Mother of all wierd idle problems.
#1
Mother of all wierd idle problems.
Got a 91 vert in my garage, that has a wonderful tendency to die when the AC is turned on. Now, before you say "remove your AC", its not my car! Here is a list of things that have been replaced/adjusted.
BAC-Replaced
ECU-Replaced with a Mazda Reman
ACV-Replaced
Water Thermosensor-Replaced
IAT-replaced
TB-replaced
TPS-replaced
Cats-replaced
5thGEAR/Neutral-replaced
Compression tested=good
Coil packs/timing checked
Now here is the deal. No matter what I do, no matter whats replaced, whenever the AC is turned on, the car dies. Only when its warm.
Any ideas?
Thanks in advance!
Jarrett
BAC-Replaced
ECU-Replaced with a Mazda Reman
ACV-Replaced
Water Thermosensor-Replaced
IAT-replaced
TB-replaced
TPS-replaced
Cats-replaced
5thGEAR/Neutral-replaced
Compression tested=good
Coil packs/timing checked
Now here is the deal. No matter what I do, no matter whats replaced, whenever the AC is turned on, the car dies. Only when its warm.
Any ideas?
Thanks in advance!
Jarrett
#2
Former Moderator. RIP Icemark.
First thing that comes to mind for me is a bad connection at the BAC.
Do any other electrical things cause the same problem (like the defroster or headlights/brake lights at idle).
Do any other electrical things cause the same problem (like the defroster or headlights/brake lights at idle).
#3
rawr
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when its turned on something is supposed to raise the idle, so something isnt working, dont know what it is though lol guess that makes this a worthless post, but ill see if i can figure it out in a min and repost
#4
Originally posted by Icemark
First thing that comes to mind for me is a bad connection at the BAC.
Do any other electrical things cause the same problem (like the defroster or headlights/brake lights at idle).
First thing that comes to mind for me is a bad connection at the BAC.
Do any other electrical things cause the same problem (like the defroster or headlights/brake lights at idle).
Nothing else causes the car to die.
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#9
Former Moderator. RIP Icemark.
Originally posted by J-Rat
Not quite sure what that will prove, but I can try it.
Not quite sure what that will prove, but I can try it.
The only reason that I ask is that if other electrical devices are not causing the problem, then that rules out the ECU and BAC.
Since you replaced a bunch of other things, I would next be looking at mechanical reasons rather than electrical.
#10
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before I start, I am more familiar with the s4, but here it goes anyway
You can look at the voltage at the bac before and after you turn AC on
The DC voltage should go down (this assumes the BAC behaves the same as on a s4), like from 11V to 10.5V.
If this happens, then the ECU is giving proper signal to the BAC.
If this does not happen, then either the ECU is not giving proper signal or the ECU does not receive input that AC has been turned on (from the AC switch).
IF you have PS steering, you can look at what happens when you turn the wheels. The BAC should react similarly to when the AC is turned on.
If everything checks out, then I would follow Mark's advice and look at the AC compressor (it may have a bad bearing or something causing to much stress on engine and causing stall).
Again, this is s4 behavior but s5 should behave same (I think).
Hugues -
You can look at the voltage at the bac before and after you turn AC on
The DC voltage should go down (this assumes the BAC behaves the same as on a s4), like from 11V to 10.5V.
If this happens, then the ECU is giving proper signal to the BAC.
If this does not happen, then either the ECU is not giving proper signal or the ECU does not receive input that AC has been turned on (from the AC switch).
IF you have PS steering, you can look at what happens when you turn the wheels. The BAC should react similarly to when the AC is turned on.
If everything checks out, then I would follow Mark's advice and look at the AC compressor (it may have a bad bearing or something causing to much stress on engine and causing stall).
Again, this is s4 behavior but s5 should behave same (I think).
Hugues -
#11
Originally posted by Icemark
If the problem is the compressor (such as it is internally damaged) it could cause the engine to die as well.
The only reason that I ask is that if other electrical devices are not causing the problem, then that rules out the ECU and BAC.
Since you replaced a bunch of other things, I would next be looking at mechanical reasons rather than electrical.
If the problem is the compressor (such as it is internally damaged) it could cause the engine to die as well.
The only reason that I ask is that if other electrical devices are not causing the problem, then that rules out the ECU and BAC.
Since you replaced a bunch of other things, I would next be looking at mechanical reasons rather than electrical.
hughes, I tested the BAC using the Paul Soaks method, And everything is good. But thanks for the suggestion.
Jarrett
#12
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If the compressor's failed internally and much harder to turn than it should be it would probably cause what you describe. With the ignition off you should be able to freely turn the center part of the compressor's clutch. If it's tight or locked that'll be the problem.
#15
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Originally posted by SaabGuy
Try turning it by hand with the clutch engaged.
Try turning it by hand with the clutch engaged.
#17
Rotary Freak
If you over filled the system then it will not get cold due to the compressor stressing out badly (therefore stalling motor). Compressor should not make any wierd noises other than clutch engaging and disengaging.
For like 6 months I thought my compressor was shot. Somone suggested I start dumping the freon out of it (r134 converted). After venting for almost 10 minutes, the A/C worked colder than it had ever. Before it was stalling the car at idle and sounded like a mac truck when cruising.
For like 6 months I thought my compressor was shot. Somone suggested I start dumping the freon out of it (r134 converted). After venting for almost 10 minutes, the A/C worked colder than it had ever. Before it was stalling the car at idle and sounded like a mac truck when cruising.
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