ISC has gone crazy

[Xit40]

Ok well my ISC has gone crazy. It bounces up and down all over the place. It was fine a week ago or so. Held firm at about 67. I know that is a little higher than what it is supposed to be, but that is why I went to work on it today. Now when I log with dsmlink the thing bounces all over. What could have caused this? I did a boost leak test and everything was fine. Could it be my FIAV? Logs are attched before it went crazy and after. Please help. I was hoping to get this thing tuned today.

 

[scottsee]

scottjsee - DSMlink Idle Adjustments scroll down to Adjusting Base Idle

 

[Xit40]

I understand how to adjust the idle and set up all the parameters, but it's impossible to do with a crazy ISC. I'm just looking for reasons as to why this would happen. From what i understand if it's dead it usually just doesn't move, but feel free to jump in and help me out here.

 

[pneumo]

There's no way to log the actual ISC step, the logger just shows which step the ecu is trying to hit.
If the ISC changes over a wide range with no change in idle rpm, chances are you have a bad ISC.

 

[scottsee]

Simple a quick answer is to swap out the TPS with a known good one, adjust the TPS to allow RawThrotPos @ 32 and see if that fixes your issue..

 

[94cyclone]

the ISC and FIAV systems are not necessary, they cause so many issues. I just blocked them off.

 

[boostnhard]

the ISC and FIAV systems are not necessary, they cause so many issues. I just blocked them off.

Wow why would you say something like that? well oviously you dont have A/C

 

[94cyclone]

A/C? I live in the north, we don't need no stinking A/C!

 

[boostnhard]

A/C? I live in the north, we don't need no stinking A/C!

Well just because you, in your car, in your north dont need it, it doesn't mean its not necesary.
Other people who dont live where you live, may read it and be mislead by you
its not fair for people who are new to dsms.

So next time think about what you're going to type before you do it, remember this is a comunity to help each other out.

 

[Xit40]

Ok so anyways I fixed the problem. Dave at DSMlink suggested I remove the captured values and then reinput them in. Sometimes he said the computer gets confussed as to what exactly it is logging. He noticed the ISC was outside the values it could step to. So after a little work I got it to work correctly. My ISC now steps to 30 as it should at idle. Thanx for the help. Please mark resolved.

 

[doggo]

Wouldn't disconnecting the battery allowing the ECU to reset itself, do the same thing regardless of running ECU with or without DSMLINK?