1989 f150 5.0 5 speed.

Ok I've just left the compressor unplugged for the past year. I ran a can of r-12 in the system and the compressor does cycle but everytime the compressor cycles it almost kills the truck about 500 rpms, after it's done cycling it revs the truck to 1500 rpms.

I ran just one can in the system and it didn't get too cold , just trying to narrow down the problem.

When I bought the truck 3 years ago the a/c cycled normally, then I charged the system a year in owning it, about 4 months after charging it is when this problem started to occur.

I've only ever ran r-12 in it.

One of my friends questioned it may be the icm or the compressor clutch could be locking up.

I've been doing alot of work to the truck to make it road-worthy again and this is my last issue.

Any suggestion's would be appreciated.

 

Hmm your friend suggested the compressor clutch could be locking up. . . what was your first clue other than thats what it's supposed to do. . . more than likely since you unhooked it for a year the compressor is seizing up.

Keep in mind the A/C compressor will still cycle in defrost. which meant if you unhooked the compressor that it just sat there and had the chance to rust up inside

 

well I unplugged it because that problem started to occur 4 months after charging the system. it has been unplugged ever since then though.
If the compressor wouldn't had tried killing the truck in the first place I would have not unplugged it, I couldn't run the defrost in the winter because of this,
so I had no choice but to unplug the compressor.

Again the a/c was functioning fine until after 4 months of charging it initially, Then I had this issue and it has been unplugged ever since.

Trying to see if idle valve or anything else Idle related could cause the compressor to react like this, before just throwing a compressor on there

 

The compressor could just be on its way out. Have you tried turning the compressor by hand? If its really hard to turn its probly starting to shell out.

One can wouldn't make it cool if it was completely empty, you won't know for sure what it's doing until you put a set of gauges on it.

Personally if it was me, I'd put a new compressor, orifice filter and switch it to 134a. IF the compressor hasn't contaminated the whole system. If you take the hose off on the pass side at the evap where your blower motor is the filter is in there, look at it and see if there's any shavings. Just remember when you open an a/c system you have to put a vacuum on it before charging to take all the moisture and air out.

 

A year of non-use? Yea, compressor is bad. These compressors are junk brand new.

 

Yea, that's what me and my friends were thinking, thanks for the second opinion guys.

Time to spend more money

 

Who really needs AC anyways. Mine works wonderfully and I'll only use it in the heat of summer maybe once every week or two just to keep things flowin

 

Who needs a/c? People with a wife and children that want to join in on 20th century technology.

 

Ha...my thoughts exactly.