Hello Car has a 3800 SC, and running what I believe is a stock 88 AC compressor from a 2.8.
Here is a picture of it. Can someone please confirm that this is a stock 2.8 compressor, as I need to replace it and want to make sure I order the correct one- (I thought the original one ran a V belt..)
I put the car on a hoist and pulled the AC compressor and AC line today.
Can someone more knowledgeable please chime in and look at these photos?
According to the original owner, he used an 88 Fiero compressor but used the pulley from a 3800. When I turn the pulley, there is a grinding/friction sound coming from the front (clutch area?)
The line was custom made. Isn't there supposed to be some kind of a high pressure switch on it to tell the PCM when to cycle on/off?
My plan is to get the compressor and clutch rebuilt, get the line pressure tested, and find the correct seals for the line and replace. We did lose pressure when trying to top up the 134A- something blew on the driver's side- probably a seal from too much refrigerant. I don't see any physical damage on the line
Please let me know if you recognize this compressor, if the pulley setup is a good idea, if there is a switch missing, and any other suggestions. Thank you
Peter
[This message has been edited by cam-a-lot (edited 06-02-2018).]
The grinding may be due to too little air gap, or a bad bearing.
Compressor does appear to be an HR6 with a 3800 pulley. The o-ring grooves tell us it's an old Fiero-era compressor, they stopped using these and went to sealing washers in the 90's. The black color of the o-rings means they are likely the original Fiero ones, and should be replaced with the new usually green R134A compatible ones. The high pressure cut-off switch is in the compressor, the little red one. The white one is broken, that's the fan switch. Good time to update both to the new style.
Some 3800 swap cars use a single 3 pin switch (GM part # 22571286) from the donor car attached to the hose assembly, but yours doesn't have that.
Would you mind sending me a link for the correct compressor (Rock Auto, etc?) I would rather also install a new 3800 pulley in case it is a bad bearing- I don't want to pull this out again. Can this be purchased new, or do I need to scavenge a 3800 compressor?
Four Seasons 58255 is the 88 V6 Fiero compressor, but it comes with the V-belt pulley. Try adjusting the air gap on the current compressor to make sure it's not the bearing. The 3800 bearing/pulley may or rmay not fit an aftermarket compressor, the pictures on their website look like it would work.
The 3800SC compressor is a V5 series, that would likely need the 3 pin transducer, since a V5 is a variable output compressor, and computer controlled, where the HR6 is controlled by the pressure switch on the accumulator.
can someone please confirm that the 4.9 compressor with serpentine belt would work and that the switches are compatible? Is there a specific name for the switches that I need to ask for when ordering them? Or specific application? Sorry about all the questions, but AC shops seem to be of little help here locally when dealing with a Frankenstein mish mash of parts on an old car.
The grinding sound seems to be coming from the "edge" of the pulley , so I don't think it is the bearing. I don't see any visual gap at all between the pulley and the clutch "plate" right at the end- that is where the grinding seems to be coming from. I only see one fastener in the middle. May try loosening it to see if this is what controls that gap between the pulley and the plate
I have found an AC Delco replacement for the original 88 compressor. The AC shop will install the serpentine belt pulley on it that was on my old one and make sure it is done correctly.
They advised me that the pressure switches will be updated to the newer style- and that my connectors in the car need to be changed.
Can anyone shed light on what changes I need to make to work with the new connectors on the switches? Is there a new set of plugs/ends I need to purchase?
Certain part numbers of switches come with new pigtails, all you have to do is splice one wire on the new pigtail (either one) to the original wire, and the other wire on the pigtail to a ground, most people use the compressor body.
Select one each of the 'Compressor Mounted' switches
Thank you- great info. It looks like the person who did the swap did not run any wires at all to the 2 switches in the compressor- there was nothing plugged into them. Only to the plug behind the clutch. I read in a few spots that the AC "may" work without these 2 switches being wired into the car.
Given that I don't know where the wiring needs to go from the switches, and that this is a 3800 swapped car so I don't know if the new wiring harness has made an allowance for these 2 switches, is it safe to run the system without them?
Safe, no. The system will run without them, but they are specifically safety devices. The high pressure cut-out especially, without this the system can literally go BOOM. Having the switch installed and operational can prevent potentially costly repairs or injury.
As an update, i have purchased a rebuilt HR6, and it came with what I believe are the old style switch(single brass post). Now I am trying find a connector for it, as unfortunately it doesn't seem like my 3800 swap harness has incorporated wiring for either one of these switches. So I need to figure out where they go and run new wiring. ;( Grrrr...
Can anyone give me a suggestion on what the correct connector name or part number is to connect to the red switch? I have a connector for the other one thanks to RWDPLZ earlier post- but can't figure out the red one.
Also, I just found out my condenser is original from 1988. I have no indication that it is leaking but was told I should use an AC flush solvent to clean the internals before installing a new compressor. Should I just replace the condenser instead while I am at it? I do have a new accumulator to go in, new orifice tube, and a new switch that plugs into the accumulator. Also have a seal kit and lubricant for AC.
I also found an old thread that may be useful to newbies like me who are struggling to figure out AC
Certain part numbers of switches come with new pigtails, all you have to do is splice one wire on the new pigtail (either one) to the original wire, and the other wire on the pigtail to a ground, most people use the compressor body.
Select one each of the 'Compressor Mounted' switches
The problem is the original wires that connect to the back of the A/C Compressor are gone including the AC Compressor control relay, the HPCO switch is simple as it just connects to ground. 1. The new two pin style LPCO will have one wire go to ground but where does the other wire go? Does it run up to the AC comp cntrl relay? Or go somewhere else?
2. Also confirm when using a 3800 engine with the Fiero A/C compressor do we still need any control input from the 3800 PCM or is this setup good to run on it’s own without any PCM input as I see on the original setup the stock Fiero ECM had some connections to the A/c system.
3. For the A/C Comp Cntrl relay wiring I have the light blue wire from C203 D going to the relay 85 pin. C203 N black and white wire going to relay 30 pin. A/C relay pin 87 going to A/C comp clutch. But where do I wire A/C relay pin 86 to?
Certain part numbers of switches come with new pigtails, all you have to do is splice one wire on the new pigtail (either one) to the original wire, and the other wire on the pigtail to a ground, most people use the compressor body.
Select one each of the 'Compressor Mounted' switches
The problem is the original wires that connect to the back of the A/C Compressor are gone including the AC Compressor control relay, the HPCO switch is simple as it just connects to ground. 1. The new two pin style LPCO will have one wire go to ground but where does the other wire go? Does it run up to the AC comp cntrl relay? Or go somewhere else?
2. Also confirm when using a 3800 engine with the Fiero A/C compressor do we still need any control input from the 3800 PCM or is this setup good to run on it’s own without any PCM input as I see on the original setup the stock Fiero ECM had some connections to the A/c system.
3. For the A/C Comp Cntrl relay wiring I have the light blue wire from C203 D going to the relay 85 pin. C203 N black and white wire going to relay 30 pin. A/C relay pin 87 going to A/C comp clutch. But where do I wire A/C relay pin 86 to?
Any reply to the last question would be much appreciated. FieroGuy and I are trying to put the car back together tonight and are stuck on this one wiring question
Car is on a hoist, just hoping for this last piece of the puzzle to be solved. Would be much appreciated if someone could help advise as to where the wiring needs to go from the 2 switches and the AC clutch plug on the 88 compressor into a 3800 swapped car.
thanks again everyone who has chimed in to help. Fiero_Guy's questions pertain to my car, as he is giving me a hand with it.
Peter
[This message has been edited by cam-a-lot (edited 06-30-2018).]
You can run the stock Fiero AC system with any engine (with or w/o an ecm)... Since you are sticking with the stock AC compressor, I would stick with the stock Fiero AC wiring, which doesn't need the 3 pin pressure sensor in the AC line. For the 88 V6 cars the cycling switch is up front and part of the chassis wiring ahead of the 203 connector. Only thing at the compressor is the clutch, high and (if used Low) pressure switches. Every switch and clutch on the compressor is wired in series from the relay +12V output (Pin B) to a ground.
Here is how I wired up the AC Relay on my LS4 swap:
Pin C (Dark Blue AC Relay wire) is the ground for the relay and should be wired to the AC Control pin on the 3800. The ECM uses this pin to disable cruise when you go WOT or above a certain RPM. HOWEVER, if you don't have the 3 pin pressure switch wired into the 3800, the ECM will likely not supply ground to this output, so you may need to wire it directly to a ground.
The 3800 ECM should also have an AC request signal that should see 12V when the AC is turned on. This is used to increase the idle speed for the AC compressor load. This should still work even without the AC Control wired up or the 3 pin pressure switch.
For my swap, the E67 ecm doesn't have a discrete AC Request input (done through the BCM and data lines), so I left it out and played with the idle air flows to avoid the AC stalling the engine.
You can run the stock Fiero AC system with any engine (with or w/o an ecm)... Since you are sticking with the stock AC compressor, I would stick with the stock Fiero AC wiring, which doesn't need the 3 pin pressure sensor in the AC line. For the 88 V6 cars the cycling switch is up front and part of the chassis wiring ahead of the 203 connector. Only thing at the compressor is the clutch, high and (if used Low) pressure switches. Every switch and clutch on the compressor is wired in series from the relay +12V output (Pin B) to a ground.
Here is how I wired up the AC Relay on my LS4 swap:
Pin C (Dark Blue AC Relay wire) is the ground for the relay and should be wired to the AC Control pin on the 3800. The ECM uses this pin to disable cruise when you go WOT or above a certain RPM. HOWEVER, if you don't have the 3 pin pressure switch wired into the 3800, the ECM will likely not supply ground to this output, so you may need to wire it directly to a ground.
The 3800 ECM should also have an AC request signal that should see 12V when the AC is turned on. This is used to increase the idle speed for the AC compressor load. This should still work even without the AC Control wired up or the 3 pin pressure switch.
For my swap, the E67 ecm doesn't have a discrete AC Request input (done through the BCM and data lines), so I left it out and played with the idle air flows to avoid the AC stalling the engine.
Thanks Fieroguru, What about the compressor fan switch on the compressor should I wire it to C500 pin D so the coolant fan will always be on when the A/C system is running? If not where do I connect the wire? This switch on the rear of the compressor is a two wire switch one goes to ground just need to know where the other should go. C500 pin D seems like the correct location. I drew up my own diagram putting all the connectors on the compressor, the high pressure is a single wire. https://imgur.com/gallery/Meh39bZ Thanks again for your help.
[This message has been edited by Fiero_Guy (edited 07-01-2018).]
Yes, Two compressor switches are low and high cutoffs. Plus clutch and control switches up front. all switches close on request input allows ECM/PCM to close relay and run the clutch coil.
Your PCM can't do that? Then have 2 problems minimum besides how you wire. Won't boost idle to keep engine running when clutch slapper DR6/HR6 activates. You can stall often in slow traffic, stoplights, etc. Won't turn off AC at/near WOT... 2 things that does is to hurts engine power and can over rev the compressor killing it. If you think AC is a crap job now... 10+ times worse if compressor dies of "Black Death." Basically Compressor can blow crap like piston rings and small aluminum pieces throughout most of AC before totally dies. If Compressor locks can break belts and worse. If compressor leak more then few drops of oil the exhaust and cat is right there.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Thanks Fieroguru, What about the compressor fan switch on the compressor should I wire it to C500 pin D so the coolant fan will always be on when the A/C system is running? If not where do I connect the wire? This switch on the rear of the compressor is a two wire switch one goes to ground just need to know where the other should go. C500 pin D seems like the correct location. I drew up my own diagram putting all the connectors on the compressor, the high pressure is a single wire. https://imgur.com/gallery/Meh39bZ Thanks again for your help.
The fan kick on is handled up within the HVAC control, so you don't need to worry about it. There is no fan switch on the compressor, just the clutch, high pressure switch, and low pressure switch (if used) and all 3 are wired in series.
I assume the compressor has not been charged yet, so use a mult-meter and check for continuity on the single terminal switch and the case of the AC compressors. If it is the high pressure shut off, it should have continuity (it will open the circuit when the pressure goes above a certain point). Check for continuity between the two terminals on the other switch, they probably will not have continuity as they likely need to see system pressure to close the circuit.
If the tests checkout as described above, then run the +12V wire coming from Pin B on the relay to Pin B on the clutch switch. From pin A of the clutch switch, run a wire to Pin B of the 2 wire switch. Then run a wire from Pin A of the 2 wire switch to the single wire switch. That should allow the AC clutch to engage and run (when the compressor is charged).
You should also T off the +12 wire from terminal B on the relay and run it to the AC request pin on the 3800 ecm. This should let the ecm know when the AC compressor is running and even without the 3 pin connector it should bump the idle when the AC clutch is engaged.
If you are going to race or go WOT, turn off the AC first. If you don't, spinning the pump too fast will over pressure it and the high pressure switch will kick it off, but once the pressure drops, the clutch will re-engage. You don't want the AC clutch to engage with the compressor stopped and the engine at 5000 rpm as it will over stress your accessory drive and likely break the belt, throw the belt, or possibly bend and break one of the accessory mounts.
You can fix the WOT issue by installing the 3 wire pressure switch and using the 3800 ECM AC Control pin to ground the AC relay.
Since I plan to keep this car forever, and really don't want to rip apart my AC again, in your opinion, would it be better for me to buy a 3800 compressor instead of trying to mix and match the HR6 compressor on the 3800 motor?
I can probably re-sell the HR6 compressor as it is a brand new AC delco unit- assuming the 3800 compressor won't have intereference problems with the WCF headers.
I do have a new AC line from BMW Guru I bought a few years ago, that has the extra "bung?" for a sensor in the line. I believe that is what you were talking about for hooking into the PCM
thanks for any input
Peter
[This message has been edited by cam-a-lot (edited 07-04-2018).]
Since you already have the line with the port for the 3 wire sensor, I would go that route. Just get the sensor and wire it to the 3800 computer, and install the compressor. The 3800 compressor is smaller, too.
Either way will work, it really depends on how you want it setup now and for the future.
There is something to be said for keeping the alternator and a/c compressor that matches the engine swap. Not only is it a newer part that will be available longer, it also makes it easier to get parts later if they are all match the engine.
What A/C wires does the harness currently have? You might check the ecm pinout and check to see if there wires for the pressure switch are at the ecm connector. If they are, they might be wrapped up in the harness if they are not near the compressor clutch connector already.
It is starting to look like the consensus is that I would be better off to just put on a 3800 compressor.
My bottom end is an L26. Can someone confirm that AC Delco 1521511 looks to be the correct compressor for that motor?
I have a line from BMW Guru that I believe was for the 3800 to Fiero line and has the correct port in the high pressure line. Hopefully it will be long enough to work with my WCF headers.... Off I go to waste more money on my AC system and go buy another compressor ....grrrrrr
