New isc, repaired ecu still dies at idle

[trunks]

I have dsmlink and the isc reading is 116 with the ignition on. I watched it climb from the 90's on when the trouble started. If I pull the negative terminal on and off it will buzz. However, then I tried the ignition on/off test and it is not moving in and out at all.

I rechecked my ecu drivers and they are fine. It was pretty dark but I tested the plug and I believe pins 1 and 5 are powering. My wiring harness hasn't been hacked or anything either.

I've searched all day and am at a loss. Any thoughts are appreciated!

 

[tsi1991awd]

Check the ECU caps again. Sometimes the damage to the board is UNDER the caps and hard to see. I would replace the caps anyways.

Just because it dies at idle doesnt always mean it is the ISC or ECU. Take the plug off of the ISC and test the resistance between the coils on the ECU. Measure across 1-2, 2-3, 4-5, 5-6...should be 128-130. If they are below or above that by a long shot, your ISC is dead. Sometimes they may read 140 if they are the brand new brand new ones.

You may have a big boost leak....if you do, the car will also die, or at least try if it is big enough.

There are so many other things too man...you cant just assume it is the ISC or ECU. Could be a spark problem, could be a fuel problem...maybe your MAF sensor is dead or dying....hard to say without more info. Just saying "why is my car dying" wont get you anywhere.....need details.

 

[trunks]

The ISC is brand new from parts store. My AFR is dead on 14.7 as the car was professionally tuned last fall and not driven all winter. All boost leaks were fixed at that time as well.

I believe this to be the problem as dsmlink had been reading 100 on the ISC position at warm idle where as everything I've read says it should be around 30. Also, when I kick the a/c in it doesn't compensate for the load and really dies hard. After killing it starts up and idles fine.

I'll pull the board out tonight and look at it closer. I've only driven it twice this year for about 120 miles on the repaired ecu and from what I've read it usually fries it after continous driving on a bad ISC.

Thanks for the reply,
Aaron

Well, my ecu had some discoloration on the bottom so I switched it out with a spare. Car ran great for a while compensating for the a/c just fine. When I brought it home I let it idle for a while with the a/c on and it started to surge badly. When it finally died I fired it up again and the isc was reading 0 unless I reved it.

I had the alternator signal come on and saw just over 11 volts at the battery.

Could a bad alternator be blowing my drivers? Just like my first times out it ran good for a while and then starts stalling - after driving for like 30 minutes. The alternator seems to recover and then I get 12 to 13 volts so I don't know if this is related. I guess a new alternator is next.