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I have a spare head unit from my S4 but the functionality is slightly different on the GTS to the earlier models. Much appreciate if you [or anyone else] can opine on whether I can slip this unit in and it will still work without anything going pop. I never use the additional feature [it has a circular icon] and would be quite happy if it functions same as the S4 but no idea whether it is plug and play or everything catches fire and melts.
Rgds
Fred
Question needs to go to the guru, Greg Brown. Since there's no such thing as anything less than full-effort on anything, Greg has assembled a whole test fixture for system components, so he can plug in any suspect piece and tell immediately if that piece is the problem.
Greg -- do you make any changes to the test fixture between S4 and GTS head units?
Electrical guru Alan would also know, as he's done a lot of work on his GTS control head.
That sounds like a good idea. I'll research this...
If you have not fried the head unit yet, just add a power relay and power wire down by the AC compressor. Fog light relay controlled by the wire from the control head, fused power from the jump block to power the AC clutch. The sad little relay in the control head is safe as kittens.
Also if you are considering an R134A conversion, look into R152A instead. It's working great in my formerly R12 system in my 1992 968. Cheaper than R134A, easier on the environment, better performance, no downsides detected thus far.
It pretty much rained all weekend for me. Friday was spitting and sputtering miserable rain, then poured in the evening. Saturday was clear until the evening, in which it poured.
Friday afternoon, after puttering around on other things, I went ahead and pulled a vacuum on the AC system. It pulled right down to 29". I did a quickie pull, leaving vacuum on for only 30 minutes. I let it sit for 15 minutes. Vacuum rose to 24". So there was a leak of some kind.
I charged the system with two 12oz cans of R134a. It was pouring rain at that point. I figured two cans would be plenty for testing purposes.
Late Saturday morning, I put the gauges back on the system. To my surprise, there was 68PSI static pressure in the system. So, I started the system and added enough R134a to bring low side pressure to around 25PSI. Not scientific, and not necessarily to the R134a temp/pressure chart, but good enough for the moment.
I tested the sniffer against a whiff of refrigerant from the manifold gauge set. It wigged out and triggered all 6 LED's. So, it did react to R134a. The sniffer is listed as being for R12.
With the system static, I ran the sniffer wand all around the AC system. Never once did the sniffer react. I checked the following:
-expansion valve
-fuel cooler
-receiver/drier
-evap pipe to condenser connection
-compressor clutch
-condenser
Nowhere did I get a beep. Hmm...
I did not get a chance to jack up the Red Witch and look underneath.
Due to the rain, and late start, I elected NOT to overhaul the AC on Saturday. This was a rare bout of foresight for me. I wasn't comfortable that I could get everthing done and back together by 3pm Sunday afternoon. The pouring storm Saturday evening confirmed this decision.
I work Third Shift, and will be working 12 hour shifts for the next 8 days. So, I could not leave the Red Witch in pieces. I decided to just keep putting R134a in the system as necessary. After SITM, I will deal with the AC.
On a good note. Roger came through with the last of the AC pieces on Saturday. Damned glad to have his help.
Because I will be going into work early, I will be running the AC in the late afternoon heat. I will keep track of how often and how much R134a I have to add. Good think Wally world has it on RollBack for $4.88 a can.
I will bet you will catch a leak on the flex lines at the passenger side front of the engine compartment. The rubber gets hard and the leak where they connect to the metal. If your sniffer doesn't pick anything up try flexing them a bit and see if it changes. They were probably flexing about on your trip while driving the car and that's why all the refrigerant is gone.
If you add the relay in the engine compartment to an early car, add a couple of diodes and a lead to the electric fan. The AC switching for the fan on the early cars sucks...
Cosmo Kramer: You have a very good point. One I don't want to listen to, but good nonetheless. That is the hose I can't replace or repair at this point. My plan after SITM is to get the Red Witch up on her Liftbars and jackstands. Pull the belly pans off and have a good run with the sniffer.
I have to figure out how to flex that hose with the engine running and not get hurt...
Wally: Please explain. Early meaning early 80's or anything before 1987? I had intended on adding a second relay just for the auxiliary condenser fan. However, I saw that the XVIII relay is for A/C condenser fan. I figured it is good.
If I am wrong, I will wire in a relay with fused power from the ABS junction block on the driver's side.
Thanks for the heads-up!
If you add the relay in the engine compartment to an early car, add a couple of diodes and a lead to the electric fan. The AC switching for the fan on the early cars sucks...
What's wrong with the AC fan switch on early cars? Mine seams to work good and the temp switch will turn off the fan at speed when you have enough air flow to cool the AC (and radiator).
Tuesday evening, I ran the AC on the way to work. The air it put out didn't even qualify as 'cool.'
When I stopped for fuel, I checked under the hood. The compressor was running, so there was something left in the system.
I drove the Explorer last night.
This morning, I put the manifold gauges on the AC system. Surprise, it had 80PSI static.
I started the engine and the AC, the. Slowly fed a little refrigerant in. After a bit, I had 30PSI low side, 190PSI high side, with the auxiliary condenser fan running. Ambient temp was in the low 80's. I know this is ghetto, and you are supposed to charge by weight. But I am doing troubleshooting and just want it in the ballpark.
With the above pressures, the air coming out of the vents was somewhat cool. Hmmmm...
I am going to run the AC this evening on the way to work. I want to see how it does with highway speed air flow across the condenser.
I now wonder what else is wrong?
Expansion valve inop?
Compressor failing?
I don't think the condenser is plugged, because high side pressure is not super high.
When I get the system apart, I am definitely flushing everything. I have a flush gun and a gallon of AC system flush.
Check to make sure you have vacuum at the heater valve, center vent comb flap and recirculation flap all of which can introduce various amounts of hot air into the equation. When I first got my car I found the rubber manifold at the back of the vacuum solenoid was completely shot and drastically improved in cabin temps when fixed. It's the black rubber piece on the picture of the solenoid from Dwayne's guide.
Imo000: Very good question. I will have to pull the blower motor and find out.
zekgb: Very good to know! If I get a day off this weekend, I will dig into the console for a look-see.
Thanks!
So, the drive to work this evening went better than expected. AC started right off blowing cool air. The longer I drove the colder it got. It never got 'cold' cold, but it did get comfortable. I'd say the AC is now back to where it was when I drove back from Ohio.
I am going to follow Dwayne's troubleshooting guide and go from there, at least until I can overhaul the AC system.
Hi Seth,
It sounds like your system is working suboptimally, but not that badly with air flow through the condenser. You also seem to have a leak which is difficult to find. One trick to find a compressor seal leak is to wrap the compressor clutch/pulley in plastic and let is sit overnite, then try your sniffer.
Make sure your heater valve is fully closed, as others have said.
Good luck,
Dave
could be over charged now. how much have you put in?? did you do the sniff test to the Evaporator in the car?
i fought with bad AC for years. FINALLY, just took everything out. all new o-rings, lines, condenser, dryer, expansion valve..... only thing that was not new was the hard lines and the evaporator.
the only R12 lines lack the inner lining that keeps R134 in the lines. think of R12 as having "large" molecules and R134 as having small ones. all the new lines from porsche come with the newer lining.
could be over charged now. how much have you put in?? did you do the sniff test to the Evaporator in the car?
i fought with bad AC for years. FINALLY, just took everything out. all new o-rings, lines, condenser, dryer, expansion valve..... only thing that was not new was the hard lines and the evaporator.
the only R12 lines lack the inner lining that keeps R134 in the lines. think of R12 as having "large" molecules and R134 as having small ones. all the new lines from porsche come with the newer lining.
I agree with the above. I had my lines rebuilt by a shop in Tuscon, very cheaply, and quickly. That and all new except hard lines and evap, including a PF condenser.
Has worked great for the past five years. (knock wood)
Good luck,
Dave
j.kenzie@sbcglobal.net: Dave, you are correct. I like your idea for wrapping the compressor. That is slick. I will check the heater valve next time I am working on the AC system. When I had the air box off, I saw the heater valve, but didn't notice anything obviously wrong with it.
How worthwhile an upgrade was the parallel flow condenser? Did you have to change the headlight motor and/or linkage to get it to fit?
Ducman82: Distinct possibility of overcharging due to me only charging based upon temp/pressure. I do not yet have an effective digital scale that will go down to the ounce for precision. Initial fill after pulling a vacuum was 2 full 12oz cans, then topping it off as required over the next few days. I lost a little refrigerant from a test fitting coming loose while working. So, I had to top it off again. I am not just randomly shoving refrigerant in. I am checking static pressure, starting the system, letting it pull down to 20 or so, then slowly adding refrigerant until the low side pressure is around 25-30PSI, depending upon ambient temperature.
I did not do the sniffer into the evaporator. I will try that on the way to work Saturday evening. I will have the sniffer on the console and the probe in an AC vent.
This evening, on the drive to work, the AC was not terribly effective until driven several miles. It seemed to be a gradual cooling effect. Think slowly cooling the same recirculating air. It got comfortable eventually.
I am mostly going with you approach, though as of this moment, I am not replacing the condenser. Or the flex section in the evap hardline. I have new Porsche compressor hoses, remanufactured Denso compressor, new receiver/drier, new expansion valve, new pressure switch, and a large bag of O-rings.
Next full weekend I have off, I am ripping it all apart, flushing the h*ll outta the evaporator, condenser, and hard lines. Then reassemble with tender loving care.
05-20-2016, 04:42 PM
