A/c Problem

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

Try disconnecting the compressor clutch wire and see what happens.

2eye!! Fancy meeting you here!:cheers: I know your 'fondness' for the general's vehicles. :grinno: 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

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

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

I am a Tech at an Isuzu dealership

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

Joel

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

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

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

gremlins and aliens screwing with programming while owners are sleeping

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.

...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

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.

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 :(

fixed !

it costed me 100$ for:
1) fix three error codes in car: throttle setting, idle setting, and O2 level
2) also clean injectors (as they said) i don't know how they did it

now the car is smooth and A/C is so friendly with the engine.

That's good news. I would have said take it to Autozone and get a free scan - the codes would have gotten you to where you landed anyway. I dunno what part of the country you're in, but there's a lot of plain greasy gasoline being sold right now. Refiners are kicking over to summer blends. I've had good luck with Shell as far as the injectors running clean. I know you'll hear that gas is gas, but I can tell the diff between a tank of Shell reg and Citgo.

on those there is no idle setting or throttle setting....they probably sold you the fuel imjection service cause it comes with a throttle body cleaning. the throttle is electronically controlled and if the blade gets dirty it can cause all kinds of problems. Glas you got it fixed good though.

Cars CAN be fickle, but look at the conditions that the electronics have to operate in! Almost constant vibration, temperature extremes, and occasionally being soaking wet. Granted, engineers get paid well to make sure the electronics can hadle all these extremes, but it's surprising to me that vehicles don't experience MORE problems than they do.

Same here. It's easy enough to belly-ache about a defect and project the irritation to the vehicle line. GM's stuff is no worse, no better than Mercedes, BMW, Honda or Toyota. I wish we could get back to the days when our vehicles weren't so electronics-dependent or else that, if we're going to run everything via programmed chipsets, we were still building our own, using the best materials & labor right here in the USA. Remember Compaq computers in the '80's? Built in Houston, TX, enough gold in that hand-soldered motherboard to make a chain of bling. Compare any Third World manufactured PC today. It's all commodity junk. The vehicle mfrs - all of 'em - don't have any choice but to follow suit, or go broke in the U.S. market.