I have a '92 E-350 SuperClubwagon. The problem I am having, is the AC kicks off prematurely. I understand that it is supposed to kick off at WOT, or at least when the engine is under heavy load. However it seems to kick off under lighter loads, like slight grades (and i mean slight, like 2% and 3% grades), and then resumes to come back on, unless I turn it off then on again. Does somehing need to be adjusted, or what might the problem be here. It started doing this after I had the an AC hose blow out on me, and had to have it fixed. The pressure on the AC charger seems correct, so what might the problem be? Shortly afterwards, the TPS gave out, and I had it to replace it, and I reset the computer. Still, this persists, and it gets unbearable when you have 13 people in a van, driving in the Utah desert with no AC, and in fact, hot air blowing out of the rear vents becuase the system thinks the vehicle is under heavy load. what are some things I can test? I pulled codes from the computer, and the only one that comes up, is a code for a faulty EGR valve sensor, but that should not affect the AC system.

 

I think you need to recheck charge. These have a low pressure cut out. Was this truck converted to 134a? Pressures would be different with the new gas.

 

No, it was not converted. I will check the pressures again. Where is the low pressure port on these things anyway? I can see the high pressure side near the compressor.

 

It is on on the driver's side of the motor tunnel, hard to get to. Mine has the 351

 

if one of the AC lines broke open and the system was not properly repaired, you may have junk/moisture floating around in the system causing problems. you could be low on charge also.

 

WEll, it started doing this immediately after having it repaired. As mentioned above, my TPS went out, which could have temporarily caused problems. The shop that did the repair specializes in AC repair, and they have done good work for us in the past. I'm pretty sure they properly repaired it, as there is no problem with the cooling efficiency.

 

did you check all vacuum hoses? A leak could make sensor think engine under load.

 

No, I didn't check the vacuum. Didn't have any symptoms that might have suggested a vacuum leak. I haven't really driven it much since the TPS was replaced, and generally, it is hard to diagnose A/C problems in cold wet weather. I'll check the vacuum and see if there are any problems there.