a/c idle solenoid install

Stevehose

Stevehose

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To occupy my time while my head is being worked on I installed a solenoid that will bump the idle speed when the a/c compressor cycles on. I was going to use vacuum advance but 61Porsche sent a link from another forum with the electric solenoid.

It's an ES-44 model and cost $25, I fabricated and painted black a bracket for it:
IMG-20121027-00058.jpg


Then I ground down an old linkage ball flat on one side, this mounts in a hole on the accel linkage plate on the block:
IMG-20121027-00057.jpg


Also added a separate ground wire and mounted it to the bracket:
IMG-20121027-00062.jpg


Installed it to the block (there are 2 unused threaded holes on the block perfect for this, I used the lower one and angled it up towards the ball to line up with the action of the throttle:
IMG-20121027-00063.jpg


I grounded it to the oil filter plate and wired the positive behind the firewall insulation and tapped into the a/c compressor wire. Final install is not very noticeable.

The solenoid is adjustable so when I get my engine running I will fine tune the positioning and idle rpm bump. So far it looks like it will work and will update in due course.
 
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My 2800 CS has a kind of fast idle solenoid (electric and vacuum actuated) at the rear of the engine that is designed to hold the carburetors open slightly during deceleration until the rpm drops to a preset number. I used this solenoid to bump the rpm when A/C is on. I don't remember all the specific details since I did it so many years ago. This is what I remember, I installed another A/C relay that is used to turn on the electric fan in front of the radiator. I jumped the input wiring from the original relay to the new one. The output wiring of the new relay was routed to the fast idle solenoid so it would activate the high idle when the A/C was turned on. I adjusted the solenoid to idle at the correct rpm with the A/C on. This has worked well for many years.

I have not used the A/C for a few years now because the freon is low and I ran out off my R-12 supply. I guess I will have to take it to an A/C repair shop that still uses R-12.
 
Was the electric solenoid a success?

Hi Steve, was the electric solenoid a success in adjusting the idle speed when the air conditioner is operating. I am considering your solution and would like to ask you the dimensions of the bracket you made. (save reinventing the wheel). Kind Regards Mark (nice colour)
 
The bracket was made by cutting a piece off some metal stock from a home improvement store (Home Depot). The distance between the bolt hole (which in the pic you can see I drilled) and the 90 degree bend is a hair under 4.25".

The solenoid works, but it is not powerful enough to kick the idle up on it's own (I researched this and it would take a powerful and pricey solenoid to do so), so if the a/c cycles back on at idle you have to blip the throttle a little to set it. Otherwise it holds it steady when a/c is on. I like it.

nice colour said:
Hi Steve, was the electric solenoid a success in adjusting the idle speed when the air conditioner is operating. I am considering your solution and would like to ask you the dimensions of the bracket you made. (save reinventing the wheel). Kind Regards Mark (nice colour)
Click to expand...
 
Update: rewired the solenoid

I had the solenoid wired to the compressor circuit but it was bugging me at a stop light when it would cycle on and off, I had to keep blipping the throttle as noted below. So I thought I'd try wiring it to the fan circuit so it engages anytime the a/c is on whether cycling or not. This solves the problem, and at a stop light it only varies about 100 rpm (1000-900) with no threat of stalling or gagging like before installing the solenoid and no need to manually jack up the idle to compensate for when the compressor kicks in. I wired it to the power-in side of the temperature switch, just check which wire it is by testing with a volt meter and turning on and off the fan switch. I ran the wire up through the spade connector plastic and it compresses in place when installed on the spade.

IMG_1162.JPG
 
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