Tuning the Timing Advance

[missouri_dsm]

if the throttle shaft seals are leaking it will definately make a big difference. And your seals are probably the original 15 year old seals so they are probably part of, or all of your problem.

 

[steve]

In the factory service manual, it says to take the ISC out and have a friend turn to ACC on and off with the key and make sure the ISC motor moves in and out. It tests fine when I do that, so does that mean the ECU is working properly? Or does that not mean anything?

It's a good sign but unless you have seen both a good ISC and a bad ISC rehome when you turn the ignition on it's hard to tell the difference between a smoothly stepping ISC and one missing steps because one of the drivers is bad.

I usually use the AC idle up and watch the ISC steps once the car comes up to temp to see if it's working.

Steve

 

[jonheslop]

I'm trying to think and elimate all my problems. I've narrowed it down to the ISC and some sort of gasket/seal leak. Other than that everything has been tested or solved. I hate to buy a new ISC is that's not the problem. And I hate to buy a new ECU if that's not the problem. I'm just going to wait for these shaft seals to come in so I can start small.

 

[Auto RS T]

Check Throttle linkage...is it too tight holding the butterfly partially open?/ Re-check FIAV block off/ Replace TB shaft seals, keep us posted

 

[jonheslop]

The linkage is fine, not too tight, and I am going to check the FIAV and rebuild the throttle body as soon as the parts come in.