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Discussion Starter #1
My A/C is driving me bonkers. I changed the compressor, accumulator, and orifice tube during my 4v swap. It has been evacuated, held vacuum for 2 hours and refilled with 34oz of refrigerant and the proper amount of oil. It blew cold all day for the first day. Then it didn't work after a wot run for about 2 days, then this morning it worked again. Drove it to the bank and it stopped working. Hooked it up to my machine at work, pulled 34oz out damn.... Vacuumed it again, recharged it again, no compressor engagement. :mad: bypassed the low pressure switch, no compressor engagement, swapped the head unit with my 95, no change, swapped it back, changed the ccrm with a spare that Supergordo had from his 94 which he said worked, no change.

HELP!!!!!

Where do I check next? It's creeping into the tripple digits and I can't handle it with my medical condition.

Thank you all,
Chris
 

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Discussion Starter #2
More headache.

Bypassed the low pressure switch, unplugged the ac clutch started the car with the ac on max, fan on high, no volts at either pin

Turned the car off, plugged the ac clutch back in, fired it up, compressor engaged!? WTF? Removed jumper wire, reinstalled low pressure switch, kept running!?

Turned ac off, compressor disengaged
Turned ac on, compressor engaged

Grrrr. Turned car off. Restarted car ac works normally...
For now....

What do I check now? The wiring to the clutch? Since now it's working again :rolleyes: for the moment.
 

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As my memory serves there is a high pressure switch as well. And as it serves the high pressure switch is what cuts the a\c off at high rpm. And it works the same as the low as it will cut power to the compressor and cause a no run condition. So you may try jumping it if it stops working again.
 

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I'll check the manual, but seems to me the Gen2s also have the WOT relay, like my 91 does - and if that starts to fail, you'll get some of the same symptoms.

Also, check the clutch air gap ... just in case.

RwP
 

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Discussion Starter #5
where is the location of the wot relay on a 97? Is that part of the CCRM? Which two wires, what colors should I bypass to test the high pressure switch?
 

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Discussion Starter #6
How can I test the ccrm?

How which wires do I bypass for the high pressure switch?
 

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If you can repeat the failure the first thing I would check is power coming into the low pressure switch with a test light and not a DVM. That will tell you if you are getting power and current from the control unit. Do you have SATC or manual controls?

If you get a good light there and the other side of the low pressure switch (should be a red/white wire) then follow that wire to the high pressure switch. Check with the test light the other side (should be pink/lt blue).

If good move on the CCRM if you have a good light on the other side (should be black/yellow) you should be getting power to the A/C clutch. If it doesn't engage it could be the clutch gap which could be too big.

If you use a DVM you will end up chasing your tail - ask me how I know.
 

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Discussion Starter #8
Well diagnostic is done.... bad clutch winding... on my new ac compressor assembly. 0.55 ohms of resistance through the winding. My two old worn out factory compressors which were making noise (bad bearing on one, bad seals in the other) both have winding measuring 0.006 ohms. Is it possible to change the winding from my old one onto my new aftermarket one? Time will tell. In the mean time, rockauto is about to get screamed at again.
 

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Well diagnostic is done.... bad clutch winding... on my new ac compressor assembly. 0.55 ohms of resistance through the winding. My two old worn out factory compressors which were making noise (bad bearing on one, bad seals in the other) both have winding measuring 0.006 ohms. Is it possible to change the winding from my old one onto my new aftermarket one? Time will tell. In the mean time, rockauto is about to get screamed at again.
Before you scream too much - a .006 ohm winding, with 12 volts, will pull 2,000 amps (!!!). .55 ohms pulls more like 22A, a more reasonable number.

I'd check the air gap first.

RwP
 

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Might be a dumb question but you said no volts to the compressor at one point then replugged it and it worked... Does the connector have any corrosion or have the spade style terminals spead open to much. Sounds like a switch or a short.
 

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Discussion Starter #11
I initially thought that there was no voltage to the compressor clutch coil. It turned out I didn't back probe the wire enough, my multimeter leads didn't reach the spades. I t-pinned the connector and have voltage.
 

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For the future reader, a typical AC clutch coil will read two to three ohms and draw from 5 to 8 amps. Check the fuse rating and look up ohms law.

I recently had a GM clutch coil that shorted when hot and blew fuse on the second or third cycle. I diagnosed it in my head right away but dithered around a lot because it's such a PITA to change. Ended up just buying a whole used compressor and putting it on.

Btw: The WOT idea was a good one. Saw that happen long time ago when I had a bad TPS. Of course that presents other symptoms too
 

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Discussion Starter #13
The a/c diag will continue upon reinstallation of the engine. The drivetrain is currently being removed for a new trans.
 

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with just some basic tools you could move the coils from one of your other compressors over to this one. Not too bad to do, I have done it several times on my 94
 

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The a/c diag will continue upon reinstallation of the engine. The drivetrain is currently being removed for a new trans.
A new trans you say... Huh I thought that hardly ever happened? :rolleyes:
 

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A new trans you say... Huh I thought that hardly ever happened? :rolleyes:
Says who? It's a modified 4v 4.6 with a stock 97 trans with 138,000 miles on it with a fresh jmod, new high stall marauder converter, and the roller clutch let go. No need to pour salt and lemon juice in the wound. I only had 2,000 miles on my new setup when it let go. Now the car was professionally broken into I'm paranoid someone is trying to steal it. A/C will get fixed later. Thanks for negatively contributing to my A/C thread.
 

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Says who? It's a modified 4v 4.6 with a stock 97 trans with 138,000 miles on it with a fresh jmod, new high stall marauder converter, and the roller clutch let go. No need to pour salt and lemon juice in the wound. I only had 2,000 miles on my new setup when it let go. Now the car was professionally broken into I'm paranoid someone is trying to steal it. A/C will get fixed later. Thanks for negatively contributing to my A/C thread.
It was a joke man I've replaced my trans 3 times, our transmissions in stock form especially the early ones aren't exactly bullet proof... add more power to the situation and it just gets worse. And I got ya beat on the AC mine doesn't work either and I need a new compressor (leaking) and condensor (clogged solid). Actually I had a 97 mark VIII trans in mine at one point, liked the shifting much better than the stock 94.
 
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