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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Honda
Satisfied Customers: 47337
Experience:  16 years of experience
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Crv: thanks and responding. After the compressor

Customer Question

Hi thanks for reading and responding. After the compressor coil had an "open" I changed the AC compressor complete with clutch. Everything was good @ idle for cooling, but at higher RPM's the compressor would cut in and out. With the new compressor I also changed the clutch relay, desiccant bag, & screen. When the compressor cuts out cooling is ok, about a 20 degree F drop. The high will go up to 300 PSI and low will go down to about 15 psi. when the compressor cuts in it is very noticeable and feels like a lot of load on the engine. so I evacuated and recharged the the system (R134A) to confirm charge. Same thing. Changed TXV, checked the cabin filter has (10000 mi & looked good) , same problem. Cooling fans have always been on when stationary, tried the shop fan also for testing with the gauges. We have tried driving with out the grill and it was no better. Checked for cold spots in high side line, low side collects condensation but has never been frosty. Checked evaporator sensor, and is with in spec 28 000 ohms in ice water. Also has good air flow from the vents. Thank you for you help. Please ask some questions. Jason
Submitted: 1 year ago.
Category: Honda
Expert:  Chris (aka-Moose) replied 1 year ago.
Can you give me the high and low side pressures at 1500 rpms, blower speed 2, on recirculated air?
Customer: replied 1 year ago.
Hi thanks for reading. To get those readings, I will have to go to work. I did get pressures at 2500-3000 rpm ( the speed at wich it would act up) Ac would cut out at about 15 psi low side and high side at 280. It will cut in 10-15 seconds later, the high side will go to 300 psi and cut out when low side gets to about 15psi. Pressures at idle seemed ok but I don't remember them. The pressure @ 1100-1200 rpm were within the honda "Air conditioning system performance test" specs, and I don't think it cut out at that low RPM.
Yesturday was cooler, had rained and more humidity, High 70'sF and it seemed to work ok with the windows open driving from town.
I will get get back to you with more data. Thanks Jason
Customer: replied 1 year ago.
Ps please be patient, I am only a diesel engine mecanic.
Expert:  Chris (aka-Moose) replied 1 year ago.
Being the pressure was fine at idle and 1200, there is no need to check it at 1500 for me.The pressure switches are working right being they are cutting the compressor off when the pressures get to high and to low. So that eans the reason your compressor is cutting off is because your requesting just enough load from the engine that the computer thinks its best to kill the power to the compressor and give you more engine power. So that would be a normal scenario. You want a excellent 5 star answer & I would like to be rated the same for providing it. Consider I don't know your skill level & I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies. Try your best to respond with good detail so I can do the same. I normally log in at 3pm and work late. A rating is required. Your rating me, what I type. I am not an employee of this website, nor have control over the fees or the time it took to get a response. If you rate negative or not at all you still paid, but I get nothing. I want you pleased with me and my efforts, so let me know if your experience here has come up short.Thanks Chris
Customer: replied 1 year ago.
So that's it?, it's a normal scenario for ac to cycle in and out and not cool ( the system has one pressure switch, on the high side; spec of 28psi & 455psi). Did I miss a switch?, load sensor? You will have to work a little harder than this, it has stumped me for 4 weeks.
Customer: replied 1 year ago.
And yes I know it seemed to work ok Friday, after I reinstalled the Evaporator temp sensor and it was cooler. Should I change the evap. temp. sensor?
Customer: replied 1 year ago.
(Cooler weather, with rain).
Expert:  Chris (aka-Moose) replied 1 year ago.
I was under the impression the it was still cooling and the compressor was cycling on and off at high rpm. Are you saying its just shuts off and no longer cools. How long and often are you keeping the vehicle above 3000 rpms?
Customer: replied 1 year ago.
Sorry what I did not originally say, after a sustained cruising speed, or high rpm (to simulate, our manifold gauges are damaged) cooling stops compressor starts cycling (I didn't ever leave it on or turn it back on at lower engine speeds). while cycling ( I think once every 10 secs) there would be no cooling.
At idle, 1200rpm ac will cool fine, @ normal cruising rpm (2800rpm) the AC will start to cut in and out with a very noticeable load on the engine. We never felt the compressor cycle before. Before I changed the TXV, my wife was driving (without me) it started doing this made a weird noise and a bad smell. two weeks ago night before our vacation I changed the TXV. still had the same symptoms (80 deg. F 9:30-10:00 pm). tomorrow morning ( hopefully) I will get a small temp gauge, put it in the same hole as the evap temp sensor hole. it will be interesting to see the temps with different blower settings. Given it has a txv temps and psi should not change much, right?
Customer: replied 1 year ago.
could not sleep, this is keeping me awake.
Customer: replied 1 year ago.
today Ac seems to be working fine. ( was less than 70 deg F & sunny, crv was like a green house, fan on low also had windows open) I went and got a temp gauge. min reading thru the evap sensor hole was 29.5'f max was 43.8'f... I will recheck later when it warms up & restrict condenser (too simulate the hot days when this started).
Expert:  Chris (aka-Moose) replied 1 year ago.
Can you duplicate this concern just reving the engine in park to this problem rpm?The AC should cut off under a high rpm or load but it should return back on when the load and rpm reduce. A cycling compressor is normal, but its should be cooling during this, if anything it should cool better at this speed from the extra air flow to cool the condenser.
Customer: replied 1 year ago.
Yes I did duplicate the same problem, cruising down the road while the car was stationary. I could only check the pressures with the charge evac machine. testing was done with the hood open, blower on high recirc, and condenser fans running. during testing I only checked the pressure once at 2800 rpm. I did not persist testing after the compressor cycled a couple times and reached 300psi. At that point I actually didn't check cooling. (when it cycles on the road I know it cooling is very poor).I know the ac will cut out (when @ 100% throttle) via a computer. Maybe there is a load value as well, but I have not heard of that.
I ordered a new evap temp sensor today. I am being optimistic that my testing of this sensor, bent the pins to make better contact. I will test pin tension when I change the sensor.
Expert:  Chris (aka-Moose) replied 1 year ago.
Let me know the results on the EVAP sensor, though i just can not see what high rpms has any effect on that. The ability for the compressor to create more and faster pressure at higher rpm is the issue, but we need to figure out why the system is not adapting and adjusting for that. I still can not tell if you can duplicate this just holding the throttle at 3000 rpms in park?
Customer: replied 1 year ago.
Yes I did duplicate the same problem while stationary, while maintaining 2800-3000 rpm. also tried adding large shop fan for cooling, which did not make a difference.
Expert:  Chris (aka-Moose) replied 1 year ago.
Stationary at this rpm, can you get me the high and low side max and min pressures as the compressor is cycling on and off?
Customer: replied 1 year ago.
I got a temp gauge yesterday morning and drove back with it in the same hole as the evap temp sensor. On low & med blower and temp on cold temp would run around 29.5-34 deg F. Ambient was only about 75deg F. operation was good. Tonight I got everything hotter by restricting air flow (ambient air temp in low 70's). Operation was good @ idle, ran at about 2800 rpm for about 2 min & compressor started cycling, the same as it did before (cooling dropped 5-10 deg F in one minute of testing). ( Previously the compressor cut out at 15 psi, the high would cut out @ about 280 psi. When the compressor would cut back in high pres would quickly go up to 300psi)...
So I checked the pin tension of plug the evap temp sensor was good. Installed new sensor. Retest, same operation; no better.
Cooling is still ok @ idle. Check operation just off idle, and found the compressor is cycling erratically, (similar to 2800 rpm).
To summarize when I seen the compressor cycle (and get poor cooling), the car has always been hot and of idle; Ac @ max setting/demand.
So far I have not seen any parameters at the max limit, when the system cycles erratically.
So what turning off the Compressor?
Is the coil getting an open?... when hot.
Can the compressor clutch not take the load?
Has the PCM mistaken part throttle for the time to cut the AC? (Poor fuel mileage was my next challenge)So I need to check power & amps to the coil, power to the relay.
How do I check the throttle and Pcm, for the full throttle cut out?
Thanks Jason
Ps I didn't really want to recheck the pressures as I didn't make time and the operation was the same.
Expert:  Chris (aka-Moose) replied 1 year ago.
I think I have gone as far I can not being in person. Would you like to get back on the waiting list in hopes another tech will pick this up.
Customer: replied 1 year ago.
Hi Chris, yes can you pass this to Kyle N? Thanks Jason
Expert:  Chris (aka-Moose) replied 1 year ago.
Opting out now.
Customer: replied 1 year ago.
Got it fixed. I don't need your services anymore. Thanks Jason
Customer: replied 1 year ago.
How com I can't close this, with a "bad rating"