AC Clutch Cycle
05-18-2012, 09:10 PM
#1
AC Clutch Cycle I am running a Vintage Air GenIV setup in my 69 C10 (Carbed LY6. no ecu control).
The system blows cold, but the compressor cycles on for 10 seconds without fail. Doesn't matter if I am idling or cruising, its like the thing is on a timer. I charged it myself and my pressures with the system filled were about 15psi low and 200 hi, but since the compressor only stays on for 10sec, its hard to say that those are stable numbers. I called Vintage Air and they thought this was related to working on it after dark when its cool outside. I parked the truck outside in the 90deg heat and let it bake. Same issue. Truck is cool inside, but the compressor cycles on for 10sec then off for 20-30 sec. Haven't called Vintage back. I am running the binary switch that Vintage supplied. My efan switch ties into one side of the binary for fan signal. I disconnected this to test and it does not change the compressor cycling.
Getting ready for Power Tour and I am worried about burning up the compressor clutch. Any ideas?
The system blows cold, but the compressor cycles on for 10 seconds without fail. Doesn't matter if I am idling or cruising, its like the thing is on a timer. I charged it myself and my pressures with the system filled were about 15psi low and 200 hi, but since the compressor only stays on for 10sec, its hard to say that those are stable numbers. I called Vintage Air and they thought this was related to working on it after dark when its cool outside. I parked the truck outside in the 90deg heat and let it bake. Same issue. Truck is cool inside, but the compressor cycles on for 10sec then off for 20-30 sec. Haven't called Vintage back. I am running the binary switch that Vintage supplied. My efan switch ties into one side of the binary for fan signal. I disconnected this to test and it does not change the compressor cycling.
Getting ready for Power Tour and I am worried about burning up the compressor clutch. Any ideas?
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05-19-2012, 10:18 AM
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I am running a Vintage Air GenIV setup in my 69 C10 (Carbed LY6. no ecu control).
The system blows cold, but the compressor cycles on for 10 seconds without fail. Doesn't matter if I am idling or cruising, its like the thing is on a timer. I charged it myself and my pressures with the system filled were about 15psi low and 200 hi, but since the compressor only stays on for 10sec, its hard to say that those are stable numbers. I called Vintage Air and they thought this was related to working on it after dark when its cool outside. I parked the truck outside in the 90deg heat and let it bake. Same issue. Truck is cool inside, but the compressor cycles on for 10sec then off for 20-30 sec. Haven't called Vintage back. I am running the binary switch that Vintage supplied. My efan switch ties into one side of the binary for fan signal. I disconnected this to test and it does not change the compressor cycling.
Getting ready for Power Tour and I am worried about burning up the compressor clutch. Any ideas?
The system blows cold, but the compressor cycles on for 10 seconds without fail. Doesn't matter if I am idling or cruising, its like the thing is on a timer. I charged it myself and my pressures with the system filled were about 15psi low and 200 hi, but since the compressor only stays on for 10sec, its hard to say that those are stable numbers. I called Vintage Air and they thought this was related to working on it after dark when its cool outside. I parked the truck outside in the 90deg heat and let it bake. Same issue. Truck is cool inside, but the compressor cycles on for 10sec then off for 20-30 sec. Haven't called Vintage back. I am running the binary switch that Vintage supplied. My efan switch ties into one side of the binary for fan signal. I disconnected this to test and it does not change the compressor cycling.
Getting ready for Power Tour and I am worried about burning up the compressor clutch. Any ideas?
05-22-2012, 09:20 PM
#10
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knowing nothing but what you have listed, low side normal & high side normal but high evaporator temp...
1. Non-condensables in the system, i.e., air, moisture, or both
2. faulty TXV? the expansion valve could be stuck. This would flood the evap with refrigerant and raise the outlet temp. if this were the case I would expect the low side pressure to be elevated.
Back to #1. How did you evacuate the system? Did you use a REAL vacuum pump or one of those POS Harbor Freight pumps?
05-23-2012, 07:24 AM
#11
At this time, they have not offered any ideas. Its my opinion that there is a bad component in the evaporator unit, either the temp probe or the temp probe circuit. We ran the truck and timed the compressor cycle on/off yesterday and it was amazingly consistent. Cycle on 15 sec, cycle off 10sec. Its all computer controlled. I'm thinking its in some sort of "limp" mode due to bad component/signal.
I evacuated it using an electric vacuum pump, not harbor freight. System was on vacuum for about 1hr 15min
I evacuated it using an electric vacuum pump, not harbor freight. System was on vacuum for about 1hr 15min
05-23-2012, 08:35 AM
#13
VA says center vent temp in my current weather should be around 45F. Im around 56F. It cools the truck off and is colder than my 2011. Not only is the constant compressor cycling annoying, Im sure its going to affect the life of the unit. I haven't driven it for more than an hour or so straight. Not sure what might happen on an 8 hr drive.
05-23-2012, 09:26 AM
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At this time, they have not offered any ideas. Its my opinion that there is a bad component in the evaporator unit, either the temp probe or the temp probe circuit. We ran the truck and timed the compressor cycle on/off yesterday and it was amazingly consistent. Cycle on 15 sec, cycle off 10sec. Its all computer controlled. I'm thinking its in some sort of "limp" mode due to bad component/signal.
I evacuated it using an electric vacuum pump, not harbor freight. System was on vacuum for about 1hr 15min
I evacuated it using an electric vacuum pump, not harbor freight. System was on vacuum for about 1hr 15min
05-23-2012, 09:36 AM
#15
I know I can try that, but I was waiting for VA to instruct me to do it. The whole system is new under warranty, don't want to jeopardize that right now.
I talked to them this morning, they are sending out a new ECU. I will have that tomorrow and I will swap it out tomorrow after work. Fingers crossed
I talked to them this morning, they are sending out a new ECU. I will have that tomorrow and I will swap it out tomorrow after work. Fingers crossed
05-23-2012, 05:51 PM
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I know I can try that, but I was waiting for VA to instruct me to do it. The whole system is new under warranty, don't want to jeopardize that right now.
I talked to them this morning, they are sending out a new ECU. I will have that tomorrow and I will swap it out tomorrow after work. Fingers crossed
I talked to them this morning, they are sending out a new ECU. I will have that tomorrow and I will swap it out tomorrow after work. Fingers crossed
05-24-2012, 06:06 PM
#17
ECU did not fix it. I jumpered 12V to the compressor and bypassed the circuit. The system did what its supposed to do. It was an icebox in the truck, just running it at high idle in the driveway for 2 minutes. To my surprise, when I disconnected my jumper and immediately reconnected the VA ciruit, it didn't cycle for quite a while. Compressor was off. What that tells me is that the temp probe is likely reading accurately since it was aware that the evap core was colder than it wanted. What I can't understand is why the temp probe thinks it needs to cut off power to the compressor too soon. I figured that would be an ECU function, but that has been replaced.
05-24-2012, 08:31 PM
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Looks like you are making progress. Have you talked to vintage air to update them on your progress? I don't have any more advice. My speciality is refrigeration (HVAC).
05-24-2012, 08:33 PM
#19
I installed the ECU after work. I left a voicemail for the tech rep who was been helping me out. Im sure I will get a call from him tomorrow AM.
It has to be the temp probe or the wiring. Those are the only components left in the compressor ON circuit that have not been replaced/confirmed good. My worry right now is how serviceable the temp prob is. The evaporator comes as an assembled unit with the probe inside. If the entire evaporator has to come out, thats going to be a big chore for this weekend.
It has to be the temp probe or the wiring. Those are the only components left in the compressor ON circuit that have not been replaced/confirmed good. My worry right now is how serviceable the temp prob is. The evaporator comes as an assembled unit with the probe inside. If the entire evaporator has to come out, thats going to be a big chore for this weekend.
06-07-2012, 09:09 PM
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I installed the ECU after work. I left a voicemail for the tech rep who was been helping me out. Im sure I will get a call from him tomorrow AM.
It has to be the temp probe or the wiring. Those are the only components left in the compressor ON circuit that have not been replaced/confirmed good. My worry right now is how serviceable the temp prob is. The evaporator comes as an assembled unit with the probe inside. If the entire evaporator has to come out, thats going to be a big chore for this weekend.
It has to be the temp probe or the wiring. Those are the only components left in the compressor ON circuit that have not been replaced/confirmed good. My worry right now is how serviceable the temp prob is. The evaporator comes as an assembled unit with the probe inside. If the entire evaporator has to come out, thats going to be a big chore for this weekend.