I have a new compressor. When I turn on the system the compressor runs for about 4 seconds and then cuts off. There is plenty of freon as I evacuated the system and pulled a good vacuum and reinstalled 30 ozs of gas.

The low pressure switch isn't the problem as I jumped it out. Same for the high side.

I switched all of the relays in the PRB around in an effort to isolate the WOT/AC relay in case it was bad. No problems there either.

Other than something internal in the compressor, I am at a loss.

Any suggestions?

 

Have you connected an A/C manifold gauge set, trouble shooting the system without it is folly... Philip

 

Look, AC systems are complex. It is not something you can just go and replace parts and then expect it to work. You need to get yourself an AC manual, get yourself the appropriate tools, and study how to use them before you ever touch an AC system.

Let me guess, someone told you your compressor was bad, you didn't like the price you were quoted to replace it, so you decided you could do it yourself.

Hate to break this to you, but when a compressor fails, it is not the only thing you need to replace. There is a reason having a pro repair an AC system can be expensive, its because everything has to either be flushed or replaced. Chances are that unless you flushed the system and replaced the orifice tube, accumulator, and possibly the condenser (some don't flush very well), then you have just ruined your new compressor.

Also, don't call R134 freon. Freon is a trade name for R12. I know some will argue that it is an interchangeable term and that everyone calls it freon. This is not true, professionals call it refrigerant or R134. Promoting confusion and perpetuating incorrect terminology is not a good thing.

 

You need to post the actuall pressures on the high and low side that you are seeing. Jumper out the low and hi switches should isolate that, but not a real good idead. What pressures are you seeing.

 

Khan....dude....take a pill man.

I have owned my own an a/c business for over 20 years and have been a tech for much longer than that. I hold valid hvac licenses in 17 states and have performed hvac work in everything from an auto zone to a 50 story skyscraper. It is a lock cinch guarantee that I know more than you when it comes to a/c. In fact, car system are actually refrigeration and not a/c.

Not that it really matters.

I said freon instead of 134a because, in fact, most folks don't know that. I didn't want to offend anyone who might know less than me, or worst, come off like a pompous ***.

I guess I didn't need to worry about that.

The reason I posted (and I'm damn disappointed I did) was because I was hoping there was a relay or switch I wasn't aware of that I could go directly to and test or replace. The fact that knew about the WOT relay should have been a clue to you that I did do some research and this post was about me doing a little more.

My knowledge about vehicle systems is limited to my 20 years of experience with a/c and that's it. My knowledge of the entire electrical system for a 1996 Exploder is limited at best. That's why I asked my question.

Instead of getting a little direction, I get a pompous *** who did nothing more than cement my opinion of pages like this. Pretty much full of guys who know a lot about one thing and get off on running down people who don't know as much.

 

I'd first check to see if you have power to the clutch coil when the compressor kicks out. If there is power to clutch field coil, but the compressor stops spinning, that would likely suggest that the clutch is worn or the field coil is not working properly.

If you are not getting power to the coil after the 4 seconds, then pull the WOT relay and check for voltage across the WOT relay coil terminals (85 and 86). If you retain power here even after the 4 seconds, then the relay may be bad (unlikely since you swapped it out) or there is some function of the system that, when the compressor is running, tells the system to disable the clutch after a short time (more likely). That's where noting how the pressures react on the low and high sides will come in handy.

If even with the WOT relay removed, if the power to the relay coil drops out after a few seconds, there is likely something causing the PCM to disable the A/C after just a few seconds. For that I suppose I'd start looking at the TPS sensor and connect a high end scan tool to see what the "A/C Request" parameter is doing. It could also be possible (but unlikely) that there is corrosion in one or both of the feed circuits for the relay coil that prevent it from supplying enough current to keep the relay engaged. This would only be noticeable if you used a test light to check for coil current versus a high-impedance multimeter.

-Rod

 

I forgot to add that per the factory service manual, the WAC switch is open at or above 430 psi and is closed at or below 260 psi. The cycling switch is open at or below 24.5 psi and is closed at or above 43.5 psi. Although, again, since you bypassed these at one point they are not likely to be the culprits.

-Rod

 

Had you apprised us of your prowess and qualifications. I am sure that many of the respondents would have held back on their limited suggestions....and left you to your own devices......

You should be able to read and understand a simple schematic...and you are intimate with refrigeration..... Philip

 

Geez! A guy knows A/C, not totally familiar with a particular application, tells what he's done, still in the dark....

Gets cut down for not knowing......

Then EVERYONE starts a pissing contest.....,.

Wonder why there are more informative and tolerant forums?

impish

 

Everyone was willing to assist, until they were rudely informed by the PO that he knew it all, and dint need amateurs....

What did you/he expect? .......Philip

 

Look....Khan was incredibly condescending. No question. I got my back up, and in this particular instance, decided to brag. Given the circumstances and if you were in my shoes, most of you would have responded in the same fashion.

The qualifications I listed are genuine. If this issue were about a/c systems only, then I probably wouldn't need any help. I feel like the problem is deeper than the obvious so that's why I came here. For the life of me, I never thought in a million years that someone would tell me

"You need to get yourself an AC manual, get yourself the appropriate tools, and study how to use them before you ever touch an AC system."

That fool has no idea who I am or what my qualifications are. Just so happens that I am qualified to pick up my tools and have probably been using my tools of the trade longer than he's been alive.

But, I also have been around long enough to know that I can learn something new every day. Especially in hvac. That's why I didn't come blowing in here about what I know or don't know.

I JUST WANT TO FIX THIS CAR.....lol

Since Khan didn't have the answer, or didn't want to tell me the answer, and those that wanted to pile on don't have or want to tell the answer, then I guess I'll go with Shorod's answer. His makes sense, gives me a place to start and is very easy to read.

 

What are the readings on your gauges?

 

i had not thought about the clutch letting go. Might be that you have voltage all the time to the clutch, but air gap is too big and drops the clutch when you build up load (pressure)????