A/c Problem

2eyefishclaw · #1 10-03-2006, 03:51 PM

I am currently working on an 03 Isuzu Ascender once engine has reached operating temp, turn on a/c and engine dies
any info would be greatly appreciated

maxwedge · #2 10-03-2006, 04:27 PM

Try disconnecting the compressor clutch wire and see what happens.

rodeo02 · #3 10-03-2006, 04:35 PM

2eye!! Fancy meeting you here!

I know your 'fondness' for the general's vehicles.

If the compressor/clutch is good, dirty throttle bodies are common on the 4.2L I6. The throttle bodies are nearly identical to the 2000+ isuzu 3.2/3.5's, A good spray cleaning usually clears up a low or erratic idle. The 4.2's idle low to begin with & have no idle up switches anywhere that I am aware. Any idle up would have to be ECM prompted.

G/luck
Joel

2eyefishclaw · #4 10-03-2006, 05:40 PM

got it
found old PCM update for idle stability concern
reprogrammed PCM its all good now
oh I also did fail to mention it was an 03 with the 4.2 and I had already cleaned t-body

maxwedge · #5 10-03-2006, 07:43 PM

Just out of curiosity how did you update/reflash the pcm?

2eyefishclaw · #6 10-03-2006, 08:02 PM

I am a Tech at an Isuzu dealership

rodeo02 · #7 10-04-2006, 05:58 AM

Quote:

Originally Posted by 2eyefishclaw

..reprogrammed PCM its all good now..

Good deal. The thing that always puzzled me about PCM software updates: A truck can idle fine for ~3yrs and all of a sudden have a stalling concern where a software patch is the fix?

What changes other than the engine being more 'broke-in'?

Joel

2eyefishclaw · #8 10-04-2006, 11:41 AM

dont know man this one has 140,00 miles on it

2eyefishclaw · #9 10-04-2006, 11:41 AM

dont know man this one has 140,00 miles on it

rodeo02 · #10 10-04-2006, 12:05 PM

Quote:

Originally Posted by 2eyefishclaw

dont know man this one has 140,00 miles on it

140K miles?? WOW! That thing has never cooled off. The theory on another board is- parts of the software can get scrambled by static, etc.. causing concerns that require a reflash. Sounds ok to me I guess.

Joel

2eyefishclaw · #11 10-04-2006, 06:01 PM

gremlins and aliens screwing with programming while owners are sleeping

16th hippy · #12 10-15-2006, 04:51 PM

and it also could be just an updated adaptive strategy for the pcm to open the IAC a little longer on each pulse, or those(most) with TAC to open the throttle blade a little(just an opinion to throw into the mix). is why i tend to reset the fuel trim and TAC data after doing a TB cleaning.

and to open another can of worms, if programs are being scrambled by static, then wouldn't there be another problem with the vehicle that needs to be taken care of NOW before we fry say the BCM or PCM?

not trying to flame,pounce, or anything of the like. just interested in taking this conversation further for the sake of learning.

rodeo02 · #13 10-15-2006, 11:11 PM

Quote:

Originally Posted by 16th hippy

...if programs are being scrambled by static, then wouldn't there be another problem with the vehicle that needs to be taken care of...

Yep, I would think so. The way programming, logic, etc.. ties together, you'd think the whole 'module' either works or it doesn't. Maybe a software update (with newer software) better handles a well broken-in engine? Just a guess.

Joel

16th hippy · #14 10-16-2006, 10:28 PM

stands to reason, but the vehicle should have the adaptive strategy built in from the factory to handle aging components....notice i say should...lol. Then again, cars can be fickle machines.

Auto_fan · #15 05-29-2007, 07:28 AM

guys i have this problem

i changed my car battery, since then whenever we switch A/C the engine stalls then power off

can i fix it myself? its over 100,000 miles and the dealer will ensure ripping off my pocket

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