[jbrody44]

I am Idling all of the sudden at about 2800-3000 RPM!!! I tried adjusting my idle screw and sent it all the way in with no help. I tried resetting the ECU (I don't know why, but hey ya never know) still no help. Anybody have an idea, could something be sticking? Could a bad TPS cause this as mine is suspect. Thanks for any feedback.

 

[Dave A.]

Maybe something is causing your throttle to not close properly at idle, like a binding throttle cable or something?

 

[jbrody44]

It doesn't look like the cable is binding up. The trottle control is resting right on the stop screw, yet the idle is around 3000 rpm. I am still stumped I am going to look at it some more today.

 

[Fieldstown Kid]

The manual says the TPS is a possibility. (Others include: Fuel Pressure Regulator, Cold Start Injector, Injector Leakage.)

Here is the TPS voltage levels at ECU with ignition ON:

IDL-E2 Throttle vavle open 4-6v
VTA-E2 Throttle valve full closed 0.1-1.0v
VTA-E2 Throtte valve full open 4-5v
Vc-E2 Normal 4-6

No voltage at any indicates a problem.

No voltage at IDL could be bad wiring to ECU or to TPS.
No voltage at VTA could be bad wiring ECU E1.

I have the other problem, idling at 500 and cutting out. Adjustment screw maxed out. Looks like the accelerator cable is stretched and the nylon grommet at the pedal is mashed.

Good look.

 

[sloopercat]

Look for a vacum leak. Check any/all of the hoses. The PCV hose was bad on mine. The accordian pipe that goes over the valve covers has been known to develop cracks. You might clean up the throttle plate, could have gunk that is preventing it from closing. If it was me, I would dissasemble the AFM to throttle body hose and check for any loose or cracked stuff. It could also be the ISC valve, since what that thing does is control idles speed, lots of stuff to check on. Do you have a TSRM?

 

[jbrody44]

Thanks for the input everyone, I have some serious detective work to do I see. I Don't have the TSRM but I know where the on-line version is. I will have start checking this stuff out later this afternoon (if we don't get the thunderstorms that are forecasted anyhow). I will update with what I find.

 

[MAD_83supra]

I am Idling all of the sudden at about 2800-3000 RPM!!! I tried adjusting my idle screw and sent it all the way in with no help. I tried resetting the ECU (I don't know why, but hey ya never know) still no help. Anybody have an idea, could something be sticking? Could a bad TPS cause this as mine is suspect. Thanks for any feedback.

Mine did the same thing a couple of times. Both times it was a stuck idle control motor . Its supposed to increase the idle when you turn on your AC . Mine was stuck open so I just blocked off the bypass hose. ( The black rubber hose that goes from the air intake pipe to the round eletrical motor looking device that sits on the intake plenum , right next to your TPS..

 

[jbrody44]

Well, I went out and did some work on the idle problem. I took off the intake tubing and it all looks good, I cleaned my throttle body and all passages while I was in that area. All vacuum lines look good, replaced a few toyota hose clamps with standard ones. I then messed around with the TPS, I got the idle down to about 850 or so by messing with the TPS. I took some resistance reading (per Haynes as I don't have the TSRM and I was not really sure where to fetch the voltage readings from). Anyhow the TPS will only get down to about 14 ohms and then no continuity at all, I should be able to get it down to .2 to .8 or so at idle. Once I have the idle down where it should be by messing with the TPS, the car does not really decellerate the way it should, it winds nicely down to about 1500rpm (in gear) the kind of drops out. So I think I will replace the TPS as it is definitely quirky. I am interested in checking ou the idel control motor as this sounds like a prime candidate for my problem here. Sounds like I may have a compound problem TPS, Idle control motor, and who knows maybe more! Thanks for the input so far, I will go check out that Idle control motor now. Sorry for the long babbling post.

 

[sloopercat]

The TPS sends a signal to the ISC, sounds like you may have found the culprit. I understand that it is not unexpected for the TPS to go out.

 

[jbrody44]

Anybody know of a good source for a new TPS? Is this a dealer item? Thanks

 

[Melly]

My Car had the same problem. Try Replacing your throttle Body Sensor if you have allready not.. The plastic they used in the sensor is old and will be brittle. Mines broke when i was just cleaning it.

 

[zank]

My Car had the same problem. Try Replacing your throttle Body Sensor if you have allready not.. The plastic they used in the sensor is old and will be brittle. Mines broke when i was just cleaning it.

Isnt it called the Throttle Position sensor :wink: