1973 Electrical problems
Thread Starter
5th Gear
Joined: May 2013
Posts: 5
Likes: 0
From: Abu Dhabi
1973 Electrical problems
I replaced my 1973 L48 engine with 350 Goodwrench 5.7L 260hp engine. Edelbrock intake and performer Carb with electric chock. HEI GM performance timing and electrical fans. Alternator replaced with 110 amp. If A/C is on, power cut when not moving or speed reduced to very low speed. However it doesn't while on highway. Btw I have ACDelco 78 battery. What could be the problem? Please help
Last edited by Mak73Corvette; Sep 26, 2014 at 09:24 AM. Reason: Adding info
Thread Starter
5th Gear
Joined: May 2013
Posts: 5
Likes: 0
From: Abu Dhabi
Battery checked
I checked the battery and alternator, they are perfect and stable. Battery is full on 14 when idle and 2500 rpm. Alternator is working fine too.
Last edited by Mak73Corvette; Sep 27, 2014 at 12:31 PM. Reason: Spelling
Le Mans Master
Joined: Oct 2006
Posts: 6,842
Likes: 285
From: Palmdale CA
What "power" is being cut? Electrical? Engine? If it's engine power and you say that on the highway, it's fine, but at low RPM, it dies, but only with the AC on, then I'd check a couple of things.
First, if you have a Quadrajet carb, I believe there was a linkage that bumped up the idle of the engine, when the AC was turned on, to compensate for the physical load the AC put on the motor.
Secondly, I'd check the AC compressor itself to make sure it's not frozen up, or putting a heavier load than normal on the engine.
First, if you have a Quadrajet carb, I believe there was a linkage that bumped up the idle of the engine, when the AC was turned on, to compensate for the physical load the AC put on the motor.
Secondly, I'd check the AC compressor itself to make sure it's not frozen up, or putting a heavier load than normal on the engine.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
It is NOT a linkage that increases the idle when the Air Conditioning is being used at IDLE....BUT rather an actuator solenoid that will actually push out and hold the throttle linkage to about 100 RPM's higher than normal. NOW...this actuator solenoid will not push back the throttle at idle...but when you turn on your A/C and press on the gas pedal...the actuator solenoid will come out and stop...and when you let off the gas pedal...it will NOT allow to throttle linkage to go back to the base idle setting. So...this actuator solenoid is adjustable.
Also...it is wise to let the engine warm up a little bit before you put on the A/C when the engine is cold. But if 'things' are set correctly...you should be on fast idle when it is cranked cold. which is higher than your curb idle setting.
DUB
Also...it is wise to let the engine warm up a little bit before you put on the A/C when the engine is cold. But if 'things' are set correctly...you should be on fast idle when it is cranked cold. which is higher than your curb idle setting.
DUB
Burning Brakes
Joined: Sep 2005
Posts: 1,050
Likes: 205
From: Lewes Delaware
Not true on a 73. The solenoid on the Quadrajet is "extended or actuated" when the ignition is "on" and used to prevent "dieseling" when the engine is shut off. There is nothing on the engine to raise its RPM's when the AC is turned on.
Fran
Fran
Last edited by Blue73Shark; Sep 27, 2014 at 07:53 PM. Reason: Redo explanation
Race Director
Joined: Apr 2009
Posts: 19,294
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From: Charlotte NC
Thanks...It did not register in my head it was a 1973...I was thinking of the later years, which do use the power from the A/C to get the actuator to move outwards and increase the idle. GM got smart and did another improvement...as they seem to do. which gets me confused sometimes when I am dealing with a year model that is different. WAY too many things in my head at times.Thanks again for the correct clarification.
DUB
Last edited by DUB; Sep 28, 2014 at 07:07 PM.
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Thread Starter
5th Gear
Joined: May 2013
Posts: 5
Likes: 0
From: Abu Dhabi
1973 with later engine.
I would like to thank you for all the relies and help. Please keep in mind that my Vette Engine is not stock.
I had my carburetor tuned well. I was advised to replace my factory compressor with a Japanese Land Cruiser one or I have to fix (actuator solenoid) on the carb to make RPM high when A/C is on.
I had my carburetor tuned well. I was advised to replace my factory compressor with a Japanese Land Cruiser one or I have to fix (actuator solenoid) on the carb to make RPM high when A/C is on.
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
Check your wiring. Did you replace a points distributor with an electronic? Check starter wiring. Wiper wiring (grounding) can be crossed. Look and feel for "hot" wiring or components. I had a grounding issue with my windshield wiper that drained my battery in a day.
Good luck!
Good luck!
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
If you have the actuator solenoid on the carb now...I would get it working. And wire it to work when you turn on your A/C.
Do you have a fast idle when you crank the engine when COLD???? What is your RPM's as fast idle???
And...I assume that your choke allows you to let it run fora few minutes and tap the gas pedal and it idles down to curb idle....correct????
DUB
Do you have a fast idle when you crank the engine when COLD???? What is your RPM's as fast idle???
And...I assume that your choke allows you to let it run fora few minutes and tap the gas pedal and it idles down to curb idle....correct????
DUB