throttle boddy clicking!!!! help!!!

AKPsiMC03 · #1 (**permalink**) 03-27-03, 11:34 PM

I got home from school tonight and i turned off my car. I heard a clicking noise so i opened the hood. Now the key was all the way off and i had them in my hand, but the throttle body was clicking open and closed!!! It does this too when i turn the ignition on but dont start it. I think its what is causing my surging when i drive.

someone please help me fix this. I ran the code scan on the DIC tonight and no codes only "history A037" whats that one?

but this throttle body opening and closing thing is getting on my nerve... oh yeah, it is moving on the cruise control cable, not the accelerator cable.

please help me!

Katshot · #2 (**permalink**) 03-28-03, 05:05 PM

That's a loss of IPC seria communication. Did you have the instrument cluster worked on? That's usually what that code's from.
As for the TB opening and closing by itself, that's a new one on me, sorry.

AKPsiMC03 · #3 (**permalink**) 03-28-03, 05:45 PM

i havent had it worked on... and the throttle body opening and closing... its not any cable pulling on it cus there is slack in both cables when it does it. Is the throttle plate motorized to work with an idle air control valve? Im pretty sure that is whats causing my car to surge at lower speeds.

eehoepp · #4 (**permalink**) 04-23-03, 10:46 AM

My 94 STS started doing this same thing.

It's the Idle Speed Control motor that's popping the throttle plate open and closed. I also believe this is what causes the surging. At one point it was "idling" at 3000RPM. Kind of tough to brake to a halt when the engine wants to go.

Have you found a fix yet?

I pulled code P027 History, which is " Open Throttle Position Switch Circuit". As far as I can tell from the service manual, the TP switch is built into the Idle Speed Control motor (this is not the throttle position sensor). The service manual (right now it's at home & I'm at work) also says that if you are in the PCM diagnostic mode, the climate control "LO" indicator shows the state of this switch. If the gas pedal is released, "LO" should show. If you press the gas pedal, "LO" should go off. If the pedal and "LO" indicator are out of sync, the car either has a wiring problem or a bad ISC motor.

I'm going to dig deeper into it tonight.

Katshot · #5 (**permalink**) 04-23-03, 11:19 AM

To be honest, I had forgotten that early Northstars used a ISC.
They are definately a PITA. They are a left-over from the old DFI engines and do tend to cause problems. The TP "switch" is in the ISC, and basically just tells the computer that the throttle is closed and that IT should now control the idle. The TP "sensor" is mounted on the end of the throttle shaft. The TP switch can be tested with an OHM meter. The ISC has 4 contacts in the connector, the A&B contacts are for the TP switch, and the C&D contacts are for the ISC motor. The switch contacts will show an open and close circuit when the plunger of the ISC is depressed and released. You should also feel a slight clicking (it's just a little micro switch). The motor circuit can be tested with test leads, battery, and ground. The motor is reversed via reversing the polarity. FYI; the motor is the same motor used on Kodak slide projectors to move the lens in and out.
The status light you're talking about is just an indication of what position the TP switch is in.

eehoepp · #6 (**permalink**) 04-24-03, 02:09 AM

And as abruptly as the ISC motor started clicking and fidgeting around... it stopped.

Hmmmmm...

I cleared the P027 History code & waited to see if it would return. It didn't. I find this bizarre, but I'm not complaining. At least I'm forearmed if it comes back.

AKPsiMC03 · #7 (**permalink**) 04-24-03, 04:32 PM

what did you do to figet around with it? mine onlty does it ocasionally.... it stopped compleetly for a while after i replaced the front O2 sesor that went bad. the rear still needs to be replaced. But my best guess was that the ISC was chasing a rich condition and trying to compensate for it, even after the car was turned off.

Katshot · #8 (**permalink**) 04-24-03, 05:14 PM

Unlikely. The ISC "should" open the throttle slightly after the engine shuts down.

BlownC5 · #9 (**permalink**) 05-10-03, 05:31 PM

Mine is doing the same thing. Anyone know a fix for this? Thanks

eehoepp · #10 (**permalink**) 05-18-03, 02:00 AM

I forgot to include something in my previous post. The ISC pushes on the throttle with a hex-head screw. I tightened that screw into the ISC until it bottomed (FWIW, it was 20 times one sixth of a turn if I ever have to put it back). I knew it wasn't the best way to deal with it, but I needed to get home from work (20 miles) and the 3000RPM surge in traffic was risky.

It still surged a bit on the drive home & it still clicked after I shut it off that night. But after that, it stopped. To me, it almost seemed like it was trying to re-calibrate itself, but I have no idea if the PCM is capable of doing that. I haven't had a problem with it since.

I don't think this is "the" fix, but it seems to have worked for me.

Katshot · #11 (**permalink**) 05-18-03, 08:23 AM

Eric,
The ISC plunger being screwed all the way in only limits the amount of total length it has available to set the proper idle. The in and out movement has nothing to do with it. You need to set "Min. Air" and that will "calibrate" (mechanically) the ISC so the ECM can then set the proper idle. The procedure is in the service manual. It's easy and I could talk you through it but just in case I forget a step, I'd rather have you do it by the manual to be sure.

BlownC5 · #12 (**permalink**) 05-18-03, 08:53 AM

Could you post that procedure Kevin? Thanks

iscoutit · #13 (**permalink**) 02-04-04, 01:24 AM

my friend has the same problem and I found out the answer. the answer is a technical service bulletin from GM. TSB # 47-60-07

YOUR THROTTLE BODY IS DIRTY AND IT MUST BE CLEANED WITH SOME CARB CLEANER YOU DON'T HAVE TO TAKE IT OFF BUT IT MUST BE CLEANED.THIS IS THE BULLETIN ALMOST EXACTLY SO IT SHOULD HELP.

THE CAUSE IS THE ISC MOTOR RATCHETING IS CAUSED WHEN THE MOTOR IS COMMANDED TO EXTEND BEYOND ITS MECHANICAL LIMIT. WHEN THE TP SENSOR LEARN IS CORRECT (AT MINIMUM AIR, THE THROTTLE LVER RESTS ON THE MINIMUM AIR SCREW) AND THE ISC MAXIMUM EXTEND POSISITION IS PROPERLY ADJUSTED, THE MOTOR WILL NOT BE COMMANDED TO MOVE BEYOND THE MECHANICAL LIMIT.

IDLE CORRECTION:
THE THROTTLE BODY BORE AND BLADE SHOULD BE CLEANED AND RELEARNED USING THE FOLLOWING PROCEDURE:

!!IMPORTANT IF IT IS SUSPECTED THAT THE ISC MAXIMUM EXTEND POSISTION HAD BEEN ADJUSTED WITHOUT CLEANING THE BORE, IT SHOULD BE CHECKED AND READJUSTED IF REQUIRED. CLEANING THE THROTTLE BORE SHOULD BE PERFORMED BEFORE PERFORMING THE IDLE SPEED CONTROL SYSTEM CHECKING PROCEDURE.!!

THROTTLE BODY CLEANING PROCEDUTRE:
1.REMOVE OR DISCONNECT AIR INTAKE DUCT
2.INSPECT THROTTLE BODY BORE AND PLATE FOR DEPOSITS.IT IS NECESSARY TO OPEN THE THROTTLE TO INSPECT ALL THE SURFACES.

3.CLEAN THE THROTTLE BODY BORE AND PLATE USING A CLEAN SHOP TOWEL AND CARB CLEANER THAT DOES NOT HAVE METHYL ETHYL KETONE IN IT (MEK).

4. REPLACE INTAKE DUCT

FOR G-CAR RUN TECH 1 TP SENSOR AND IDLE LEARN PROCEDURE

FOR E,K,OR K SPECIAL:
1. ENTER DIAGNOSTIC;SELECT PCM OVERRIDE PS13
2. PRESS THE COOLER BUTTON
3. KEY "OFF" FOR 30 SECONDS (DO NOT EXIT DIAGOSTICS)
4. PERFORM TP SENSOR / IDLE LEARN PROCEDURE