88crxsiturbo

Hello, I have a 91 honda civic and i'm having troubles with my idle when it's cold. When I first start it up in the morning it wont idle unless I keep the gas down some. If I let off the gas it will die instantly. But once the car begins to warm up and the temp. gauge goes up it will idle on its own, but then it will idle high, usually around 1500-1800 rpm. Any suggestion would be greatly appreciated.

Thanks

cruzalekz

sounds like a coolant temp issue or the thermostat is stuck open

is your engine light on?

88crxsiturbo

Sry it took me so long to get back to you! I just replaced the temp sensor about 2 mths ago actually, and the thermostat is new also with it being replaced around the same time as the temp sensor. I replaced the temp sensor b/c it was leaking, so I went ahead and replaced it while I had it out. As for the check engine light, no it isnt on.

88crxsiturbo

bump

ChrisS

It depends on what your definition of cold is:
-here in the SF bay area: anything around 32 F is cold
-in the NE United States: cold is -10 F and below.

I guess, you could get a plug-in heater that wraps around the oil pan. Put it on a timer. So, it comes on an hour or so before you leave for work.

How long does your car take to warm up on a cold morning?
(my '91 CRX Si takes about 1 mile of driving or maybe 5 minutes idling)

Take Care,
ChrisS

cruzalekz

i believe you have an idle air control problem which on your car i believe is coolant sensitive (temp sensitive). when your car is fully warmed up, the idle is still not good, well you have an adjustment for idle its a screw i guess around the throttle plate area. what i suggest is play with that screw when the car is fully warmed up and bring the idle speed down. if adjustments are made and it still idle high, then you might have a vacuum leak somewhere.

88crxsiturbo

I live in West Virginia, so a cold morning, then, would have been around 0-10 degrees. Now on the other hand, its fantastic out and around 40-50 in the morning and 60-70 in the afternoon. So it doesnt act up as much lately where its warmer. But to warm up my car it takes about 1 or 2 miles tops and its at operating temp. I have adjusted the idle screw b4 after it was at operating temp. but it will go back to idling high after a couple trips down the road.

88crxsiturbo

U say air control, r u talkin about the thing that bolts to the back of the throttle body, with coolant lines and operates from air temp. till warm?

A-series

^ The valve on the throttle body would be the FITV, fast idle thermo valve. It's purely mechanical in operation, and controlled only by coolant temp. However, even w/o that valve (if it was blocked off or not working at all) the car should be able to idle by itself when cold, just not such a great idle. There's another valve (I think this applies to your year also), the Electronic Air Control Valve, EACV which is controlled by the ECU for controlling idle.

It's possible that the high idle (although you adjusting the base idle w/ the screw makes it harder to say for sure) is caused by the FITV giving too much air when cold and maybe the fuel system isn't able to supply enough (for whatever reason) to match it - the fix being to remove it and screw it's internal plunger all the way in . Otherwise maybe the EACV isn't working until warm, although a properly running car would still idle w/o the EACV, it would just be very low (that's the base idle).

Just the first things that come to mind, as you clearly have an idle issue, regardless of the cold-start problems. They could be unrelated also. If you make sure the FITV is screwed in all the way, and get the base, fully-warm, idle set correctly (a service manual would have the exact rpm), it will then be easier to determine what the actual cold-start problem is.

88crxsiturbo

Well I dont have to worry about the idle issue anymore, I started my car the other morning and heard a knocking sound. I pulled the oil pan off and found out that all my mains were showing brass, and one rod was about to spin a bearing. So now im looking for a new motor. Hoping to find a different motor to go with, I already converted this motor to obd1 and ecu has the wiring harnes for vtec.

Thanks for all the suggestions.