Need AC help!

Hey guys...so I replaced my whole ac system in my 95 3.4...New Denso everything.. Compressor, condenser, evaporator,expantion valve. All new O rings. Put the proper amout of oil in the compressor. I ran a vacuume on the system for well over an hour, and it held vacuume over night. I was so happy. So this morning I put in the 134a...Put 22oz in...the compressor kicked on as it should. But it is NOT cycling off! The compressor is running non stop and the clutch never disengages unless I turn the ac button in side the cab off. I tried adding another oz of freon but nothing. The compressor runs constantly. Which is making my Hi side pipe very hot and the truck is not getting cold in side inside the cab. PLEASE no comments telling me to take it to a shop! LOL But any help would be awesome. Note...I did not replace the pressure switch because it kicks on when I added the freon...so assume its good. Could the AC amplifier cause this issue??? Thanks Mike

 

Was everything working prior to replacing the parts? I just did this same thing, replaced everything with DENSO so just went through this process. I would check the pressure switch because it should control the min and max pressure, which kicks off the compressor when PSI rises too high IIRC.

If youre using manifold gauges, what PSI do you have on each side?

 

I saw some vid that compressor would not turn off bc of a faulty HVAC switch on dash…..was always sending power to compressor

but the hot hi side pipe points to over charge

definitely agree with travis500 about using gauges to see what each side pressures are 1st

 

Well I put the mani gauges on it...Hi side reaches from 150 to 200psi and the low side I have 0 psi. The only thing I can think of is that I got a bad expansion valve. I dont see it being anything else. What do you guys think??? Its been a while since I got a defective part fron Denso but it has happened in the past.

 

I would double check that 0psi, seems weird to me, figured there should be some psi, even if super low.

but yeah a bad expansion valve could certainly be a potential cause, or the compressor. Idk if the denso quality on these compressors is becoming shiet… but the first one I received was bunk too, needed to return and replace.

 

Well...just found out the low side guage on my harbor feight guage set is on the fritz! Imagine that!

 

@taylor555 ever get it sorted?

 

My China Freight gauges leaked/blew freon out of the manifold first time I used them,, junk, I knew better than to trust their junk, I thought. Only hand tools for me from that place.

 

Ah, did you end up getting all the AC fixed?

 

Nah, I went to my buddies shop and he topped it off for me,,,,, much better fix anyway, he has that knack for AC's.

 

They made nice manifold sets 20 years ago, but HF...

 

Yep...got it all fixed. My pressure switch by the evaporator was leaking.