cheekychimp
Well-known member
^^^ Now you tell me! /ubbthreads/images/graemlins/banghead.gif
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Let's talk FIAV and ISC block off plates!
- Thread startercheekychimp
- Start date
cheekychimp
Well-known member
Right, update!
A while ago I picked up an EVO III intake manifold with a really good condition throttle body on it. I pulled the throttle body apart and separated the ISC and FIAV assembly from it. I then installed that bottom half onto the S90 billet throttle body together with a brand new ISC from DSMISC.com and the JNZ FIAV block off plate I had ordered to fix my idling issues.
But no dice! The car started but idled at 2000 rpm no matter how we adjusted it. The car had been idling better than that previously so despite the fact that I suspected the old ISC to be going bad, we put it back in anyway. Instantly the car starts idling as smooth as butter ... /ubbthreads/images/graemlins/dunno.gif
We put both ISCs side by side and the one from DSMISC.com is a good 1/8 of an inch shorter than the stock JDM one hence the fact that it was leaking air and not sealing properly leading to the high idle. I thought initially that maybe the EVO III throttle body itself was different but I realized it couldn't be that since the stock JDM ISC that we put back in was from a JDM VR4 throttle body. I suppose I should throw the EVO III ISC in just to confirm if it works and if it does keep it as a spare since these 'brand new' ISCs I have aren't much use as they stand.
So anyone heard of this issue before? DSMISC.com says the ISCs should work for VR4s, so I can only guess the USDM VR4 throttle body is different or you guys using the DSMISC.com ISCs are also using the bottom half of a DSM throttle body.
At least I have a decent idle now. Only issue is starting the car cold with the A/C cranked on full (17 degrees). Without A/C or on a moderate setting it starts straight off the bat.
But it STILL hunts badly and stalls on hot starts if switched off for 15 minutes or less. I cannot for the life of me figure out why. I heard that there is some sort of code in the ECU for hot starts. What does that incorporate and could it be causing any issues?
Guess I also need to work out how to test the resistance in the coils on the old ISC to see if it is really going bad and then maybe try to find a decent DSM lower throttle body section so I can use these damn new ISCs I bought.
A while ago I picked up an EVO III intake manifold with a really good condition throttle body on it. I pulled the throttle body apart and separated the ISC and FIAV assembly from it. I then installed that bottom half onto the S90 billet throttle body together with a brand new ISC from DSMISC.com and the JNZ FIAV block off plate I had ordered to fix my idling issues.
But no dice! The car started but idled at 2000 rpm no matter how we adjusted it. The car had been idling better than that previously so despite the fact that I suspected the old ISC to be going bad, we put it back in anyway. Instantly the car starts idling as smooth as butter ... /ubbthreads/images/graemlins/dunno.gif
We put both ISCs side by side and the one from DSMISC.com is a good 1/8 of an inch shorter than the stock JDM one hence the fact that it was leaking air and not sealing properly leading to the high idle. I thought initially that maybe the EVO III throttle body itself was different but I realized it couldn't be that since the stock JDM ISC that we put back in was from a JDM VR4 throttle body. I suppose I should throw the EVO III ISC in just to confirm if it works and if it does keep it as a spare since these 'brand new' ISCs I have aren't much use as they stand.
So anyone heard of this issue before? DSMISC.com says the ISCs should work for VR4s, so I can only guess the USDM VR4 throttle body is different or you guys using the DSMISC.com ISCs are also using the bottom half of a DSM throttle body.
At least I have a decent idle now. Only issue is starting the car cold with the A/C cranked on full (17 degrees). Without A/C or on a moderate setting it starts straight off the bat.
But it STILL hunts badly and stalls on hot starts if switched off for 15 minutes or less. I cannot for the life of me figure out why. I heard that there is some sort of code in the ECU for hot starts. What does that incorporate and could it be causing any issues?
Guess I also need to work out how to test the resistance in the coils on the old ISC to see if it is really going bad and then maybe try to find a decent DSM lower throttle body section so I can use these damn new ISCs I bought.
Last edited:
chrisfullwood
Well-known member
ill look tonight, i just got a replacement throttle body (fully rebuilt) and i got a new ISC from DSMISC, so when i get back to my house ill do a comparison of the brown ISC i have, and the new black one i just got, and let you know what i find.
boostedinaz
Well-known member
Make sure the TB is grounded and that the idle switch is set up correctlty or ignored in DSMlink (not sure what tuning device yo are running).
If not my guess if that the block off plate my be letting in air. I always used JB weld abd make sure if was flusch so that the stock gasket would make the seal corectly. With a plate sandwiched in only one side has a nice tight seal.
Just my .02
If not my guess if that the block off plate my be letting in air. I always used JB weld abd make sure if was flusch so that the stock gasket would make the seal corectly. With a plate sandwiched in only one side has a nice tight seal.
Just my .02
cheekychimp
Well-known member
Quoting chrisfullwood:
ill look tonight, i just got a replacement throttle body (fully rebuilt) and i got a new ISC from DSMISC, so when i get back to my house ill do a comparison of the brown ISC i have, and the new black one i just got, and let you know what i find.
I'd appreciate that, thank you!
ill look tonight, i just got a replacement throttle body (fully rebuilt) and i got a new ISC from DSMISC, so when i get back to my house ill do a comparison of the brown ISC i have, and the new black one i just got, and let you know what i find.
I'd appreciate that, thank you!
cheekychimp
Well-known member
Quoting boostedinaz:
Make sure the TB is grounded and that the idle switch is set up correctlty or ignored in DSMlink (not sure what tuning device yo are running).
If not my guess if that the block off plate my be letting in air. I always used JB weld abd make sure if was flusch so that the stock gasket would make the seal corectly. With a plate sandwiched in only one side has a nice tight seal.
Just my .02
Yeah some valid points here. First I'm not sure if the S90 has provision for the idle switch, I did see a wire floating about at the back of the TB after Ken installed it. That could well be an issue. Other than installing DSMLink/ECMLink and choosing to ignore that input is there anything I could do about that situation? The grounding of the TB could also be an issue but that's an easier fix.
Finally I don't discount the possibility of air leaking past that plate. I don't even think we put any RTV on it. But if it was leaking air wouldn't it have issues on a cold start as well? I can see that if the leak was small the ISC might compensate for it I just don't understand why on a hot start it can't compensate and the idle hunts so badly it eventually stalls /ubbthreads/images/graemlins/dunno.gif If it is leaking air, I'd actually be happy because either way that's another easy fix, we can either just do the JB weld method or make sure the plate seals properly.
Make sure the TB is grounded and that the idle switch is set up correctlty or ignored in DSMlink (not sure what tuning device yo are running).
If not my guess if that the block off plate my be letting in air. I always used JB weld abd make sure if was flusch so that the stock gasket would make the seal corectly. With a plate sandwiched in only one side has a nice tight seal.
Just my .02
Yeah some valid points here. First I'm not sure if the S90 has provision for the idle switch, I did see a wire floating about at the back of the TB after Ken installed it. That could well be an issue. Other than installing DSMLink/ECMLink and choosing to ignore that input is there anything I could do about that situation? The grounding of the TB could also be an issue but that's an easier fix.
Finally I don't discount the possibility of air leaking past that plate. I don't even think we put any RTV on it. But if it was leaking air wouldn't it have issues on a cold start as well? I can see that if the leak was small the ISC might compensate for it I just don't understand why on a hot start it can't compensate and the idle hunts so badly it eventually stalls /ubbthreads/images/graemlins/dunno.gif If it is leaking air, I'd actually be happy because either way that's another easy fix, we can either just do the JB weld method or make sure the plate seals properly.
chrisfullwood
Well-known member
Side by Side, they look pretty much the same, although the new one looks just a tiny bit shorter.
New one.
Old one, which after 5 or 6 different attempts at measuring, always seemed to be 1/16" longer than the new one. not at the little brown noise sticking out, but the black piece, that the brown part is connected into (hard to imagine, and explain). if you take the two, and lay one on top of the other, the little nose(brown piece) is the same length, but the other piece (the black part that is connected to the brown piece) is longer on the older ISC.
ok, so that was the crappiest description ive ever given, but i hope it makes the point of what i noticed on my ISC's.
i will give the disclaimer, that when i looked at mine, i noticed 2 things, one, i could turn it by hand about 1/4 turn, so lots of play, compared to the new black one. and 2, there was no o-ring in the ISC slot, which would explain the crappy idle i had. I dont know if the size difference is due to wear, or damage.
New one.
Old one, which after 5 or 6 different attempts at measuring, always seemed to be 1/16" longer than the new one. not at the little brown noise sticking out, but the black piece, that the brown part is connected into (hard to imagine, and explain). if you take the two, and lay one on top of the other, the little nose(brown piece) is the same length, but the other piece (the black part that is connected to the brown piece) is longer on the older ISC.
ok, so that was the crappiest description ive ever given, but i hope it makes the point of what i noticed on my ISC's.
i will give the disclaimer, that when i looked at mine, i noticed 2 things, one, i could turn it by hand about 1/4 turn, so lots of play, compared to the new black one. and 2, there was no o-ring in the ISC slot, which would explain the crappy idle i had. I dont know if the size difference is due to wear, or damage.
cheekychimp
Well-known member
Chris,
Thanks for taking the time to do that. I did read your post and was working through a few things when I had to rush back to the UK. I'm back in Hong Kong now and I have just been looking at my ISCs. It looks to me as though it is the nose that is a different length on the ISCs I have but the O-rings are completely different, I wonder f that is where air was getting through rather than at the nose which is supposed to extend to reduce airflow right /ubbthreads/images/graemlins/dunno.gif
Still looks like I either need to buy a new JDM ISC or find a US throttle body so I can use these brand new USDM ISCs in order to eliminate an old worn ISC as the issue.
Thanks for taking the time to do that. I did read your post and was working through a few things when I had to rush back to the UK. I'm back in Hong Kong now and I have just been looking at my ISCs. It looks to me as though it is the nose that is a different length on the ISCs I have but the O-rings are completely different, I wonder f that is where air was getting through rather than at the nose which is supposed to extend to reduce airflow right /ubbthreads/images/graemlins/dunno.gif
Still looks like I either need to buy a new JDM ISC or find a US throttle body so I can use these brand new USDM ISCs in order to eliminate an old worn ISC as the issue.
chrisfullwood
Well-known member
Your welcome, i noticed a slight difference, i actually got a new throttle body as well, and now i have 2 orings. I found out afterwards, that mine actually had no o-ring. lol
anyway, good luck!!
anyway, good luck!!
spooling92vr4
Well-known member
Try logging everything to see if that idle switch is getting contact everytime, maybe the throttle plate is sticking and the switch isn't engaging every time which makes the car idle down.. there is a new Zealand guy on here running that s90 also maybe see if he's got any issues with it?
GSX_TC
Well-known member
where did you get your rebuilt Throttle body from and where did you get the new ISC?
cheekychimp
Well-known member
GSX_TC
Well-known member
Thank u thank u
