Idles at 700 RPM's and stalls at stops.

[badabing33a]

ok i know this is a common problem, but all the threads i read are things like "low idle after swap" and stuff. my car (the Talon) ran fine 2 days ago. yesterday, it started idling really low. around 6-700 rpms. everytime i stop, it stalls. all i did to my car was put oil in it and used an air hose to spray all the dirt and other stuff in the engine bay. and i fixed a little dent. is my ISC stuck or not working properly? when i finsihed my car, i had to get a jump from a friend because it sat for a while. is it my battery? alternater? i guess it could be alot of things. thanks.

 

[RayBan GST]

try to adjust the ISC screw and see what happens plus check the BOV pipes that goes to the intake if it has a small hole it could create idling problem


good luck

 

[swapped92talon]

Badabing33a's car is N/T. So it is impossible to check any BOV or intercooler pipes. Try adjusting the BISS screw first. If that doesn't help try gettting a ISC that you can just try that you know is good before you go buying a new one and it possibly not helping. Good luck.

 

[nkosi]

Hey man to adjust idle u first ground the timing plug under the hood near the battery ...then unplug the ISC then u adjust the biss screw... u can turn the idle up a bit and before u re-attach the ISC and disconnct the ground turn the engine off and this will set ## idle ...good luck.

 

[steve]

Check the resistance of the coils on the ISC. The original metal version should read about 30 ohms on each winding and the newer black plastic about 40 ohms. If any of the coils are shorted or measure below 20 ohms you'll need the ECU checked for blown drivers. If the coils aren't in spec you'll need to replace the ISC. If you have a datalogger the ISC steps at idle when warmed up should be around 10 to 30 steps. It's important that it's not 0 or above 100, both would indicated that the ISC isn't able to correctly control the idle speed.

Check to make sure that the IPS is working. It should ground the signal from the ECU when the throttle is closed. So with the green wire attached to the IPS and the ignition on you should measure about 0 volts at the connector when the throttle is closed and more than 4 volts when you open the throttle slightly.

If the ISC and IPS check out you can try setting the base idle speed by grounding the timing check terminal under the hood and adjusting the BISS (Idle screw on the throttle) to get the engine to sit at 750 RPM. If the BISS seems to move on it's own you should take it out and replace the o-ring that seals it to the throttle body.

 

[badabing33a]

do i keep the car on while i ground the timing plug? and adjust the screw and everything turn it off? or keep it off?

 

[jrohner]

Just turn the idle speed up a little by adjusting the base idle screw out a little. I wouldn't even mess with the ISC because it seems like they never do work. If everything else is right, you will have a good idle without a working ISC. The only thing is that it will go down a little when you turn your headlights on or your A/C -- no big deal IMO.

 

[steve]

Since the ISC can damage your ECU I prefer to diagnose the problems rather than hack my way around them. The car is so much nicer to drive when things actually work well.

There are actually two different pins to ground for adjusting the BISS, the check timing connector under the hood and the mode pin on the DLC by the drivers footwell fuse box. It's easier to to them when the car is off and then start the car but you can also do it while it's running.

1G BISS Adjustment
DmTaLoN's Idle Speed Control Test/Fix Page!
DSMISC Automotive (New ISC Supplier)

 

[swapped92talon]

Yes have the car running when you connect the timing plug to the ground. This will change the timing of your car to it's base timing when it is hooked up (This is also how you set base igntion timing). Set your idle to specification like this, then when you unplug the ground your car will go back to it's normal ignition timing and should idle normally. If you personally work on your car alot a good book to get for it is the Chilton that has just the 90-94 DSMs in it. Good luck

 

[badabing33a]

ok i went out and checked when it idled low and how. if i have the lights, heater, etc. off, it doesnt do it so bad. as soon as i turn the headlights on, it about stalls. also, since it idles so low, the engine is knocking all the time like an engine does right before it stalls. if i hold the throttle open a little bit from under the hood, probably around 1300 rpm, the knocking goes away. so its not perminant, just idleing in nuetral or with the clutch in. i dont think it will stall when i have lights and everything off though. last night i was driving it at night so i obviously had the lights on. and the wipers, and the heater. this is confusing. im selling the car so i dont really want to buy any more parts than i have.

 

[badabing33a]

there is now a ticking noise while the car is running comming from the intake manifold. at first i thought it was comming from the head. but it wasnt. i put my ear over the intake mani and it was comming from there. now wtf is goin on?

 

[badabing33a]

its lost some power too. when i shift through 1st-3rd, i can hear the ticking following the rpms. why would the intake tick? maybe it is the engine making the ticking.

 

[steve]

The things that normally tick;
Hydraulic lash adjusters (incorrectly called lifters).
Fuel Injectors.
ISC when you turn the ignition on and off.
Solenoids on the filewall.

Thing that shouldn't tick;

Timing belt auto-tensioner.
Rod bearings.
Exhaust Manifold.

 

[bmx198706]

my car has the same problem.. first i turn idle up .. it fixed it for about a day or so.. then i thought it could have been the ecu.. well the ecu was fine.. turns out that its the idle air control motor.. may want to check tht. cause it sounds like the same issue as mine

 

[badabing33a]

ok, so i ground the timing adjustment connecter. is there a specific place to ground it? what about the one inside the car? then once i ground them, i adjust the BISS screw by turning it right to get a higher idle im assuming?

 

[swapped92talon]

I believe that all you need to do is ground the one in the engine bay. Thats how I set my idle and base timing. And you can ground the plug anywhere that there is a ground wire, such as the firewall, etc. Also, you'll turn the BISS screw out (to the left) to get the idle to increase. Good luck.

 

[badabing33a]

ok im getting ready to do that. i still cant figure out my the ecu is ticking crazy and why i lost some power. any ideas?

 

[Illmat1c]

1G BISS Adjustment

Shows you how to adjust the BISS the correct way.

 

[badabing33a]

ok i adjusted the BISS screw and it ran fine after a while. still seems to have a lost a little power up hill. but on a flat area, the car climbs to 90mph quickly. maybe the power loss is in my mind. idk. however, the oil psi reads just shy of normal (to the left of the lines on the gauge). the ecu might act up again. seems to happen to people with this problem since ive been searching the he|| outta the problem. thanks for the "how to adjust the BISS".

 

[brownfinger]

ISC motors can fail instantly. One day the car just won't idle, you'd have to heel-toe just to to keep it running at a stop light. New and used throttle bodies come with them attached, or maybe you could find a junk-yard where they don't realize that a new ISC is $300. I've bought a good used throttle body for $40 once. Like Steve says, a bad ISC could fry your ECU. You don't want that. Bad ISC motors are super-notorious. They only seem to last a max. of 80Kmi., usually. The battery (tires, too) is the only thing that has been replaced more often than the ISC on my car. I think my car has had as many ISC's as it has timing belts.