E4me ccc fast idle

[Bud]

Have a question about my fast idle since the weather has warmed up some I've noticed my fast idle is not the same as it was when I start it idle goes up but then you can hear it go down not really a stumble but you can tell it goes down then comes back up until you work the pedal the fast idle doesn't seem like it's as high as it was 1500 now around 2000 before this started today when I started instead of coming back up it went down more and stalled the car but restarted and it idled up and kicked down I have checked the choke pull off holds vacuum and adjusted the choke and checked to make sure the throttle opens have not adjusted the fast idle yet cannot figure out why it would have changed and the car run good when driving this may not even be a carb problem not sure was also thinking about the efe valve in the exhaust what's your take on this

[Cliff Ruggles]

The throttle shaft position is controlled by the fast idle cam when the choke is on.  Some cams have one step, others 2, 3 or even 4. 

If it's on any particular step as it warms up it may idle at a different speed.

Engine speed will also vary some as it warms up as the choke flap opens and the intake heats up.

Doesn't rule out problems in other areas, vacuum leaks, EGR, timing, etc......Cliff

[Bud]

Little hard to explain but it does this when its on the highest step of the cam so idle should stay high until you kick it down but when the idle goes up it will come back down and then go back up until you kick it down I give it one pump to set choke and fuel shot to start but yesterday when I started fast idle was high but then it went down and didn't come back up like its been doing and the car stalled but restarted and then did the high then low then back up until I kicked it down this is just something different that it hasn't been doing noticed it when the weather has warmed up as far as timing it's not been changed and runs and starts ok doesn't seem to have any vacuum leaks either the egr is not stuck and can move it with my hand also no check engine light either one thing I'm not exactually sure is working right all the time is the efe valve I can usually hear it close when I shut the car off after driving but there have been some recent time that I couldn't hear it this is a 87 Monte Carlo ss and this does seem like a sort of strange problem any way thank you for your time

[Cliff Ruggles]

If it drops off the high step it should not go back up there for any reason, unless the electric choke isn't heating up like it should.

Having the RPM vary some on the high step would be normal, as the choke flap opens and intake heats up, but it should be on the high step very long.

I spent some time adjusting the electric choke on my carb and ended up using a pretty light setting since the car is mostly driven in warmer weather.  I'm just a little impatient and don't like to sit there very long waiting for it to open and idle down so I can back the car out of the shop and drive it.

It did take me quite a while to find the ideal setting for the way I use the car, but once I nailed it down choke operation is pretty much flawless. 

The only problem I have is that the intake is cold (no heat crossovers in the aftermarket aluminum heads) so it can be a little off in really cold weather and require some "heat soak" before the engine will idle well.

Something I've learned to deal with as I've been running these heads for nearly 20 years now......Cliff

[Bud]

I think choke adjustment may be my problem I adjusted it so it closes shut when work throttle and when the pull off will open throttle about 1/8 inch guess I need to physically make sure it's on the highest step one thing I'm not exactly sure of is how tight the throttle needs to be when it closes guess I'll have to play with it

[Bud]

Can you give me the best procedure to adjust the choke.

[Cliff Ruggles]

The pull-off setting is equally as important as the choke setting.

The choke is set with the engine cold, loosen the screws, apply the throttle so it's not preventing the choke flap from closing.

Turn the choke clockwise until it's open, then CCW until it just closes the flap, then another couple of degrees.  That would be the minimum setting.  Look at the choke, most have a line on them that is lined up with the reference marks on the housing.  That line, if present should be in the middle of the range.

Just as the flap closes also make sure the fast idle cam is raised to it's highest position.  Tighten the screws, push the throttle once or twice, fire up the engine and very quickly adjust the pull-off and fast idle speed.

On the high step it should be around 1400-1800rpms, some literature will show higher numbers, but that's where I like to set them.

Fine tune the pull-off so the engine is happy.  Too far closed it will "blubber" rich, too far open it will stall out.

Blip the throttle so it falls on the second step, the engine should stay running.  If the pull-off setting is too lean it may stall.

The choke flap should be fully open in a couple of minutes and the fast idle cam should drop out putting you on the curb idle screw.

It usually takes 3-4 attempts from a cold start to nail down the best settings.  If you need the choke on longer turn it CCW.

Outside temps play a role in choke adjustments.  If you are setting it on a hot Summer day vs bitter cold Winter day, etc. 

I don't start my engine much in the really cold months, so the setting is a little "lighter" and the pull-off opens the flap further than would be ideal for really cold weather.  Sometimes it will stall out once if it's really cold outside, or if I try to move the vehicle before the engine is warmed up, but it's flawless in the warmer weather than I typically use the vehicle in.......Cliff

[Bud]

Cliff have another choke question I adjusted the choke awhile back and thought I had it working good but I went to drive the car yesterday pushed the pedal down once and cranked it over didn't start gave it another pump and car started but had no fast idle at all thought that's strange drove it and it ran ok so today I try it again same thing work pedal twice it starts but no fast idle it stayed running but is it not strange for it to no have fast idle now I did listen for the mc solenoid and its clicking and also checked to make sure the pull off was holding vacuum it was and that the throttle blade was opening wasn't able to check voltage on choke coil or if the throttle is going on the high step when I first start it yet any thoughts on why it did this ? Just seems odd to me worked fine until yesterday and today thanks

[Cliff Ruggles]

Is the weather a lot warmer now than the last time you set the choke?

[Bud]

Its probably around 10 degrees warmer it's in the 90s here now wasn't hardly that warm when I set it I know it doesn't really need fast idle in summer but shouldn't it still work? Or is the weather making that much different with the choke coil.

[Cliff Ruggles]

I wouldn't think 10 degrees would make much difference.

My carb has an electric choke on it, and it took a couple of adjustments to find the "sweet spot" so it works fine year round. 

In really hot weather it's not on the fast idle very long at all.....Cliff

[Bud]

Ok so this evening i pulled air cleaner off and worked throttle to see if it went on the high step it did so I adjusted the choke again I so figured that would make a difference it didn't still really didn't have fast idle but it was on the high step and I've not adjusted fast idle screw any so does this make sense? Why isn't the fast idle working only thing that's different is its warmer now but it should still work right. It was working same every time I started it until it sat for about a week then when I started it was different .