ECMlink 1g idle surge after warm

[94_TSi]

I have been through all the procedures for idle surge and still cant make heads or tails of this one. As you can see in the log it is basically temperature dependent.I have also tested the coolant temp sensRr and its good. Abuddy who is helping with the tuning process is also a member here and will most likely chime in, here it is and thanks.

 

[concept4g63]

Couldn't read the log, but, for that surge make sure you have no vacuum leaks anywhere, and also make sure timing is correct, do the basic tests and see how it goes

 

[94_TSi]

Everything is dead on.

 

[big_d]

Just a little background... The car is a built 2.0 on speed density, magnus smim, rebuilt throttle body with the FIAV blocked. Running E85 with FIC, BM 1450's. We tested two ISCs, and both yielded the same results. No matter the biss position, the ISCposition would never move from 0. Sometime the car will calm down and idle correctly and operate normally in closed loop. As you can see in the log the car was idling great until the throttle was blipped...It seems we've tried everything in the book. Idle stop switch is adjusted perfectly. Base timing is set. Boost leak test was perfect.

Any help is appreciated. We know the coolant temps got a little high (fans aren't wired up yet)... Oh and Matt, update your profile so people have the full rundown

If anyone sees anything out of whack in the ECUconfig settings, speak up. I've never helped anyone tune SD on V3, but I think we have everything covered.

 

[94_TSi]

Mod list is updated.

 

[big_d]

Alright... little update from last night. The last thing to test as far as idle is concerned was correctly adjusting the BISS... Started the car, warmed up to operating temp, grounded the connectors. At this time the ISCposition is at 9 (which should be fine... I believe 9 is the default value). After setting the idle (right around 900 b/c of the cam), we shut the car off and the grounds were disconnected. After restarting the car, the car idled fine. ISC moved around, but always seemed to default to one of the extrema (0 or 120). After fixing a couple other issues, I tried the BISS adjustment again (began surging after some revving and such) but the ISC would not move from 0.... I'm not sure why, but it almost seems like we need to completely lose power and reset the long term isc position back to its default value.

Basically here is what we need to verify:
- The ecm stores a long term ISC value (Learned idle adjust) which I haven't been capturing. Since we were having trouble with the narrowband simulation to begin with, the car was in open loop for quite some time. We need to reset the ecm, and make sure this value defaults to 144 before we do a BISS adjustment.
- Testing of the ISC was fine ~31ohms for all. Also need to verify isc movement using a 6V battery.


*** We'll keep you all posted. Any suggestions please post.

 

[911gdsmboostin]

Alright... little update from last night. The last thing to test as far as idle is concerned was correctly adjusting the BISS... Started the car, warmed up to operating temp, grounded the connectors. At this time the ISCposition is at 9 (which should be fine... I believe 9 is the default value). After setting the idle (right around 900 b/c of the cam), we shut the car off and the grounds were disconnected. After restarting the car, the car idled fine. ISC moved around, but always seemed to default to one of the extrema (0 or 120). After fixing a couple other issues, I tried the BISS adjustment again (began surging after some revving and such) but the ISC would not move from 0.... I'm not sure why, but it almost seems like we need to completely lose power and reset the long term isc position back to its default value.

Basically here is what we need to verify:
- The ecm stores a long term ISC value (Learned idle adjust) which I haven't been capturing. Since we were having trouble with the narrowband simulation to begin with, the car was in open loop for quite some time. We need to reset the ecm, and make sure this value defaults to 144 before we do a BISS adjustment.
- Testing of the ISC was fine ~31ohms for all. Also need to verify isc movement using a 6V battery.


*** We'll keep you all posted. Any suggestions please post.

Hate being the guy commenting on a extreamly old thread.. but did you ever resolve this? I am having the same issue. And have no idea what to try now. Ive covered all bases as you did. Im at a loss here.