Park idle wonkiness

[RI86DX]

If I leave the car sitting in park for an extended period of time (15-20 mins) my car will bog down to about 100 rpm and almost die, then if I do as little as depress the gas pedal a nose hair, the fast idle kicks on and it flies up to 2K. Also sometimes when I cold start the car up I can't shut the fast idle in park off by goosing the throttle, I have to take the car out and drive it around until the motor's warmed up, then it'll idle at a grand in park perfectly.
Should mention I'm on the stock Keihin feedback carb with vac intact. No Weber or vac delete.

[RI86DX]

Sitting in the garage today goofing with my shot-to-shit tape deck I got from some ghetto junkyard seeing if I could get the door to close with a tape inserted sitting in park with the motor warmed up, same thing after about 10 + mins of idling. Vac leak? Fuel cut off solenoid?

[Oldblueaccord]

Did you notice where your temp is at? If the motor doesnt have a thermostat it could be running cold, or on extended idle it could be over heating a little. Carbs with modern gasoline dont play to nice anymore there not formulated for it. I would also try the next level octane up.

[RI86DX]

Did you notice where your temp is at? If the motor doesnt have a thermostat it could be running cold, or on extended idle it could be over heating a little. Carbs with modern gasoline dont play to nice anymore there not formulated for it. I would also try the next level octane up.
Temp gauge stays right where it should be. I'll try putting 89 in it next time I fill it up. One breezy cool-ish evening in August however pulling into the garage I noticed the temp gauge moved up just past the mid point, enough for the cooling fans to kick on. First and only time that ever happened.

[ShiRen]

Don't bother looking at the temp gauge, it's nowhere near accurate. Fans are your best indicator... But that's only at like 200. If the fans are on and the gauge is in the top quarter then you have a problem

As for your carb, stare down it's throat and make sure the choke is opening. While the air cleaner is off, watch the fuel level.

[Oldblueaccord]

Don't bother looking at the temp gauge, it's nowhere near accurate. Fans are your best indicator... But that's only at like 200. If the fans are on and the gauge is in the top quarter then you have a problem

As for your carb, stare down it's throat and make sure the choke is opening. While the air cleaner is off, watch the fuel level.

What if your fans dont work correctly?

[RI86DX]

Don't bother looking at the temp gauge, it's nowhere near accurate. Fans are your best indicator... But that's only at like 200. If the fans are on and the gauge is in the top quarter then you have a problem

As for your carb, stare down it's throat and make sure the choke is opening. While the air cleaner is off, watch the fuel level.

The car has never exhibited symptoms of overheating/running too hot, that's the thing. When the gauge moves up to the middle after the motor warms up, I can keep my hand on the middle of the hood for at least 5-10 seconds before my hand is too warm to keep on, and that's right after I shut it down, the hood cools off pretty fast. I think it's defo a carb issue, not a cooling/tstat problem.

[ShiRen]

What if your fans dont work correctly?

I meant the fan is an indicator of actual temp, if the gauge is at the top it is overheating, but nowhere in between, unless the gauge is broke too.


The car has never exhibited symptoms of overheating/running too hot, that's the thing. When the gauge is in the middle after the motor warms up, I can keep my hand on the middle of the hood for at least 5-10 seconds before my hand is too warm to keep on. I think it's defo a carb issue, not a cooling/tstat problem.

I mean I wouldn't expect it would unless you were having issues that sounds like a head gasket.

It does sound like a carb issue, or a black box issue. Is this an auto or manual? There might be something wrong with fast idle circuit or choke, you might have to delete the fast idle solenoid and set the idle to about 1k manually, that might act a little wonky if it's auto though.

[RI86DX]

I meant the fan is an indicator of actual temp, if the gauge is at the top it is overheating, but nowhere in between, unless the gauge is broke too.



I mean I wouldn't expect it would unless you were having issues that sounds like a head gasket.

It does sound like a carb issue, or a black box issue. Is this an auto or manual? There might be something wrong with fast idle circuit or choke, you might have to delete the fast idle solenoid and set the idle to about 1k manually, that might act a little wonky if it's auto though.
Yeah, it's a 4spd auto. My second guess was something retarded like a pinhole sized vacuum leak being enough to make it wig out, knowing how temperamental the stock setup on these cars is.

[Oldblueaccord]

The car has never exhibited symptoms of overheating/running too hot, that's the thing. When the gauge moves up to the middle after the motor warms up, I can keep my hand on the middle of the hood for at least 5-10 seconds before my hand is too warm to keep on, and that's right after I shut it down, the hood cools off pretty fast. I think it's defo a carb issue, not a cooling/tstat problem.

Carburetors run on certain engine operating temperatures. Cold engines need choke. Warm engines dont. There is also problems with fuel/vapor lock esp if your engine is running a little to hot. Thats where fuel injection has some advantages. Fuel is not made for carburetors at all they havent been produced on a stock vehicle since 1994. They all have there quirks.

Thats all I am getting at.

[RI86DX]

Carburetors run on certain engine operating temperatures. Cold engines need choke. Warm engines dont. There is also problems with fuel/vapor lock esp if your engine is running a little to hot. Thats where fuel injection has some advantages. Fuel is not made for carburetors at all they havent been produced on a stock vehicle since 1994. They all have there quirks.

Thats all I am getting at.

Right, I hear you loud & clear. Like I said, I'll try putting 89 in her next time I get gas. Haven't drove for almost a week. And yeah, as far as the US goes, last US market veh with a carb was the '94 Isuzu Pickup. In developing countries such as Indonesia, the Philippines & South Africa you could get carbed vehicles well into the 2000's. I know Mitsu Express vans were carbed until 2003 in Australia as well. Honda used their PGM-CARB system until MY 1996 as well outside of the US/Canada.

[RI86DX]

Alright, so now that it's been cold as fuck out, I can leave the car idling in park indefinitely. It's only when it's warm out that it does it. AFR problem? Tstat? O2 sensor?

[Oldblueaccord]

Alright, so now that it's been cold as fuck out, I can leave the car idling in park indefinitely. It's only when it's warm out that it does it. AFR problem? Tstat? O2 sensor?

Look and see if the choke is still on a little. if it is then it likes richer mix at idle.

[ShiRen]

Look and see if the choke is still on a little. if it is then it likes richer mix at idle.

The choke doesn't really have a brain... The whole partial operation is actuated by a bimetallic steel winding, the engine should get hot enough that it opens up. However, if it was stuck partially closed that can make a big difference on hot/cold operation. Not sure if that would behave like this though, it could also be a constant stream of fuel coming out of the accel pump orifice. Op hasn't really reported back on anything we had suggested previously, so hard to narrow it down

[RI86DX]

Came across this old thread:
https://www.3geez.com/forum/showthread.php/78166-carb-idle-issues-caused-by-carb-temp-sensor-discuss/page1
Yet another thing to look into/consider.