`80 1500 civic w/keihen carb . orig owner , have tried timing , both fuel shut off valves , spark plugs , adj floats , chk needle & seats , ign switch , coil , etc , etc . wont shut off until i dump clutch or pull coil wire . thanks for any help .

 

This isn't a true case of "dieseling", or running withoug sparks. Since pulling the coil wire makes it stop, the ignition is still firing when it shouldn't. The coil should be completely dead with the key off.

So something in the electrical system is allowing power to feed back to the coil with the key off. This probably also is holding the fuel solenoids open. I think it could be related to the alternator if it isn't the key switch or some aftermarket wiring.

 

makes sense , i put a tester on both sides of coil & theres no light from both sides when i turn key off , also dis-connected tach , didn`t help , i wonder if it is the alt ? also when i pull wires on the fuel solenoids , it will shut off without run on with each one ?? someone said it could be the fuel & i should use 97 oct ? thnks

 

Clearly an electrical problem. Disconnecting the solenoids causes it to starve out, so if they turned off like they should in the first place, it wouldn't matter what kind of gas is in the tank.

Really does sound like the alternator is generating some voltage and feeding it back on the ignition wire during the run-on period. That's why you don't measure any if you just have the engine stopped. Try taking the belt off and spinning the alternator by hand (if you can do that fast enough) with the engine off to confirm that.

 

so spinning the alt w/ the engine off i should chk to see if it`s putting out power ? do i chk the output at the coil ? what if i take off the alt belt & try the run on that way ? ie - eliminate the alt turning all together . also the fuel shut valves do turn off & on with the key , but i cant see the seat in the rear one that has the brass needle type valve . the valve w/ the rubber plunger seems to work as i took the top of the carb off & it does hold fuel . one thing , i cant find anyone with the propane enrichment tool . do you think thats the only way to adj the carb ? thanks

 

That is a better test, take the alternator belt off and see if it runs on then.

I would not attempt to adjust the carburetor as long as the car idles and drives OK.

 

took alt belt off & still dieseled , actually saw motor run backwards for a sec