high idle problems
#1
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Car: 1985 Trans Am
Engine: 305 LG4 boat anchor
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Axle/Gears: 3.27 "Down Under" 9-Bolt
high idle problems
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.
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.
Last edited by jordeezy; 01-24-2008 at 02:16 PM.
#2
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Car: 82 Berlinetta/57 Bel Air
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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?
I agree it sounds like you've got an electrical circuit issue. Have you verified the voltage at the choke?
#3
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Car: 1985 Trans Am
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Re: high idle problems
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.
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Re: high idle problems
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.
#5
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Car: 1985 Trans Am
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Re: high idle problems
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.
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.
#6
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Car: 1985 Trans Am
Engine: 305 LG4 boat anchor
Transmission: T5
Axle/Gears: 3.27 "Down Under" 9-Bolt
Re: high idle problems
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 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.
#7
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Car: 1985 Trans Am
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