistake, so I went and flashed the previous tune (which I had just driven with the day prior). Went to start and instead it would hunt around between 300-800 rpm for a bit before dying. Giving it throttle only exacerbated the issue.
Did I screw up somewhere? Here's a log of it starting and dying, and here's a copy of the "Good" tune that I drove with last night.
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
The VE is a bit on the bumpy side, looking at your IAC vs Effective area table, it appears to be shifted right pretty far, which will limit it's range, or it's perceived range as far as the PCM is concerned, making it more touchy.
From the log, it's difficult to nail down a root cause, but I would start by bumping idle up a little in the scanner, and trying to get a solid log to go off of. Also, fixing the IAC table might do wonders. Instead of shifting the table, trying using the dynamic air correction maths formula. Also, don't change the max limit (310 typically) but instead change the slope. That's more realistic as to what is happening with changes in throttle bodies or cam (aka vacuum) changes.
Hopefully that helps. Tuning idle is a pain... no doubt.
From the log, it's difficult to nail down a root cause, but I would start by bumping idle up a little in the scanner, and trying to get a solid log to go off of. Also, fixing the IAC table might do wonders. Instead of shifting the table, trying using the dynamic air correction maths formula. Also, don't change the max limit (310 typically) but instead change the slope. That's more realistic as to what is happening with changes in throttle bodies or cam (aka vacuum) changes.
Hopefully that helps. Tuning idle is a pain... no doubt.
Thread Starter
Joined: Jun 2014
Posts: 1,241
Likes: 47
From: Noblesville, IN
Yeah the ve is what I've been trying to tune. I have a good working tune that's maf only, but I was trying to get the whole thing complete.
Since my maf tune works well, should I use that to get my IAC tables correct, then go back to the ve table?
Since my maf tune works well, should I use that to get my IAC tables correct, then go back to the ve table?
