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Too High Idle Cold Then Too Low


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#1
syngen smyth

syngen smyth

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  • Car: 1983 626 coupe 5 speed
Looking for clues on this one! Here are the symptoms:

1- On start up, when cold, the idle goes right to about 2200. It will climb to over 3000 if I don't keep hitting the gas. Even then, I can not get it to under 2000 until it warms up
2- After warm up, it will idle really low; 600 maybe with intermittent almost stalling
3- If you turn the a/c on, at idle it will pulsate 700-1500, over and over about a 2 second cycle.

Any clues anyone? thanks....

#2
chief tool

chief tool

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  • Car: 1984 GC FE-T & GC RF Diesel
check the automatic choke (assuming it has one) that might explain the high cold RPM.....600 when hot is close to nornal, might a need lifting a little to 750.

As for the a/c, there is an idle up valve, which is meant to raise the engine speed to about 1200, maybe the valve is not always working ? i.e sometimes the compressor clutch engages without the idle up valve turning on at the same time, hence the low idle, then maybe some other times it does work, and the speed is on the high side of normal (which you can adjust down by the way)

However you might have a worn thottle body which can cause variable idle speeds warm or cold, check for lateral play in the throttle shaft, high mileage city driven cars usually have this problem.

and on a side note, probably only James Bond fans would understand your forum name :)

#3
syngen smyth

syngen smyth

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  • Car: 1983 626 coupe 5 speed

check the automatic choke (assuming it has one) that might explain the high cold RPM.....600 when hot is close to nornal, might a need lifting a little to 750.

As for the a/c, there is an idle up valve, which is meant to raise the engine speed to about 1200, maybe the valve is not always working ? i.e sometimes the compressor clutch engages without the idle up valve turning on at the same time, hence the low idle, then maybe some other times it does work, and the speed is on the high side of normal (which you can adjust down by the way)

However you might have a worn thottle body which can cause variable idle speeds warm or cold, check for lateral play in the throttle shaft, high mileage city driven cars usually have this problem.

and on a side note, probably only James Bond fans would understand your forum name :)


so i have been trying to figure this out- wayy too many vacuum lines for me. it makes for too many combinations of possible problems. is there anybody who had just ripped all this stuff out and put a simple replacement carb on this engine? something with a throttle cable and that's it? i would even love to have a manual choke.

#4
chief tool

chief tool

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  • Car: 1984 GC FE-T & GC RF Diesel
for starters just check to see if there are any lines that are not connected to anything.

Here in Oz our 83 models all had manual choke, but our emission regulations were pretty lax until about 1986.

There is a weber 32/36 carb plus adapter kit available for these engines, but theyre a bit pricey for what they are.

Is your car another one of these west coast US models with an O2 sensor hanging out of the exhaust manifold ?




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