Spider 2000 EFI A/C idle advance mechanism

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bjbrown
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Spider 2000 EFI A/C idle advance mechanism

Post by bjbrown » Thu Jul 12, 2018 7:35 pm

The factory shop manual for fuel injected spiders shows a diagram of the injection system that includes mention of an "idle step-up electrovalve" mechanism for the A/C system. This mechanism has an electovalve and tubing parallel to the Auxiliary Air Regulator valve which also steps up the idle, but just when the car is first started.

ImageAC Idle Step Up Electrovalve Diagram by Bob Brown, on Flickr

I found an extra electrovalve from my 1972 Fiat Spider 850 in my box 'o spares that I thought would work. Its inside diameter is about 3/16" so it's a bit smaller than the hose/valve for the Aux Air Reg Valve. So, I disconnected the hose from the intake plenum and attached a hose to the electrovalve to see if it was sufficient. Running the engine fully warm, I engaged (opened) the electrovalve, but nothing happened. Now, the end of the electrovalve was open to atmosphere (instead of drawing air from the main air hose after the air filter and air flow meter but before the throttle plate and intake plenum as described in the diagram). Was my test setup adequate to determine if the electrovalve was of enough flow to effect the idle step-up I need, or do I need to tap into the air flow per the diagram?
Boise, Idaho
1972 Fiat Spider 850
1980 Fiat Spider 2000
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atruscott
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by atruscott » Thu Jul 12, 2018 10:14 pm

Did the valve actually open? Shouldn’t matter where the air is drawing from.
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bjbrown
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by bjbrown » Thu Jul 12, 2018 10:17 pm

Yes, the valve opened just fine. It just didn’t seem to alter the idle at all...
Boise, Idaho
1972 Fiat Spider 850
1980 Fiat Spider 2000
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bjbrown
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by bjbrown » Thu Jul 12, 2018 10:21 pm

So, does anyone have a Fiat Spider with A/C that actually has the electrovalve for “idle step up?” If so, would you reply with a photo? I’m curious what is used, what size it is, how the inlet tube is configured and where the electrovalve is mounted...
Boise, Idaho
1972 Fiat Spider 850
1980 Fiat Spider 2000
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bartigue
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by bartigue » Thu Jul 12, 2018 11:03 pm

I’ve never seen one where they installed it!
-----------------------------------------------------------
Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
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bjbrown
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by bjbrown » Thu Jul 12, 2018 11:05 pm

Yeah, I had a NOS (dealer) kit and it wasn’t included or even mentioned...
Boise, Idaho
1972 Fiat Spider 850
1980 Fiat Spider 2000
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kmead
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by kmead » Sun Jul 15, 2018 6:22 pm

What you have done is added unmetered air. This is leaning the combustion mixture.

You need to run the plumbing just as the factory did so that it is drawing air through the Air Fuel Meter and the AFM will meter more fuel raising the idle speed, effectively as if the throttle was opened by the amount of air that is bypassing the throttle plate with your valve.
1969 850 Sport Coupe
1970 124 Sport Coupe
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mikehynes
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by mikehynes » Mon Jul 16, 2018 10:49 am

bjbrown wrote:
Thu Jul 12, 2018 10:17 pm
Yes, the valve opened just fine. It just didn’t seem to alter the idle at all...
The X1/9 did have factory air, and did mount the EFI A/C idle advance mechanism as shown above. I pulled all of the stuff off of an AC equipped parts car and and installed in all on a non AC car, thinking that I could have a switchable hi idle function. It didn't work. Didn't do anything. As far as I know it SHOULD have worked, but it didn't change anything that I could see. Extra air into the intake manifold should be just like opening the throttle blades a little bit right?
Two '80 124 Spiders
Lots of X1/9s
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by kmead » Mon Jul 16, 2018 10:29 pm

Yes as long as the AFM sees the air, it should act like the throttle plate is opened slightly.

I don’t know if the X had the same diameter valve as the 124, the 850 air valve I am pretty certain is a smaller diameter opening than my 87 AC X’s valve.
1969 850 Sport Coupe
1970 124 Sport Coupe
1985 X1/9, ugly but fun to drive. Olive trees are hell on paint and interiors apparently. Who knew?
1987 X1/9 slowly coming back
And a few appliances for day to day
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Re: Spider 2000 EFI A/C idle advance mechanism

Post by bjbrown » Tue Jul 17, 2018 11:56 am

Mikehynes, would you still have the parts? Would you be interested in selling them? Perhaps a photo especially of the electrovalve and the pipe on the intake side of the circuit?

Knead, a photo of your setup??
Boise, Idaho
1972 Fiat Spider 850
1980 Fiat Spider 2000
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