Ok, my car (85 TA LG4 M5) had been idling high (~1500-1750 rpm) since i bought it last summer. I tuned it up (replaced all plugs, wires, new dist cap/rotor, oil change, all filters, new EGR valve, new O2 sensor), and the problem was still there. I replaced the carburetor with a newly rebuilt one, and still had that problem, despite making adjustments to my fast and curb idle screws.

Last weekend, I replaced the choke heater relay, after reading another thread on the boards about someone with a similar problem. This worked, and the idle went down to normal (~700-750 rpm) and was able to drive it around without problems other than the fast idle being a bit low when I started it. Today, I readjusted my fast idle and curb idle to spec, and the TA idled perfectly fine for several minutes, and then it went back to its old high idle of ~1500 rpm.

One thing I have noticed since I got the car is the oil pressure guage doesn't seem to work properly. It's always maxed out. I can only recall one time when it did work correctly, and then my choke heater fuse blew. Could the high idle be related to a problem in the oil pressure wiring?

I'm convinced that the root of my problem is somewhere in the electrical system - I'm thinking something to do with the oil pressure sender. All input would be greatly appreciated.

 

The oil pressure sender won't have a switch unless there was an in-tank electric fuel pump installed sometime after it left the factory. Even then, it shouldn't have anything to do with the choke circuit.

I agree it sounds like you've got an electrical circuit issue. Have you verified the voltage at the choke?

 

No, but I have observed the choke butterflying opening from completely shut to completely vertical on cold starts. I can borrow a voltmeter though.

Whats weird is that the oil pressure guage actually worked one day a few months ago, and I didn't seem to have the idle problems that particular day. Could be coincidence, but I just thought I'd point that out. Sorry, I meant sender not switch in my 1st post.

 

The oil pressure sender only operates the gauge. It has nothing to do with anything else, so it's unlikely to be related to your problem.

 

ok, i'm gonna check out the wiring going to the choke heater relay, maybe somethings loose.

although unrelated to the problem, i'm guessing i need to replace my oil pressure sender unit, so my guage will function properly.

thanks for the replies.

 

i noticed that the part number of the ch. heater relay i pulled off is "14039662", and the one i put on is "14089568".

i looked on gmpartsdirect.com, and the original part no. is not valid. does anyone know if the one i put on, "14089568" is the right one? according to the parts tech at the local dealer, it's the one, but i just want to verify...

also, is there any way i can check to that the relay works or not? i haven't been able to work on the ta lately because its been raining pretty bad where i live, but it's a sunny weekend coming out, and i might work on the car.

 

I finally got a multimeter and was able to check this. My voltage at the choke is about 13.5 V, and the resistance is ~6 ohms. This is normal correct?

 

I finally got a multimeter and was able to check this. My voltage at the choke is about 13.5 V, and the resistance is ~6 ohms. This is normal correct?