Idle and deceleration issue

[hisandherturbo]

K, here goes nothing. I have been living with this for too long now. I try and get my idle right and think I do. But here's what happens; If it's not idleing at 1500 it's surging between 1000-1500. Here's the kickers. Base timing is 5* BTDC, Biss doesn't help, NO LEAKS! I SAY AGAIN, NO LEAKS!, ISC Ohms out "right". I thought it was a bad FIAV so I installed a "BLOCK OFF PLATE" And that fixed everything except the dying on deceleration (like coming up to a red light). Well, I thought if I installed a "BYPASS PLATE" (STM: JMF FIAV BYPASS PLATE | 90-94 DSM) I could get my idle back and maybe help my deceleration issue. Welp, NOPE!!! Not only did it not help my deceleration issue, the high idle and surge came back. So it appears my ISC seems bad, HOWEVER it tests fine. Link shows TPS Volts at idle at .64 HOWEVER ISC position is like 100 (I know that isn't right, but it doesn't adjust and stay lower). Throttle position is either 0 or 1%. Also link won't do anything when I try and change the TGT Idle.
When I am NOT doing the surge thing both Idle SW and Loop mode is 1 then switches to 0 after applying gas (first SW, then Loop).
All trims are withing 2% of Zero (STFT, LTFTLo, CombinedFT) when it's not acting up.
K, what is wrong? I want to know what happened? I don't want to hear, put a block off plate back on and live with restarting your car at every red light. I don't want to click this, click that, and band-aide it, I want to know what happened and why then fix it!!!

TY
JOE

 

[3kgt2nv]

Have you checked your maf, the ecu is trying to adjust for the false readings if the maf is bad.

 

[hisandherturbo]

Yes, I have checked my MAF and a bad MAF wouldn't go "good" because I installed a block-off plate would it?

 

[3kgt2nv]

Did not see it listed in your check list so I mentioned it. The block off plate might have helped since the FIAV wouldn't be adding more air to the engine the ecu couldn't compensate for

 

[hisandherturbo]

Did not see it listed in your check list so I mentioned it. The block off plate might have helped since the FIAV wouldn't be adding more air to the engine the ecu couldn't compensate for

A bypass plate (which is what's on it now) also blocks the FIAV, just doesn't block the ISC.

 

[3kgt2nv]

you have anyone you could borrow a isc from just to see if it is shot even though its testing fine?

 

[hisandherturbo]

you have anyone you could borrow a isc from just to see if it is shot even though its testing fine?

That's what I want to see if I can try tomorrow (buy a used one from a pull and pay). Just because that is what it soooooooooooooo looks like, but I wanted to research, pick brains until then.

 

[3kgt2nv]

my isc when it went bad was surging at idle but on decel it wasnt stalling but both are signs of a bad isc.

 

[hisandherturbo]

my isc when it went bad was surging at idle but on decel it wasnt stalling but both are signs of a bad isc.

Did you test yours? Did it pass/fail? Or did you just say, it's bad and get a new one?

 

[3kgt2nv]

i just got a new one. i keep all my parts so i could go back and retest it if i wanted to. If i was you i would buy a new one to eliminate the possibility of getting a bad one from the pick and pull

 

[hisandherturbo]

i just got a new one. i keep all my parts so i could go back and retest it if i wanted to. If i was you i would buy a new one to eliminate the possibility of getting a bad one from the pick and pull

To test, set multimeter on "ohm" and while you are looking at the ISC you will have 3 across and 2 down...........

1 2 3
4 5 6

Test 1&2 and 2&3 each should be about 30 (black ones are higher) then do the same with 4&5 and 5&6

And NO WAY would I buy a new one, 2 reasons, I am sure waaaaaaaaaaaaaay to expensive, can't return electronics, and I am not convinced it's bad.

 

[haywire96tsi]

I am having same problem !!!! I tryed different tb, different isc, different tps. Same problem dont know what to do?

 

[gusu]

A bad ecu can do this too. If whoever had it before you waited to insta a new ISC the ecu could have started to go bad from it too. I'd check that, mine was leaking once with out the fish smell.

 

[XiKeiyaZI]

Just tossing this out there, but is the BISS adjusted correctly? I've recently learned that you can actually have it idling correctly but the ISC will not be at a 'good' position and as it attempts to match the flow to lower/increase idle that it maxes out and cannot open the plate enough to keep the car idling. I was having this same issue until I adjusted my TB.

Turn the BISS out a bit and wait about 30 seconds, even if the idle is at 3000. If the solenoid is functioning then it should adjust and lower the idle.

 

[haywire96tsi]

I was having a dying out issues on decel and red lights. Found out if you running ecmlink v3, there's a fix it's called idle air clamping. You can read about it on there ecmlink wiki I hope it works for you.

 

[hisandherturbo]

I was having a dying out issues on decel and red lights. Found out if you running ecmlink v3, there's a fix it's called idle air clamping. You can read about it on there ecmlink wiki I hope it works for you.

Tried that, it didn't change anything for me, and according to Thomas, that isn't "exactly" what it's for... but it sometimes "helps', but ty for that info.