After sorting through my issues on my 69 bb including sorting out choke issues and getting the dizzy rebuilt, the last issue was the occasional dieseling/ run on issue. This would occur 1 in 10 drives and would annoy me. Adjusting the timing and idle speed helped but it didn't eliminate the issue completely. I had to run the idle too low and explains why when I purchased the car is idle  was low as the previous owner was dealing with the same issue.

 

The easy solution was to install the anti dieseling solenoid which is wired to constant ignition source. When the solenoid retracts the throttle blades close fully without ignition.

 

On a warm start I just rest my foot on the accelerator and crank, and it fires up no issues. Resting my foot is enough to allow the solenoid to extend.

 

This might be a silly question....on a cold start will I have to rest my foot on the accelerator while cranking (to actuate the solenoid)? Or can I pump a couple of times, take my foot away and crank resulting in fast idle? I am thinking my foot has to always be resting on the accelerator regardless of cold or warm start.

 

I might be overthinking this.

 

Thankyou

It's been my experience with my anti-dieseling solenoid (which I use as a a/c compressor idle bump up solenoid) that it isn't strong enough to actually move the throttle linkage but is strong enough to hold it open once actuated.

So you turn the key on and pump the throttle to actuate the choke, and that also lets the solenoid pop out to where it should be.

I agree wid Gary on this one...turn key on, then pump the throttle to set the solenoid(and the choke).

There are actually two different designs on these solenoids, and they both have different functions, design-wise. One is used to kick the throttle up with A/C engagement, and the other is more intended to be the anti-diesel, or throttle stop function. The anti-diesel solenoid's function is to hold open the throttle blades slightly once extended, so the throttle blades do not completely close. This is a result of Gov'ment emissions requirements. Emissions go sky high if/when the throttle is allowed to completely closed on deceleration. Holding the throttle open slightly keeps the emissions within the required limits. Of course...an open throttle tends to promote dieseling on a hot engine when the key is turned off, so it(the solenoid) looses power with the key off, returning the throttle blades to almost completely closed.

The other type solenoid, known as a "kicker", is designed to actually raise the engine rpm as the A/C is engaged, so this requires a solenoid capable of actually moving the throttle linkage....which most are not strong enough to do anymore. Seems the only type of solenoid available today is the weaker, anti-sneezle solenoid....which will require you to hold the throttle open a smidge after the key is turned on for it to hold the linkage at the pre-set rpm range.

While we're at it, if the choke is functioning properly, it should set the throttle on "high idle" the first time you press the pedal anyway. After that, the solenoid will have the idle speed duty.

 

The Holley Solenoid is not capable of pushing the throttle just holding it from my reading.

 

As long as power is on, then the solenoid tries to actuate, as F4Gary mentioned power on and setting fast idle should actuate the solenoid and I can crank with my foot off the accelerator.

 

With the electric choke, I am guessing that is running off the accessory circuit? i.e. as long as the key is in the ignition it runs current to the electric choke to keep it open.

73shark said: I'd recommend measuring it with a VOM and not take a chance. If you don't have one, Harbor Freight has coupons for them periodically for free with another purchase. No minimum on the other purchase either.