87 GL Idle/Warm Up Issues

[sunflowersubaru]

87 GL WGN 5SP MT 4WD Carb.

 

Basic problem is that until it warms up a bit, engine idles rough. In the colder months, winter especially, idle is unsustained without continuously pressing on the gas peddle until it warms up. In the summer it will idle without pressing the gas peddle as in the winter but only at 50 rpm, the first line above zero. Once it warms up, it idles nicely at about 700-800 rpm.

 

With engine cold and thinking it might be overchoked, inserted long screwdriver into carb throat to hold allow more air flow but it would not start. Removed screwdriver and it started but still being cold, idled, rough and barely.

 

With engine still fairly cold, disconnected the temperature sensor wire, no change. Waited until the engine warmed up and removed it again, car continued to idle ok and the temp guage went to zero. Re-connected the temperature sensor wire and the temperature gauge came back to normal.

 

New radiator, thermostat, and water pump intake hose this past February - no more coolant leaks.

 

Thank you.

[morf]

My 87 GL does the same thing. I've heard it could be the coolant temp sensor. Not sure though as I haven't got around to messing with it.