85 nissan 720 dies when not pushing on gas or cruising.

[willhill92]

I just replaced the carb with a reman hitachi and it dies when i let off the gas , when I unplug ecu it doesnt do this but idles very high.

[]2eDeYe]

Bad idle solenoid?

[datzenmike]

The feedback carb was also notorious for the round electrical plug wires breaking internally. Probably to save a dime they made them too short and they don't bend properly when removing the air filter. Over time the wires just break inside. Very possible its the idle cut solenoid. Turn the ignition on offonoff and listen for a clicking sound. That's the solenoid... or lack of solenoid. Without it there is no fuel to the idle circuit... and no idle.

 

Disconnecting the ECU forces the carb into a default 'limp home' mode. Because the carb can run very lean fuel mixtures and over rich condition is used to safeguard the engine till it can be fixed.

[willhill92]

Thanks for the info I thought maybe i needed to replace the ecu but im going to have a friend go to start it while I listen near the carb because that sounds about right, well see. Thanks.

[willhill92]

Is the idle cut solenoid attached to the carb? because it seems unlikely that national carbs would send me a carb with a bad part on it.

[datzenmike]

Don't start... just turn to ON then off, on, off. Power to the idle will cause a click sound when the solenoid is energized. The solenoid may be fine but power not getting to it, check lead with meter if not.

[]2eDeYe]

Is the idle cut solenoid attached to the carb? because it seems unlikely that national carbs would send me a carb with a bad part on it.

 

 

Yes it is. As Mike said it could be a bad wire to the solenoid as well.