86 Vacum / low idle issues ASAP

[mx3twinturbo]

I have a car here, its an 86 I have never really delt with the 84-86's

the car runs good when warm, then idles down, and wants to die, the car came into my shop not running (had bad valves)

now has new valves and such,

also had to add a maf once it was added it runs great except with the issue explained above,

 

Good-Fuel Pressure, Timing,spark, no vac/boost leaks

good tps,

 

Bad-

Unsure of the ISC's ability to adjust all the way,

 

The solenoid on the firewall next to the baro sensor (can i remove this)

and just run the baro sensor?

I have looked at all the vac references on the starquest forums, and all the service manuals,

and ran it in a few variations,

 

 

I have alot of experience with the 87-89 cars, and this is stumping me, (and my customer want's his car back, lol)

Please any help will do me good!

 

Thanks,

Jesse

[newquest86]

did you do the tps isc reset also the 86 does not have the base idle screw that 87-89 have but it does have a little screw on the firewall side of the throttle body linkage you have to adjust once you are doing the reset sounds like this might be your problem i could email you the reset procedure if you need it just pm me your email if you need it

[Indiana]

The ignitor controls that solenoid valve you need it there but its part of pulling boost and timing for knock but its not part of idle. The idle still sets up the same way for the TPS and tip switch and uses the CTS. That fixed hard stop screw back it off and make sure the cable is slack and the ISC screw put it in the middle of its range of adjustment and assuming the injectors aren't spraying too much from needing cleaning it should idle. After you get it to idle near where you want it, tweak that with the ISC screw as this isn't using a motor position sensor like you are used to so this is where you set the idle up but you need to re verify afterward that the TPS is still below .5v. Those injectors are sensitive to being dirty as both are pretty large and both are firing back and forth. Its not like just one small injector on the 87-89 and if its dirty it not that big a deal. 86s can foul out idling if those are dirty. Using an OEM PCV valve? If that is stuck or not OEM or the hose cracked idle may be higher because its sucking in more air.

 

 

 

http://www.b2600turbo.com/images/boostpressuresolenoid.jpg

http://www.b2600turbo.com/images/highaltitudesolenoid.jpg

http://www.b2600turbo.com/images/86vachoses01.jpg

http://www.b2600turbo.com/images/86vachoses02.jpg

[Shelby]

your coment about low idle vacum,,that sounds like the cam is 1 tooth off at the crank