Slow idle on cold days

[Stocker]

Mine must need a bit more work besides this, then - throttle response is sometimes good, sometimes not, and my 16 MPG in rural (not straight highway) driving has given way to 12 in the winter - approaching what my carb'd, chokeless Buick got with a bigger engine.

I have the idle set properly now, I think. When it works it feels like the right speed both cold and warm. I still haven't figured out why the choke only engages intermittently but it's been better the past few days. Hopefully I can find someone to work the pedal for me while I watch the mechanism.

[DerekTheGreat]

If I just bought your car I'd just start by ripping the TB & EGR valve off and cleaning out all of the carbon chunkies and what not. Then I'd replace the throttle position sensor, choke-pull off mechanism and then lube all of the linkages. Replace fuel filter & run some injector cleaner through it and see what that does. That right there essentially made my car reliable. Before that it was stall city unless you adjusted the RPM to twice what Ford specified. Also, be sure that the vacuum hose routing is correct. I found that a few of my lines were mixed up. Once I corrected that I had a correctly working VOTM (Dashpot on drivers side throttle body) and much more predictable car. If that choke pull off mechanism and diaphragm are in bad shape those things wont work right. When vacuum is applied to the diaphragm it is supposed to "pull off" and disengage the choke mechanism but if there is a leak or the routing of the vacuum lines is wrong then that might not happen, leading to a sticky & high idle. That will cut MPG's. I lost a tad of throttle response off the line when I adjusted my car down to ~450rpm but the MPG's went up and it was easier to drive the car with the A/C on in stop & go traffic. That car also ate two compressors before I sold it. Don't know what would cause a car to continuously size a compressor, maybe not the right PAG oil?

[gadget73]

Winter mix fuel doesn't help any. Bad oxygen sensors on these also make them suck more fuel. doesn't usually seem to affect anything other than mileage though. Vacuum leaks will make it eat fuel too.



These don't use PAG oil. They ran mineral oil with R12, or you use ester oil with a 134a conversion.

[DerekTheGreat]

I paid a shop to convert and then throw a compressor and accumulator at it and it was fine for about a month the first time and then a week the second time. Maybe they did something wrong but they converted my Firebird three or four years ago and I haven't had any issues with that.

[Stocker]

Thanks for the input guys.

[DerekTheGreat]

Stocker, any updates?

[Stocker]

Now the fast idle mechanism is back to intermittent. If I open the hood to look at it, it will always work. When I want to drive the car, it's hit or miss. Hasn't been a problem lately since it hasn't been all that cold.

[DerekTheGreat]

You probably need to replace the bits inside that hockey puck, sounds like that spring inside it is sticky or at least out of adjustment.