odd Idle problem..

[JesseH]

Ok, I just put on the ported and polished intake manifold from Will on here and everything was going good until randomly today the Idle started jumping up and down, but yet while moving it runs perfectly fine.....Im really confused on what it could be, anyone have any ideas?

 

[CRE]

Have you checked the ISC?

EDIT: The next thing I'd check after that would be the vacuum lines, then AFM. D'oh, and let's not forget the TPS.

 

[ForcedTorque]

I'm going to show a little ignorance here............There is a little disc underneath the ISC. I have been told without it, the car will act as you describe. I don't have a clue what it is called.

 

[jdub]

It's a check valve...if it's clogged up with carbon, it will cause all kind of mischief with your idle

 

[JesseH]

I'm going to show a little ignorance here............There is a little disc underneath the ISC. I have been told without it, the car will act as you describe. I don't have a clue what it is called.

It's a check valve...if it's clogged up with carbon, it will cause all kind of mischief with your idle

actually thats one thing I was going to ask about, your talking about the one with the vaccum line right? it has never been connected on mine due to I have no spot around for it to connect to.

 

[jdub]

No...the check valve looks like a little mag wheel. It is under where the ISCV bolts to the manifold.

Are you talking about this?
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=EC&Page=8

If so, The dashpot VTV is not suppose to be connected to anything on the end opposite the diaphragm...all there is ia a little filter on the end.

 

[JesseH]

No...the check valve looks like a little mag wheel. It is under where the ISCV bolts to the manifold.

Are you talking about this?
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=EC&Page=8

If so, The dashpot VTV is not suppose to be connected to anything on the end opposite the diaphragm...all there is ia a little filter on the end.

oh ok, would you happen to have a pic or the TSRM page whith the check valve? thanks

 

[jdub]

I just noticed you have a NA motor...you don't have the check valve under the ISCV

Your ISCV could still be bad...here's the test:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=106

You could also have carbon build-up in the valve seat too.

 

[JesseH]

I just noticed you have a NA motor...you don't have the check valve under the ISCV

You ISCV could still be bad...here's the test:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=106

You could also have carbon build-up in the valve seat too.

actually since I just put the manifold on, I cleaned the sh*t out of everything that had to do with the manifold, I also put new valve cover gaskets on while I was at it...so all of it was clean when I put it back on, but just a little bit ago for the hell of it I took the ISC back off sprayed it down with carb cleaner and hit the electrical connections with CRC contact cleaner....I just went out a a test drive a few min ago and it seems like the problems is gone...

 

[jdub]

To clean the ISCV properly, you have to remove the stepper motor...3 philips head screws...from the aluminum base. You'll be surprised how much carbon is inside
Same idea though, use carb cleaner to remove the carbon.

 

[JesseH]

To clean the ISCV properly, you have to remove the stepper motor...3 philips head screws...from the aluminum base. You'll be surprised how much carbon is inside
Same idea though, use carb cleaner to remove the carbon.

ok, thanks, ill do that tomorrow:icon_bigg

 

[jdub]

NP...I've taken dozens of these apart...the motors only go on one way, so it's easy. There is a hard rubber washer around the base where the stepper motor fits. Be careful you don't tear it.

 

[JesseH]

one more thing, are you talkin about the brass screws thay fully take the motor apart? or the three screws that are connected to the housing?

 

[jdub]

Here's a side shot...you can see one of the screws holding the motor down to the housing. It's sticking through the aluminum a bit.

 

[JesseH]

Here's a side shot...you can see one of the screws holding the motor down to the housing. It's sticking through the aluminum a bit.

oh, well in that case I've already cleaned it out lol

 

[jdub]

Before or after your problem started?

 

[JesseH]

Before or after your problem started?

after, so from what I can see i believe that was my problem....Ill know for sure when I drive it for 30 min or so tomorrow.

 

[JesseH]

ok, its still happening,but not as bad now....does anyone have any other ideas of what I could check?

 

[jdub]

Are all your vac lines in good shape and connected the where they are suppose to be?

You mentioned one that was not hooked up...which one?

Have you removed any "unnecessary" parts to cleaning up the engine bay?

 

[jetjock]

Pssst...here's two things that have never been mentioned in the history of this forum: Codes? IDL contact closed?