boxerlover Posted April 30, 2006 Share Posted April 30, 2006 I'm having some troubles with cold starting and idle with my '86 4WD wagon. It starts hard and won't idle reliably under 1100 rpm or so. The choke was missing a clamp screw and rotates freely so it's way out whack. I want to get it set right again, but my rotten Chiltons manual does not cover the electric choke version of the carb. Can anyone help? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted April 30, 2006 Share Posted April 30, 2006 The 85/86 electric choke module's usually wear the end off the bi-metal spring inside them from rubbing on the choke plate lever. Likely the end of the spring is broken off and you'll have to replace the electric choke module. Look for one in the junk yards - hard to find without a broken end. If you can find a car that was garaged it should be ok, as the choke was not used much. Take out the rivets, or the screws or whatever is holding the choke on, and inspect the spring. If the hook on the end is good, then just turn the choke housing till the spring holds the choke plates closed with the engine cold. Make a slight bend in the ring that holds the choke module on the carb, and screw it on so it clamps down on the housing and holds it from moving. GD Link to comment Share on other sites More sharing options...
boxerlover Posted April 30, 2006 Author Share Posted April 30, 2006 Thanks General Disorder. I'm going to do battle with it right now. I'm assuming that the choke should have 12V to it whenever the engine is running. Coreect? Link to comment Share on other sites More sharing options...
boxerlover Posted April 30, 2006 Author Share Posted April 30, 2006 Success! It fires right up now when cold. Now if I could just get it to idle hot... Link to comment Share on other sites More sharing options...
mcs Posted April 30, 2006 Share Posted April 30, 2006 I've always wondered why is there 12Volt at the choke, surely its just a spring that shrinks when it gets cold causing the lever to be pulled. :-\ in my brain this does not compute :-\ Link to comment Share on other sites More sharing options...
GeneralDisorder Posted April 30, 2006 Share Posted April 30, 2006 The 12v is for the heating element behind the spring - it's like a toaster coil. It heats up the bi-metal spring slowly, and pulls the choke off after the engine has had a chance to warm up. Not a perfect system since there is no real correlation between the engine temp and the choke temp - if the engine is warm then the choke hsouing will get warm just from proximity, but if the engine is cold, and the ignition has been on for a short time the choke could pull off without the engine ever being started. In practice it works alright tho, and is definately less complex than the coolant heated choke sytems, and requires less driver input than a manual choke. GD Link to comment Share on other sites More sharing options...
mcs Posted April 30, 2006 Share Posted April 30, 2006 So does that mean that its best to heat the coil before setting the choke position so when its cold it gives maximum reach and when warm returns to the chosen resting point ? USMB rules Link to comment Share on other sites More sharing options...
GeneralDisorder Posted May 1, 2006 Share Posted May 1, 2006 No - best to start the car immediately as the choke will be correct for the outside temp conditions (assuming it's set correctly to begin with). If you leave the ignition on, then the choke will be "pulled off" and it will start without a choke at all since it thinks the engine is already warm. One of the other reasons the electric choke is not the best is that it does require adjustment for temp extremes - like it may need to be set differently for extremely cold climates, or extremely hot climates. Theretically, a coolant choke should be better, but in practice it doesn't seem to work that way. Another thing - some soobs - mostly the feedback carb ones, run the choke from the fuel pump control unit circuit. This has the advantage that the choke will not get power unless the engine is running, and a tach signal is present. This improves the behavior of the electric choke quite a bit - still does nothing to improve the adjustment for extreme climates problem - only full Fuel Injection can really solve that easily. Yay for choke theory! GD Link to comment Share on other sites More sharing options...
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