When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I've done my research but haven't been able to find anything with the same situation as I am experiencing.
A/C was brought back to life with new seals and covered valves for charging with 134. Vaccumed and charged.
When initially turned on the system starts to blow cold air but then the I can see that the clutch is engaging on and off repeatedly. Thus blowing warm air.
So I'm trying to figure out if the Clutch is bad or the sensor needs replacing.
So I've done my research but haven't been able to find anything with the same situation as I am experiencing.
A/C was brought back to life with new seals and covered valves for charging with 134. Vaccumed and charged.
When initially turned on the system starts to blow cold air but then the I can see that the clutch is engaging on and off repeatedly. Thus blowing warm air.
So I'm trying to figure out if the Clutch is bad or the sensor needs replacing.
Thanks!
Excessive compressor cycling with weak/inconsistent cooling can also be a symptom of an overcharged system.
So to troubleshoot the described symptoms, the 1st thing I'd do is hook up a manifold gauge set, run the car at a high idle and turn on the A/C, fan at MAX. While the compressor is engaged and the cabin is starting to cool off, make note of your high & low pressure readings, and make note of the ambient temperature. Refer to the FSM - there's a chart that shows what "normal" H/L pressures should be for a properly charged system relative to ambient temperature - that will tell you if the shop over/under charged your system. Then keep watching the compressor clutch while the AC is still on, and note the high/low side pressures again on the manifold gauge whenever the compressor disengages/re-engages. This will help you rule out the binary pressure switch - FSM has specs for that too. Don't recall the specs off the top of my head, but the switch should be closed (compressor engaged) for pressures above around ~20psi but below ~300psi or so. There are also two thermal switches in the A/C clutch circuit that can cut off the compressor under specific conditions too. One of these is on the compressor itself, and it cuts off the compressor if it gets too hot. The second one is installed on the evaporator core, and it cuts off the compressor when the temp of the evap core approaches freezing, to prevent condensation from freezing over on the core. With the help of the FSM/wiring diagram, you can bypass each of these switches with a jumper wire for testing purposes.
You can only put the hoses on the correct fitting, and that's intentional. Cause if you could hook a can of refrigerant to the high side in operation it would likely explode.
I would watch a few videos about using the gauges to diagnose your issue.
2 easy possibilities:
1) Compressor engaged, and the low side starts dropping and high side starts climbing. LOW side drops too low and compressor disengages.
Typically that's low on refrigerant and you need to add a little more.
2) Compressor engaged, and low side starts dropping, and high side starts climbing quick. HIGH side goes way high (300+) and compressor disengaged.
Typically that's either too much refrigerant, a clogged condenser, or poor airflow across it due to electric fans not moving enough air.
One other thing worth mentioning, if the system was opened, it needed to be pulled to vacuum to remove all air and moisture from the system before recharging.
Do you have a power FC? We had to bypass the circuit to the power FC in order to get the compressor to work consistantly. Something about the signal from the power FC not getting through to the relay.
You can only put the hoses on the correct fitting, and that's intentional. Cause if you could hook a can of refrigerant to the high side in operation it would likely explode.
I would watch a few videos about using the gauges to diagnose your issue.
2 easy possibilities:
1) Compressor engaged, and the low side starts dropping and high side starts climbing. LOW side drops too low and compressor disengages.
Typically that's low on refrigerant and you need to add a little more.
2) Compressor engaged, and low side starts dropping, and high side starts climbing quick. HIGH side goes way high (300+) and compressor disengaged.
Typically that's either too much refrigerant, a clogged condenser, or poor airflow across it due to electric fans not moving enough air.
One other thing worth mentioning, if the system was opened, it needed to be pulled to vacuum to remove all air and moisture from the system before recharging.
Vince
Thanks Vince for the advice. The system was vacuumed so it could be the amount of freon. I'm going to get my hands on a set of guages and follow the steps provided here.
Do you have a power FC? We had to bypass the circuit to the power FC in order to get the compressor to work consistantly. Something about the signal from the power FC not getting through to the relay.
Best bet is to monitor all haltech air conditioning input and output parameters and log this while it's happening. That way you can see if it's a signal/control issue from the EMS. Next put a set of gauges on it. Air conditioning systems have pressure sensors on them where if there is a blockage and the high side pressure goes beyond a limit it opens the circuit to the compressor to stop a catastrophic failure so even though the EMS is sending the compressor "on" signal there is a physical break in the signal circuit as a fail safe. Same thing with low pressure, if there isn't enough freon to trip the low pressure switch it won't turn on the compressor so you don't burn it up (which doesnt sound like your scenario.) You will see this on the gauges right away when the A/C is cycling.
I got my hands on a set of gauges. When reading what the FSM says it appears that the gauges are reading high. Can someone confirm? At idle the clutch doesn't disengage, only when revving.
https://photos.app.goo.gl/SVv6kA1v53voj6b27. This is a video showing how the gauges react when accelerating. The effect your seeing is the clutch of the compressor engaging and disengaging.
the middle reading looks odd. The pressure readings correspond with the ambient temperature. The FSM is for 68F. I'm sure it is hotter than that in Austin, so your readings should be higher.
Agree that middle photo reading looks weird but maybe it isn't - what was going and when that shot was snapped? The only time your low side pressure might be that high is if the picture was taken just as the compressor was being switched ON after being off for a lengthy period of time; i.e., in that case what you're seeing is both sides transitioning from their normal STATIC pressures (where both H/L sides should be at equilibrium at roughly 90psi or so, depending on ambient temp), to normal operation, where the suction (L) side should drop to around 15~35psi or so and pressure (H) side builds to about 175~300psi or so, depending on ambient temps.
Ok, now that I looked at the video showing the pressure gauge readings while the compressor cycled on & off, I've got a couple of thoughts:
1. When the compressor is engaged at idle, LOW side pressure is a bit higher than it should be, and as you rev the engine up, the HIGH side is climbing rapidly to almost 400psi and hitting the high pressure cut-off. So it appears your binary pressure switch is doing what it is supposed to do.
2. So the question is why are the system pressures higher than they should be? Most likely answer is the shop simply overcharged the system - too much freon = too much pressure. But it could also be the result of having air or moisture trapped in the system; the air/moisture freezes, and blocks refrigerant flow at one of the choke points, typically the receiver/dryer or expansion valve. This can be caused by sloppy workmanship (e.g. failing to bleed the yellow charging hose of air before charging, having the A/C system plumbing open to the air for a lengthy time, and not installing a new dryer when it was open while all the other seals were replaced)
As for what to do about it, you can first try to have the system evacuated again & recharge by weight to the correct amount of refrigerant. That will fix it if the system was simply overcharged. If that doesn't work, I'd replace the dryer with a new one (never use a used dryer - you're just asking for grief there), and repeat the evacuate & recharge by weight cycle.
I lost all my refrigerant on the first refill. Then we ran two types of treatment (one for reconditioning the seals) that came with the kit, through the system and they worked. Blowing ice cold so far! (so far).
If there is too much refrigerant in the system How can I take some out? Is there a can that I can connect to so it doesn't go in the atmosphere?
Unfortunately without a machine that evacuates/recycles the refrigerant, there's no way to do this job without venting it to the atmosphere...
Don't tell the EPA that I told you this, and all the tree hugger's can stop reading now, but here's a safe procedure for a DIY mechanic equipped with a manifold gauge set to vent refrigerant to the atmosphere:
Since there's no easy way to measure & know how much refrigerant needs to come out of an overcharged system, the plan is to basically bleed ALL of the gas out, then evacuate the system with a vacuum pump, and then recharge it by weight. For the evacuation part, you'll need to get your hands on a good vacuum pump that can pull down to at least 29~30 inHg. Auto parts retailers like Advance, AutoZone, etc. typically have these on their rent/borrow a tool programs.
Before starting, wear your eye protection and gloves - freon on skin can give you instant frostbite.
1. With the car not running and cooled down, hook up your manifold gauge set to the H & L fittings, both valve wheels closed - at this point with it hooked up you'll be measuring the static pressure on both sides. The yellow hose connects to nothing on the end that normally hooks up to your refrigerant can, but you'll put a white paper towel over the open end as a means of checking to ensure you're not venting too much refrigerant lube out along with the gas - you only want gas to come out (see next step). Use a rubber band or something to fix the paper towel to the end of the hose so it stays put, and place the end on the ground where you can see it for the next step.
2. Crack open the L side valve wheel VERY SLIGHTLY - it should just be barely cracked open - while you're watching that paper towel covered yellow hose. Normally if you have a decent set of manifold gauges, when you crack it open ever so slightly, just the gas will hiss out of the yellow hose with very little to no oil escaping which is what you're shooting for. A little bit of oil coming out with the gas is OK, but you don't want it to be wet enough to soak & saturate the paper towel thru. If that happens, close the valve up, and try to SLOWLY crack it open again.
3. Now just watch the gauges. Both L/H sides should be slowly headed towards zero psi. If progress is slowing to a crawl, you can crack open the H side valve wheel too, basically repeating step #2 for the H side - throttle the valves so gas flows out with minimal oil loss (recall the paper towel). If you did it right, it will take roughly 15 ~ 30 minutes or more to reach zero psi on both H/L sides.
4. When both sides are at zero psi, you've got MOST of the refrigerant gas out. There will always be some small amount of left in there - that's another reason why you need to evacuate with the vacuum pump after this step, but almost all of the refrigerant lube should still be in there, which is the goal.
At this point, you can go back to a shop and have them evacuate it and charge it by weight. Or you can get a vacuum pump, a few cans of R134A and try to DIY charge by weight.
Unfortunately without a machine that evacuates/recycles the refrigerant, there's no way to do this job without venting it to the atmosphere...
Don't tell the EPA that I told you this, and all the tree hugger's can stop reading now, but here's a safe procedure for a DIY mechanic equipped with a manifold gauge set to vent refrigerant to the atmosphere:
Since there's no easy way to measure & know how much refrigerant needs to come out of an overcharged system, the plan is to basically bleed ALL of the gas out, then evacuate the system with a vacuum pump, and then recharge it by weight. For the evacuation part, you'll need to get your hands on a good vacuum pump that can pull down to at least 29~30 inHg. Auto parts retailers like Advance, AutoZone, etc. typically have these on their rent/borrow a tool programs.
Before starting, wear your eye protection and gloves - freon on skin can give you instant frostbite.
1. With the car not running and cooled down, hook up your manifold gauge set to the H & L fittings, both valve wheels closed - at this point with it hooked up you'll be measuring the static pressure on both sides. The yellow hose connects to nothing on the end that normally hooks up to your refrigerant can, but you'll put a white paper towel over the open end as a means of checking to ensure you're not venting too much refrigerant lube out along with the gas - you only want gas to come out (see next step). Use a rubber band or something to fix the paper towel to the end of the hose so it stays put, and place the end on the ground where you can see it for the next step.
2. Crack open the L side valve wheel VERY SLIGHTLY - it should just be barely cracked open - while you're watching that paper towel covered yellow hose. Normally if you have a decent set of manifold gauges, when you crack it open ever so slightly, just the gas will hiss out of the yellow hose with very little to no oil escaping which is what you're shooting for. A little bit of oil coming out with the gas is OK, but you don't want it to be wet enough to soak & saturate the paper towel thru. If that happens, close the valve up, and try to SLOWLY crack it open again.
3. Now just watch the gauges. Both L/H sides should be slowly headed towards zero psi. If progress is slowing to a crawl, you can crack open the H side valve wheel too, basically repeating step #2 for the H side - throttle the valves so gas flows out with minimal oil loss (recall the paper towel). If you did it right, it will take roughly 15 ~ 30 minutes or more to reach zero psi on both H/L sides.
4. When both sides are at zero psi, you've got MOST of the refrigerant gas out. There will always be some small amount of left in there - that's another reason why you need to evacuate with the vacuum pump after this step, but almost all of the refrigerant lube should still be in there, which is the goal.
At this point, you can go back to a shop and have them evacuate it and charge it by weight. Or you can get a vacuum pump, a few cans of R134A and try to DIY charge by weight.
Wow great play by play....thanks for the guidence. Seems like I'm going to have to wait for the guy who originally did the work. I already paid him handsomely to get this AC up and running. So I would hate to now go and pay someone else. The unfortunate part is that I have to wait until he is back in town. August 🤦
I thought it would be something I can quickly correct with minimal cost.
If you still need help with this let me know. I am local (Austin) and actually already helped another forum member get working AC in his FD, and recently finally fixed my own system to run the original R12. I have gauges, vacuum pumps and all the tools you'd need. Just shoot me a message
So I finally had the system checked and it seems that the freon was overfilled. We had to trouble shoot for almost 2 hrs and discovered that the system worked better with around 1lb of freon. But because it was so damm hot outside we weren't getting temps lower than 50-50 deg.
With spraying water on the condesor the temp started going down further to about 41. Much better!
What a difference have a in this weather.. Lol
I did notice on my ride home the compressor wasn't turn on and off but the water temps started going up super high, like 225 F. When on the highway the temps go back down and with the AC off there is no issue with climbing temps even at 100+ ambient temps. I stay around 190ish.
So the question I have is this the result of poor flow to the condenser at low speeds?
For me the AC Condenser is the close to the radiator. Thoughts?
Now the dual spal fans are pulling. Would an additional fan on the condenser side (pushing) be beneficial?
06-26-23, 06:52 PM
