Air Conditioning Advice Needed

[Sad Sack]

Hello All,
I believe this is my first post asking the forum for thoughts and I'm not bad mechanically, but A/C is not something I excel at.
So...went to take the truck out the other day, started the truck, heard a quick slight belt like squeal but it went away almost immediately. So I took the truck for a drive, and due to it being really hot (97*), I went to use the A/C for the first time in about a year or so when all worked really well. When I switched the system on, air was just slightly cool not cold like it originally was when system was replaced / converted with the help of a buddy, to R134 with new compressor, accumulator, and orifice tube, my truck stalled when coming to a stop - idling condition. The truck wouldn't restart after placing in park. Switched off the A/C and truck started right up. Switched the A/C back on, same thing, stalled, switched off the A/C and truck started right up and I went about going to my destination without any issues with the A/C system switched off and vent windows employed. Haven't had time to troubleshoot yet and was seeing if I could get directions / suggestions on where to start troubleshooting. Suspicions point me to a compressor issue but that is only an unfounded hunch as of now because of the momentary belt squeal I experienced at the initial startup. A/C is very foreign to me so be gentle in suggestions and no picking on my anatomy or suggesting I do physical things that are impossible to perform. Going to engage a friend later next week who is fairly good with vehicle A/C to look at it, but till then I thought I'd post and just see what comes my way, thank you all, have a safe and happy 4th of July!

 

[gmbellew]

Sounds like maybe the compressor is locked up and when the clutch engages it bogs down the engine?

 

[legopnuematic]

When you attempted to restart with the ac still on was it a crank, no start or no crank, no start?

 

[Sad Sack]

When you attempted to restart with the ac still on was it a crank, no start or no crank, no start?

Cranked but no start.

 

[Sad Sack]

Sounds like maybe the compressor is locked up and when the clutch engages it bogs down the engine?

That's the direction I was leaning to...but guesses have burned me before.

 

[bucket]

I would definitely discontinue use until you can get gauges on it and have a helper with you to diagnose it better.

IF the compressor is locking up, you don't want it sending anymore trash through the system than it already has.

Try rotating the compressor clutch by hand. You should be able to rotate it without much issue. If it doesn't want to turn, you can skip a lot of the diagnostic process and evacuate the system. Then crack the system open and pull the orifice tube for inspection.

 

[legopnuematic]

Ok so a crank, no start situation, almost sounds like you might be losing ignition? Just a SWAG, I can’t recall, do these trucks immediately energize the clutch or is it bypassed while cranking?

If the compressor was locking up I’d expect a labored crank or potentially not even cranking. I know on smaller 4cyl engines that a locked up compressor can make it appear the engine seized up. (Anecdote below*)

Two easy things to try is unplug the compressor, then try starting the truck with the A/C on and try switching it on while running and see if the problem continues. If it continues with the compressor unplugged, that would suggest the issue lies in the harness or something up stream, if it starts and doesn’t stall then the compressor looks more suspect.

Then I’d pull a plug wire off and check for spark while cranking with the AC on and see what you have there.

I wouldn’t be surprised if it was the compressor/something in the system, but easy enuff’ to do the electrical checks just to rule them out.

*A friend of mine was down in Texas for a work study program in the summer a few years ago and had his 97 Civic, cruising on the highway and said it bogged down, heard a clunk and saw something depart from underneath, and the AC quit. What broke free and departed was the front of the clutch and pulley for the compressor.

 

[Sad Sack]

I would definitely discontinue use until you can get gauges on it and have a helper with you to diagnose it better.

IF the compressor is locking up, you don't want it sending anymore trash through the system than it already has.

Try rotating the compressor clutch by hand. You should be able to rotate it without much issue. If it doesn't want to turn, you can skip a lot of the diagnostic process and evacuate the system. Then crack the system open and pull the orifice tube for inspection.

Good advice!

 

[Sad Sack]

Ok so a crank, no start situation, almost sounds like you might be losing ignition? Just a SWAG, I can’t recall, do these trucks immediately energize the clutch or is it bypassed while cranking?

If the compressor was locking up I’d expect a labored crank or potentially not even cranking. I know on smaller 4cyl engines that a locked up compressor can make it appear the engine seized up. (Anecdote below*)

Two easy things to try is unplug the compressor, then try starting the truck with the A/C on and try switching it on while running and see if the problem continues. If it continues with the compressor unplugged, that would suggest the issue lies in the harness or something up stream, if it starts and doesn’t stall then the compressor looks more suspect.

Then I’d pull a plug wire off and check for spark while cranking with the AC on and see what you have there.

I wouldn’t be surprised if it was the compressor/something in the system, but easy enuff’ to do the electrical checks just to rule them out.

*A friend of mine was down in Texas for a work study program in the summer a few years ago and had is 97 Civic, cruising on the highway and said it bogged down, head a clunk and saw something depart from underneath, and the AC quit. What broke free and departed was the front of the clutch and pulley for the compressor.

Thank you, appreciate your input, definitely got some things to look at...

 

[bucket]

@legopnuematic IIRC the clutch will be engaged during cranking. But I'm not positive on that.

 

[Ricko1966]

I had a wire on a harness at work on a Pontiac version of a Cavalier. It would die like some one shut it off turns out a wire had rubbed a bare spot and would kill the engine when the wire would ground out on ICRC the compressor clutch a front bracket? ICRC inspect the wires going to and surrounding the compressor pull the wires off the compressor see if the problem goes away. Reroute them and reconnect them did the problem stay gone?