Car dies with AC Running
Thread Starter
Drifting
Joined: May 2008
Posts: 1,517
Likes: 319
From: Hewitt TX
Car dies with AC Running
So driving home from work today I kick on the AC. The next light I come to I push n the clutch and the car just dies. I restart the car and it is searching for RPM. I get it going then at the next light it dies again as soon as I push in the clutch. My car has a cam and has been tuned but it has never really done this before. I have noticed that the compressor is making a rattling noise at times and that I can not easily spin the clutch on the compressor by hand. Any ideas?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I seriously doubt that the compressor has anything to do with the issue BUT,,the change in fuel and timing that the AC "RUN" signal that the PCM See's is causing your issue to surface. Its a normal signal and is used to stabilize the idle when the compressor load drops engine speed.
Before you get too deep in to HVAC stuff,,check for vacuum leaks, dirty MAF, and air leaks between the MAF and Throttle Body.
If you have access to HP Tuners, EFI Live, DTC Scanner that has live scanning capability or a TECH II, check the Long Term Fuel Trims and see where there at before and during the issue.
If all the above are not at fault, see if the PCM is actually seeing the AC ON signal to change the idle tables. If all the above things are fine, there are idle tables that can be adjusted using EFI Live or HP Tuners that will resolve this issue.
See if this happens also: With the AC OFF, and the car idling turn the steering wheel quickly right and left lock to lock and see if it causes the idle to whack out. The same sort of signal is sent to the PCM when the steering assist pump pressure rises. The PCM tries to keep the idle speed constant and adjust timing and fuel to compensate.
Before you get too deep in to HVAC stuff,,check for vacuum leaks, dirty MAF, and air leaks between the MAF and Throttle Body.
If you have access to HP Tuners, EFI Live, DTC Scanner that has live scanning capability or a TECH II, check the Long Term Fuel Trims and see where there at before and during the issue.
If all the above are not at fault, see if the PCM is actually seeing the AC ON signal to change the idle tables. If all the above things are fine, there are idle tables that can be adjusted using EFI Live or HP Tuners that will resolve this issue.
See if this happens also: With the AC OFF, and the car idling turn the steering wheel quickly right and left lock to lock and see if it causes the idle to whack out. The same sort of signal is sent to the PCM when the steering assist pump pressure rises. The PCM tries to keep the idle speed constant and adjust timing and fuel to compensate.
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Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
For your AC Noise issue, have someone check your AC System high and low side operating pressures.
If the system pressures are excessively LOW or HIGH, you will have abnormal noises. My buddy WARLOCK just had a strange noise that he could hear inside the car and at the compressor. It was caused by lower than normal system pressures. He had the system properly charged and the noises went away.
Theres a chart in the service manual that details the correct pressures with respect to outside temps, humidity and engine operating speeds. Without that chart, correct pressures can NOT be predicted.
BC
BC
If the system pressures are excessively LOW or HIGH, you will have abnormal noises. My buddy WARLOCK just had a strange noise that he could hear inside the car and at the compressor. It was caused by lower than normal system pressures. He had the system properly charged and the noises went away.
Theres a chart in the service manual that details the correct pressures with respect to outside temps, humidity and engine operating speeds. Without that chart, correct pressures can NOT be predicted.
BC
BC
Thread Starter
Drifting
Joined: May 2008
Posts: 1,517
Likes: 319
From: Hewitt TX
I tried again today and same result although both days now I have noticed that my compressor did not turn on right away. I had to turn it off and on a few times before it actually kicked on then it was making a knocking/rattling sound. Also, I did change spark plugs this last weekend. Is there anything I could have messed up while doing that? I am almost afraid to drive it.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Have the AC system pressuer checked ASAP. Thats the only way that were going to be able to lead guide and direct properly.
Also read and post your DTCs All of them
BC
BC
Also read and post your DTCs All of them
BC
BC
Thread Starter
Drifting
Joined: May 2008
Posts: 1,517
Likes: 319
From: Hewitt TX
There are currently no HVAC Codes but I do periodically get a P1637 because I get the dreaded charge system fault sometimes and it is like a witch hunt tryin to figure that out. I have heard that is the compressor is low on freon that it will become very vocal. Is this true?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Depends...... If its REALLLLY low,,,it wont run. 
If its a little low, it can make noise. If its HIGH or plugged up,,,YEA,,,,it will make lots of racket. So, like I said. Install a manifold an read the LOW and HIGH side pressures. Make SURE that you note and display the temp and humidity during the test.
Post the pressures
BC
If its a little low, it can make noise. If its HIGH or plugged up,,,YEA,,,,it will make lots of racket. So, like I said. Install a manifold an read the LOW and HIGH side pressures. Make SURE that you note and display the temp and humidity during the test.Post the pressures
BC
Thread Starter
Drifting
Joined: May 2008
Posts: 1,517
Likes: 319
From: Hewitt TX
ok Bill, here is what I got. I went down and bought a pressure gauge.
Low side 125
High Side 150.
Temp: 84
Humidity: 46%
On the gauge the high side said it needed service and the low side was in the warning zone.
does this mean I have a bad compressor or a plugged line?
Also, there was alot of black oily substance that came out of the high side as I disconnected.
Brent!
Low side 125
High Side 150.
Temp: 84
Humidity: 46%
On the gauge the high side said it needed service and the low side was in the warning zone.
does this mean I have a bad compressor or a plugged line?
Also, there was alot of black oily substance that came out of the high side as I disconnected.
Brent!
Thread Starter
Drifting
Joined: May 2008
Posts: 1,517
Likes: 319
From: Hewitt TX
Those pressures were with the system running. with the system off they were like 130 low side and 125 ish high side. I am hoping I have a pplugged line or something because I really dont want to have to try to remove that compressor.
Tech Contributor
Joined: Jan 2007
Posts: 19,482
Likes: 1,173
From: Dyer, IN
Check your service manual in the A/C performance table. At 84 degrees F, 46% RH the low side pressure should be 29-33 psi, while the high side should be 141-189 psi....with air discharge temp of 48 degrees F.