1G New ISC Procedure

[Paturk]

I tried hunting down the procedure on vfaq, but it seems like a lot of pages are no longer available. I have been having some bouncy idle issues after maintenance items. I installed new plugs and wires. FIAV block off plate, new biss and isc. Is there a procedure to relearn the idle or process new ISC/IAC? Heads up the car idled fine and Thames sat for a year, and I am did a bunch of maintenance.

 

[92AWDHX40]

No just install the isc, doesn't need to relearn anything

 

[Paturk]

No just install the isc, doesn't need to relearn anything

I guess it is back to the drawing board then with my idle issue. Thank you. From what I can tell it can be a multitude of things, so I guess I’ll make sure again no vacuum and boost leaks, and check out the ECU.

 

[92AWDHX40]

Yep could be several things still

 

[Paturk]

Yep could be several things still

I haven’t even driven it more than about 5 minutes since putting it back together. Do you think that would help at all, or should I figure out my issue first so I don’t cause any damage?

 

[enriquez2000]

Not to sound like a broken record but do a boost leak test.

I just did one and found a less than 6 month old injector seal hissing like a banshee.

So many places air can enter

 

[Paturk]

Not to sound like a broken record but do a boost leak test.

I just did one and found a less than 6 month old injector seal hissing like a banshee.

So many places air can enter

Yeah I will be doing one this morning. Thanks.

 

[Paturk]

Not to sound like a broken record but do a boost leak test.

I just did one and found a less than 6 month old injector seal hissing like a banshee.

So many places air can enter

Well turns out the manual boost controller that was already on the car was leaking quite a bit. I took that off and car stopped bouncing in idle. Also turns out the aftermarket exhaust manifold I got from a friend is buns and leaks as well. Thanks a ton

 

[Mech Addict]

I would not have guessed that either of those could be the issue. Shouldn’t be making any boost at idle. Not sure how a leak in the exhaust would factor in to poor idle.
Glad it worked out, though, for whatever the cause.

 

[enriquez2000]

Well turns out the manual boost controller that was already on the car was leaking quite a bit. I took that off and car stopped bouncing in idle. Also turns out the aftermarket exhaust manifold I got from a friend is buns and leaks as well. Thanks a ton

At least you got your answers!

 

[Paturk]

I would not have guessed that either of those could be the issue. Shouldn’t be making any boost at idle. Not sure how a leak in the exhaust would factor in to poor idle.
Glad it worked out, though, for whatever the cause.

Yeah I believe because it was right where vacuum enters the boost controller it was one of the small ports on it that was leaking.

 

[enriquez2000]

Yeah I believe because it was right where vacuum enters the boost controller it was one of the small ports on it that was leaking.

Bingo! Boost leaks are 99 percent of the time also vacuum leaks
..

Yoir manifold wont cause that idle surge though so good thing you got it adressed before you build power.

Get those fixed and test again until there are no more.

 

[motomattx]

Some manual boost controllers by nature of how they work leak boost and vacuum to some degree.