Throttle position sensor

[Bunky]

Does a 1986 Grand Prix 3.8 have a throttle position sensor and if it does where is it located ? Idle goes up and down, runs rough and sometimes will stall in park or drive. Could this be the problem ??
Thanks.

 

[rustyroger]

More likely it's the idle air control, located on the throttle body. Check out "pontiacbonnevilleclub.com" for more information. It's a forum that is mostly all about H and C Bodies, all of which are powered by fuel injected versions of the Buick 3800 engine.

Roger.

 

[Bunky]

Thanks for the reply. This is a 1986 Grand Prix with a 3.8 carburated engine. I was told that it's a Buick engine. I don't know much about engines but I don't think one with a carb would be much like a fuel injected version but I'm probably wrong.
Thanks again, Roger
bunky

 

[rustyroger]

You do have a Buick engine, in fact one of the best engines GM ever made, despite its strange and convoluted history.

If it is carburetted it wont have a TPS, I think you may have a vacuum leak though, you are describing the symptoms. Try spraying WD40 or similar around the carburettor and vacuum lines while the engine is running, if spraying in one particular place noticeably affect the way the engine runs you have found your leak.

If that doesn't work then a methodical tune up should reveal the problem, correct timing, good plugs and wires, and a properly set up carburettor breathing through a clean air filter and your engine will be a delight to your ears. Your gas mileage will improve too if it was much off tune in the first place.

Roger.

 

[turboaudi]

hi 86 gp 3.8 has a tps it is in the carb the wiring comes out of the driver side front of the carb if you can find a scan tool check for codes the idle circuit is probably gummed up or you have a vacuum leak the egr stuck will also cause this

 

[Bunky]

Thanks. If it's in the carb, I guess that means the top of the barb has to come off, huh. Not sure I want to tackle taking the carb apart. Is that what the 3 wire connector in the upper right front corner of the carb is for ? Thanks for the info. I really appreciate it !

 

[MeanBuicks]

In the image below the TPS connector is the white one on the right. Accessing the TPS does require partial disassembly of the carb. The blue connector is for the mixture control solenoid.

 

[Bunky]

I hope that's not the problem because it looks like a little more than I can handle. I can do most other repairs but unless the top of the carb just comes up and off without springs and seals and diaphrams shooting everywhere, it is probably beyond my ability. Thanks for your help. I appreciate it.

 

[rustyroger]

Well I was wrong.
On the other hand I've learned a little today. I never knew Any carburettors had a TPS. 😳

Thanks guys. 🙂

Roger.