Anyone have their anti-dieseling installed?

[71CHEVYSHORTBED402]

I've never seen one connected - it be nice to see one, what the connections are, and what year.....Just curious is all.

I believe my 71 had one with the solenoid installed under the dash panel. I think something else ran to the compressor, though couldn't tell you the configuration.

Thanks.

[RustyPile]

The solenoid, whether it's an anti-dieseling application for closing the throttle, or a step-up application for maintaining proper idle speed when A/C compressor is engaged, the solenoid is always mounted on or near carburetor.. Not under the dash.

Refer to this thread.. The OP posted pictures of what, where, and when it's mounted. Refer to a proper wiring diagram for the proper wiring..

https://67-72chevytrucks.com/vboard/...d.php?t=861085

[howzzzit]

Originally Posted by 71CHEVYSHORTBED402

I've never seen one connected - it be nice to see one, what the connections are, and what year.....Just curious is all.

I believe my 71 had one with the solenoid installed under the dash panel. I think something else ran to the compressor, though couldn't tell you the configuration.

Thanks.

Note it has retracted with ignition off. Turn on key it pushes against the throttle. With truck running you turn bolt cw to reduce idle speed and ccw to increase speed. My original a/c is still functional. Don't ask where the wire goes. Crap picture sideways, but you can turn your monitor over.

[Steeveedee]

Originally Posted by 71CHEVYSHORTBED402

I've never seen one connected - it be nice to see one, what the connections are, and what year.....Just curious is all.

I believe my 71 had one with the solenoid installed under the dash panel. I think something else ran to the compressor, though couldn't tell you the configuration.

Thanks.

Pretty sure it's the kickdown switch under the dash? It went from being in the intake manifold to under the dash, in '71. I think.

[60case]

I have a 72 blazer 350 no a/c The anti dieseling solenoid wire goes inside to the fuse box plugs into ing unfused spot

[Rich72C10]

Here is some information on the tread I started. Mine is working as it should be, from the factory after I got another NOS Solenoid.

Hope you find it useful.

[71CHEVYSHORTBED402]

Originally Posted by Rich72C10

Here is some information on the tread I started. Mine is working as it should be, from the factory after I got another NOS Solenoid.

Hope you find it useful.

If you intended to link to something it's not in your post.

Wow, you guys mean to tell me the anti desieling in my 71 402 ac was the idle stop all along...

Wow, well I pulled the idle stop with a restoration, wasn't operational anyway. I think it may have deseiled a bit one time after every thing rebuilt.... I imagine it helps to turn the ac off before turning the key off.. I don't have my notes handy, but there were a few wires running to the solenoid at the carb. I'll update when I get home. May have been a 71 config. Mixed in with tcs?

I thought a solenoid may have been under the dash.. seems there's a fixed nut in the dash near the lighter, ill check that too. There was also a wire harness, disconnected inside the cab, i think 12 gage yellow, light blue and or. I thought that went to the mystery if ever solenoid at the dash. I know the kick down is something else completely, my 71 has one. Thank you.

[Steeveedee]

I don't remember when this started, but there was for awhile a solenoid that had vacuum to it that kept the A/C clutch engaged for some amount of time after the engine was turned off, to stop it as well. I had that system on an '85 Pontiac Parisienne wagon I had. After the vacuum was reduced, the solenoid de-energized. The bleed hole got clogged, and the A/C clutch stayed engaged, causing a dead battery. That was fun tracing down.

[Rich72C10]

Sorry about that, here it is 72 C10 QJet "Solenoid"

[SRU1436]

Here is mine while still on the truck, off the carburetor during the carb rebuild, and temporarily on the carb while on the bench. My truck is an all original 72 C10 Cheyenne, 350/350 no AC. I haven’t tested it to see if it works. My hope this weekend it’s to get the carb back on and running.

[71CHEVYSHORTBED402]

Originally Posted by Rich72C10

Sorry about that, here it is 72 C10 QJet "Solenoid"

Well that sure was educational, thank you. With that and more, yeah, Idle Stop and Anti-dieseling are the same things, though perhaps one or the other suit certain applications. Mine had the Idle Stop, and it's just as described in post 3 of that thread.

I mistakenly mentioned I had a solenoid under my dash. That's for the anti-dieseling Relay. I never saw mine installed, though the truck still had the wiring for it. The relay installs per the image below.

Anyone know what years had TCS? Mine were mounted on the exterior firewall, I think some have the relay and/or delay inside the cab.

FWW...for my 1971 400TH with A/C

I believe the relay was wired as....
• 12 AWG orange - this wire ran to the blower relay.
• 12 AWG pink - this wire connected to fuse panel’s IGN. UNFUSED terminal.
• 14 AWG dark green - this wire connected to the A/C switch.

I believe my TCS and Idle Stop were wired like this...

The TCS assembled with a relay unit, and a delay unit mounted to the firewall. The LH unit is the smaller of the two, and may be the RELAY ASM CONT SW. The RH unit may be the RLY ASM TRANS CONT SW DELAY. The LH unit’s tab is its top. The RH unit’s terminals are its bottom.

• A 24 AWG brown/white striped wire connects from the firewall block’s RH side to a connector with two brown wires. The shorter brown wire plugs onto the RH unit’s bottom terminal. The longer wire runs to the ISS.

• A 20 AWG black wire plugs onto the RH unit’s bottom terminal with the brown wire stated above. The black wire plugs onto the transmission’s pass-through terminal with a boot connector, which includes the transmission kickdown switch wire.

• Two 18 AWG dark blue wires plug onto the RH unit’s top terminal. The shorter dark blue wire plugs onto the LH unit’s bottom terminal. The longer one runs to the ISS.

• A 24 AWG brown/white striped wire plugs onto the LH unit’s top terminal. This wire runs to the ISS. The plug included a dark green wire, which had been cut. Perhaps this wire connected to the TCS assembly’s temperature sender.

[Steeveedee]

Depending on application, TCS was used from '70 - '75, inclusive. My 3/4T truck for example, did not have it. Without digging further, I'd expect that 3/4T and bigger trucks did not have it. This information is derived from the Chilton's repair and tune-up guide for '70 - '80 Chevrolet and GMC trucks.

[71CHEVYSHORTBED402]

Originally Posted by Steeveedee

Depending on application, TCS was used from '70 - '75, inclusive. My 3/4T truck for example, did not have it. Without digging further, I'd expect that 3/4T and bigger trucks did not have it. This information is derived from the Chilton's repair and tune-up guide for '70 - '80 Chevrolet and GMC trucks.

Thanks Steveedee. Come to think of it my 72 C20 didn't have evidence of having it either.

[71CHEVYSHORTBED402]

Here's a good explanation I found for the Anti-Dieseling Relay, that was in my dash....I think they were installed beginning 1971, not to say some 1970 wouldn't have them.

"The anti-dieseling relay energizes the A/C compressor for a few seconds when the ignition key is turned to the off position with the intent being the added drag will prevent dieseling. The blocking relay prevents the blower motor from turning on during this cycle.".

Just a guess without one it's a good idea to shut the A/C off well before the engine is shut off - should do that anyway.

Unless I'm mistaken the anti-dieseling/idle-stop without TCS is operated by a single pink wire. In hindsight I would have installed one, without the TCS of course, though my engine seems to shut off well without one.

This thread has taught me a lot, thank you. Looking through my image files I found this for an anti-dieseling/idle-stop slash with a nasty TCS config..

[Donnie3]

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[Donnie3]

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