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Idle Speedup Solonoid Working Backwards

Started by Scott Halver, April 02, 2016, 08:40:50 PM

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Scott Halver

Hello,  (Previous Post 2015, 1960 Cadillac w/ tri-power, idle speedup solenoid NOT working)
So, I managed to get my idle speedup solenoid rebuild by a " CA company".    I hooked everything up (vacuum and electric) and it works backwards......  the plunger goes out when the car is turned off and then the plunger moves in or off the idle cam when the car is started ??   (almost like a anti-dieseling solenoid)    The plunger is in the same position when the car is turned-off as it was when I first installed the idle speedup solenoid.

I have electric/power when the ac is turned-on..... but really no change, only movement is when the car is started or turned off..........vacuum moves the plunger.    I could not tell which wire was for ground and which was for ground when hooking up (new wires were both black, no visible difference).   I tried reversing the wires but no change.

Could something be reversed inside or the "valve" stuck (elec magnet moves a rod/valve on my solenoid to change where the vacuum goes, no ball) ?

Any thoughts are appreciated.   SHalver CLC #24920
1960 Eldorado Seville, Grandfather Bought New
1970 Corvette Convertible 350/350

John Washburn CLC 1067 Sadly deceased.

Scott,

Take a look at the last two months of the Self Starter. Two articles on this subject by me.

One error - The unit only engages when the AC is on and the car is not in gear, unless you modify it like I did.

If you have any questions after looking at the articles drop me a PM.

John Washburn
John Washburn
CLC #1067
1937 LaSalle Coupe
1938 6519F Series Imperial Sedan
1949 62 Series 4 Door
1949 60 Special Fleetwood
1953 Coupe DeVille
1956 Coupe DeVille
1992 Eldorado Touring Coupe America Cup Series

Scott Halver

John,
Thank you for responding ......   grounds through the starter safety neutral switch !!    I read your two articles and I knew that was why we had two leads to the solenoid instead of just grounding it at the engine......  but I went BRAIN DEAD.     I think you have to stand on your head to understand this one (or Merlot), when energized (ac on) the vacuum ceases to "hold the rod back" and it moves forward, then as you lose electricity (turn off ac) the vacuum pulls the rod back and the engine slows up.   I just assumed that the vacuum applied should move the rod out and speed-up the engine-  wrong.   Test Performed:   with the engine running and ac on, I grounded the correct lead and rod moved, engine speed increased.   I had to play with the adjustment/rod to get the "right increase" in rpms.

Note:   This solenoid works slightly opposite an anti-dieseling solenoid....... as you turn off the engine the throttle is likely to get pushed open slightly more, just the opposite of what you would want if the car had a tendency to diesel.   

My starter safety switch is not grounding the solenoid and is probably a simple fix, wire off or something.   However, I am thinking of just grounding the wire and then the engine would speed up slightly any time the ac is turned on..........   any real reason not to ?     don't have it set to speed up the engine so much that it would run over anyone.

Thanks, SHalver CLC #24920
1960 Eldorado Seville, Grandfather Bought New
1970 Corvette Convertible 350/350

John Washburn CLC 1067 Sadly deceased.

Scott,

On my 56 the fast idle turns on when I turn the AC on. I have had this modification on the 56 since the early 80's and have not had a problem. Great for stop and go traffic and especially parades.

Also check to see if you have a six blade fan that also helps it was a change listed in the Cadillac Serviceman for 1956 for AC cars.

Glad you figured it out.

the Johnny
John Washburn
CLC #1067
1937 LaSalle Coupe
1938 6519F Series Imperial Sedan
1949 62 Series 4 Door
1949 60 Special Fleetwood
1953 Coupe DeVille
1956 Coupe DeVille
1992 Eldorado Touring Coupe America Cup Series

76eldo

I have worked on a 60 with AC, with the single 4 barrel.

With the AC on, the solenoid engages and bumps up the idle.  In Park, in Drive, whatever.  Are you sure that the neutral safety switch is in the mix?

What good does it do only in Park or neutral?  When you are at a light with your foot on the brake with the AC on, that's when you need a few more RPM's.  ??

I am confused by this, and I'll be at this point with one of my cars hopefully in a few months.

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

J. Gomez

Folks,

The A/C fast idle solenoid “ONLY” works when the shift lever/NSS is set on “P” or “N” on all of the 195X- 1962 with AC.

The solenoid itself does not care which side is “+” or “-“, any connection to it should work.

The positive side for it is straight forward same path as the compressor clutch solenoid.  However the ground is a bit tricky, it is feed from the “starter solenoid” via the “S” connection.

The starter solenoid “hold” coil is grounded, so this resistance ground is the one that is used for the fast idle solenoid to operate. Since the “S” wire is connected to the NSS to operate the starter and the starter can “ONLY” be energized when the shift lever/NSS is in “P” or “N”.

On the Rochester one, the fast idle solenoid “opens/closes” the vacuum valve, when not-energized the valve is closed and vacuum pulls the rod inwards. Once energized the valve opens closing the vacuum source, the spring tension forces the rod outwards forcing the carb to rev the engine.

I believe the Carter WCFB functions the same but please refer to Johnny’s CLC articles.

Hope this help..!
J. Gomez
CLC #23082

Scott Halver

Good Responses,
So am I okay grounding the solenoid to the block ?    ...so that it comes "on" whenever the ac is on.   You mentioned a resistor in the grounding at the starter, makes me think if you "over" ground the circuit the magnet might get too much voltage/amperage and burn up ?      If I remember right, the hot wire for the compressor and the idle speedup solenoid are from the same source, probably a little more amperage to pull the compressor.

Thanks for the help, SHalver CLC #24920
1960 Eldorado Seville, Grandfather Bought New
1970 Corvette Convertible 350/350

J. Gomez

#7
Quote from: Scott Halver on April 03, 2016, 09:21:51 PM
So am I okay grounding the solenoid to the block ?    ...so that it comes "on" whenever the ac is on.   

Scott,

The “ground” source for the solenoid would be coming from the NSS “Purple/Violet” wire. It may be a pig-tail to extend the connection over to it as the main “Purple/Violet” goes to the ignition switch.

I would not recommend in wiring it directly to a ground source as it will be working on any position of the shifter.

You can see the path I was referring (light blue) on the attached drawing.

Quote from: Scott Halver on April 03, 2016, 09:21:51 PM
Good Responses,
You mentioned a resistor in the grounding at the starter, makes me think if you "over" ground the circuit the magnet might get too much voltage/amperage and burn up ?     

The resistance is from the starter solenoid "hold" coil" and since the fast idle solenoid coil may stay energized for some long periods it serves as a protection for the smaller coil on the fast idle solenoid. So yes, you are correct on your statement..!

Second attachment shows the "holding coil" to ground under the violet bar for reference.



Hope this help..!
J. Gomez
CLC #23082

Scott Halver

Hello J Gomez
Yes, your response helps and it sounds like I should NOT just ground the idle speedup solenoid at the engine block (unless maybe I used a resistor).   I'm not as concerned with the fast idle occurring while the car is in gear.    I don't have it adjusted up so much that it makes a huge difference, run over someone etc.    I need to look at your wiring diagram some more and then go under the dash to see where I'm lacking contact for the ground.   I put a "new" old starter safety neutral switch in last year to correct/facilitate the parking brake release (vacuum) and I know that the car will not start if in gear..........   so I'm not sure what my problem is but I will run it down.

Thank you for helping me !!  SHalver CLC #24920
1960 Eldorado Seville, Grandfather Bought New
1970 Corvette Convertible 350/350

John Washburn CLC 1067 Sadly deceased.

Scott,

Jose is spot on. I just did it on the 56 which is wired somewhat different.

The Johnny

John Washburn
CLC #1067
1937 LaSalle Coupe
1938 6519F Series Imperial Sedan
1949 62 Series 4 Door
1949 60 Special Fleetwood
1953 Coupe DeVille
1956 Coupe DeVille
1992 Eldorado Touring Coupe America Cup Series