Erratic AC behavior on '96 Villager

I have an strange issue with my AC, when I turn it on on Max setting and start my driving while accelerating it "feels" when compressor disengage and blows hot air, then when in idle it will start to cool...another strange thing is when I put blower knob on #3 it will work ok most of the times (accelerating or in idle) but when outside temp is high (around 90 F or above). So at nights I do not have problem with my AC, even on maximun setting, just when the outside heat is high.
I have recently replaced radiator and water pump so engine temperature is "normal"...anyway, even if I start the van at noon (after let engine cool since last night) I get this erratic behavior, but if I do it in the morning it works fine and this confuses me.

I read a little about checking pressure switch and bypassed it but has the same behavior.

A friend of mine told me about van's computer shutting off the compressor, but I don't think so...

Anyway, somebody has any idea how to fix this ???

Thanks

Is your check engine light on?

Go to autozone and have the codes read to see if any are stored.

When was the last time the AC was serviced, check the low and high pressures with a AC Gauge system. Do you have both front and rear AC?

Is your check engine light on?

Go to autozone and have the codes read to see if any are stored.

When was the last time the AC was serviced, check the low and high pressures with a AC Gauge system. Do you have both front and rear AC?
No, I don't have engine light on.

Will check for codes.

Last service on AC was May '07. And yes, I do have both AC working...need to check pressures too.

Thanks

Was this condition existing before radiator and water pump replacement?

Was this condition existing before radiator and water pump replacement?

Yes, it was present

I had leaks in radiator and water pump so were changed. As a matter of fact, I was told PCM shuts off AC compressor in a presence of high engine temperature to avoid overheating. And I was kind of hoping problem to be solved doing this repairs. Also right now I don't have thermostat installed.
Engine temp is now "cooler" than before, but this problem persist.

I wasn't able to retrieve the codes and I will do it in this weekend, but I was hoping to have some info for start messing with the AC system.

I am thinking that either your system is low on refrigerant or the Engine Coolant Temperature Sensor is faulty, but I would check the low and high end pressures first.

I assume that you have the manual controls versus the climate control.

You could try posting your problem at [email protected]
Free and helpful people there also along with files and photos on many diagnois.

Keep us posted

Thank you Tempfixit...I will check this weekend codes, pressure lines and the engine coolant temperature sensor.
If everything is ok... I will try asking on yahoogroups...and of course will keep posting my findings.

Thanks again, it is nice to find people like you willing to help others

I couldn't get the pressures...the mechanic did not had right couples to get the readings.
Reading the codes we found that computer has stored code P0325 (Knock sensor)...but my engine light is not on.

I couldn't get the pressures...the mechanic did not had right couples to get the readings.
Reading the codes we found that computer has stored code P0325 (Knock sensor)...but my engine light is not on.

I assume that your mech erased the knock sensor code. A knock sensor code on these vehicles means that something is causing the knock sensor code NOT that the knock sensor itself is faulty. I would check again after a few miles of normal operation to see if the code has returned.

Thinking about your A/C problem I am thinking that it is freezing up. I am not a A.C person but it seems to me that if this is happening that you should see ice build up on either the evaporator or condensor I can't remember which. Just a thought.

Yes, code P0325 was erased, will check to see if comes up again.

Regarding your thought checked that and found no evidence of freezing.

I was able to check only low pressure and it was at 80 psi at idle rpm (don't know if it is fine for this vans), once I accelerate to aprox 2500 rpm drops to 65 psi (compressor cuts of) and then build up pressure that go beyond readable, once again compressor comes in but almost immediatly cuts off again, then If I leave engine at idle I got what I think "normal" operation of the compressor.

Yes, code P0325 was erased, will check to see if comes up again.

Regarding your thought checked that and found no evidence of freezing.

I was able to check only low pressure and it was at 80 psi at idle rpm (don't know if it is fine for this vans), once I accelerate to aprox 2500 rpm drops to 65 psi (compressor cuts of) and then build up pressure that go beyond readable, once again compressor comes in but almost immediatly cuts off again, then If I leave engine at idle I got what I think "normal" operation of the compressor.

From what I have read in the FSM for a 94 Villager the low side pressure should be 24PSI to 47 PSI at 1500RPM. You need to watch both low and high side pressures at the same time. I am not sure that these values pertain to the 96 or are different but I would think they are close to the same.

I was hoping someone else would be able to help but I quess that's not happening so I STRONGLY suggest posting your question with as much of this info you can at the forum I mentioned in a earier post in this thread. I believe someone will be able to help there.

Sorry I cannot be of more help but I don't want to lead you to throwing parts at it without any results.

Send me a PM with your email address and I will forward you some information that I think will help you out.

Well, I already sent you a PM....

I'm really glad that at least you helped me, will try lowering the pressure this weekend, you know I haved a loaded agenda (je,je who am I trying to impress), so if I can't get good results then I will post on yahoogroups.

Thanks tempfixit

Check your Ambient Air Sensor, check this link for what it looks like:

http://www.partsamerica.com/ProductList.aspx?parttype=756&ptset=A&searchfor=Air+Charge+Temperature+Sensor

or

http://www.partsamerica.com/ProductList.aspx?parttype=272&ptset=A&searchfor=Air+Cleaner+Temperature+Sensor

Finally a friend of mine got the pressure down to 45 psi, it improves but still getting this "compressor off" sometimes (specially when accelerating), at least now last a little bit longer when cruising.
So I might see this Ambient Air Sensor you mention...and to my bad luck I'm getting my battery drowned of energy since saturday...after my friend did his work on the van...I will need to check on that too, because I notice lights go dim when I turn on the AC.

Thanks again tempfixit on your tips

PD I wonder if you have information about electrical system that you can share with me.

In addition code P0325 appeared again, I believe It needs to have a tune up, but it is just aprox. 2000 miles since last one, also I have read about on cleaning MAF sensor...maybe helps.