possibly bad ISC? no idle surging...

[foxfan88]

I am still a dsm newb basically in the fast i dont know whats "normal" for these cars, as far as how they act.

My car on a stone cold start will start pretty good, and idle around 12-1300 rpm, and gradually go down to 750-800ish.

This is there isnt no initial jump when it first starts like i'd expect the car to do.
Also when rolling down the road, and if a press in the clutch, the RPM will fall right down the base idle, there is no sort of preposition going on to hold the idle up slightly while the car is rolling. Once again, i dont know if these cars are supposed to do this or not.

FWIW i have a 91 mustang, and upon and rev of the motor as the rpms fall, it will hold it self up slightly for a second or so before dropping down the normal idle and the ISC goes back to controlling the idle..

When my talon is warmed up and when i start it, just sort of burbles up the normal idle, no ISC rasing the idle slightly like i'd expect it to, my mustang will raise the idle slightly even on a warm start and it will drop pretty fast to the normal idle.

Also on the talon, turning the AC will bog the motor down real bad, down to 500 or so. Once the AC clutch disengages the engine will idle up to normal and then once it comes back on the idle bogs down again.

I can also unplug the ISC connector from the car and i noticed no changes in how the car started or anything. I guess that would give it away right there eh?

I have no surging idle issues at all, just the problems i posted above.

Should the ISC be holding the idle up when the car is moving and should there be a slightly higher idle even on warm starts for a short time??

 

[garrek11]

all that piece really is is a stopper for the throttle. mine was sticking at high idle when i pushed the gas pedal down it would stick at around 3000rpm and i messed with it for a little bit and found the right adjustment. do the same and see what happens and make sure your don't have a throttle body leak or a vaccume leak. oh and it doesnt make a diff if its pluged in or not.

 

[foxfan88]

What do you mean it doesnt make a difference if its plugged in or not. If the ISC motor is working like it should i should be able to tell a difference if its plugged in or not. I can run the car and pull over on the side of the road and unplug the connector and notice absoutlely no change.

Today i also checked the voltage at the connecter with a volt meter, the two center wires are gettign 12v with the key on.

As for th adjustment, are you referring to the BISS adjustment. ive done this as best as i can. I grounded the timing pin near the battery and also grouded the 3rd pin up on the diag port and set the base idle. A thing i did notice is I noticed no changes in the idle as i grounded the diag port pin for the ISC. If the idle was real far off (like it was initially) then i surely should have noticed some sort of change in the idle. When i made the first adjustment, i found the BISS turned all the way in, the car idles real low. If the ISC was functioning i would have guess it would be open more trying to get the idle up. If grounding the pin in the diag port sets the ISC to 50%, the car should have stalled or idles even lower if the bypassed air was cut down. In my instance i noticed no changes.

Pretty confident there are no vac leaks, but i can always check to make 100% sure.

 

[Guzman08]

my car slowly rises to 2k and stays there on N,.. where can i find this.. any pics f what to adjust?