dermot

Hi,

Just a newbie question (I'm not used to cars with AC!). My 2000 T/A manual has been fine for last year or so... until this morning when the AC stopped blowing cold, suddenly. It's always been fine up to now, but I just discovered from this forum that:

1/ apparently the ecu disables the AC when you drive the car harder... but I <thought> that this would mean if you were e.g. doing 5000 rpm, whereas I've seen it said here that it should be disabled around 2500??? Is this really so?

2/
Apparently custom tunes (which mine has) can change or even disable this, possibly for the worse, thus leading to destroying the compressor...

...now I'm wondering if I've done this. I had innocently assumed (never assume!) that the ecu took care of all this and I could do what I liked to the car - it's got 4:10 gears and is often over 3000 rpm, even on the way to work every morning! - and the AC is ALWAYS on, since it's usually over 35C outside...

There's no check engine light etc., I'll check if the diablo that I have says anything later, the drive belt is still there anyway...

Any suggestions.... ???

Thanks, D.

mike171562

iTrader: (4)

I'm no A/C expert, but I would charge it up with Freon and if that didn't fix it, Check your fuses, check the compressor to make sure the clutch is engaging and the compressor is spinning like it should. My A/C shuts off only at WOT around 5000 + RPM's

2001NBMZ28

Check for any codes first, AC codes do not illiminate the SES. Don't know if predator reads 0530, 0645, 1546, etc.

fleetmgr

The first thing to check is if the A/C clutch is engaging. If you look at the compressor, does just the pulley spin, or does the pulley and the entire assemble inside the pulley spin? If you turn the A/C on can you hear the clutch "click"?

dermot

Thanks gentlemen, helpful as always, I'll check these things today..

kr

D.

dermot

Ok, the AC compressor spins/stops as expected, no codes in my Predator readout... also it blew cool for a short while today... I think it needs recharging... (I hope...)

kr

D.

fleetmgr

If it needs recharging, then it also has a leak somewhere that needs fixing.

Texhotrod593

iTrader: (7)

dont go into this problem blind! it could be quite possibly a 100 things and you could guess all day! I have said this before and will say this again... SYSTEM PRESSURES ARE A MUST!!!!! They tell the WHOLE story of what a a/c system does. If the pressures are fine at idle but the compressor cuts off when its revved then you can look into other things like tune, switches etc... But it really does sound like either high discharge pressures from a dirty condenser coil or a low refrigerant charge. As fltmngr said, if its low....ther IS some sort of leak that will need to be found and repaired. throw some gauges on it and let us know what kind of pressures you find! good luck

dermot

Sorry 4 long delay, been on holiday, without TA...

Ok, so I took it to be checked, they told me it has "zero pressure but no problem with freon quantity" and that this means I need a new compressor...

...I think they are right... Perhaps I did destroy it revving it high with the AC on full (all the time) oops...

Best to get one of those kits that replaces everything, right?

kr

D.

fleetmgr

There are only two ways for it to show zero pressure. 1. Their gage is messed up. 2. There is no refrigerant in the system.
Even with the engine off, there is still pressure everywhere in the system, and that pressure will correspond with ambient temperature assuming you didn't just shut it off 30 seconds ago.
Whoever checked it for you doesn't have a clue...in fact couldn't BUY a clue.

Texhotrod593

iTrader: (7)

fleetmngr>>>we have helped many people together on these ac issues! lol. some listen, some dont. i do however have a feeling he did in fact take it to a person knowing whats going on(still a little skeptical myself). I think maybe what the 'professional' person told him might have been more like "You have no DIFFERENT pressure between the suction side and high side". Now this is only a guess but being the OP dont know much about ac systems, he might of taking that quote as to meaning "the system has no pressure there for the compressor will need to be replaced". If the compressor is turning in fact but not pumping(maybe because of bad valves) then the compressor will need to be replaced. I thought it sounded a little funny too fleetmngr, but it took me about 30min to understand the possibility the OP didnt understand or quote the "professional" correctly.
That being said...To the OP, if the caompressor is being rplaced by a professional and licenced ac person you should have no worries about it being done properly or buying anything else for the replacement. If you do it yourself, you will need compressor, accumulator/drier, oil, refrigerant, possibly system flush, new gaskets, and a little elbow grease. Good luck and let us know if you need anymore pointers. I know fleetmngr and I can both help very well and i am certain there are others that can chip in.
--Joshua

fleetmgr

TexHotRod, you may well be right. However, after having seen first hand many horror stories with A/C systems from supposed professionals, you'll have to excuse me for being a cynic.

Texhotrod593

iTrader: (7)

Well I will just join you being a cynic! I have also seen first hand these horror stories you mentioned. You do however deserve a pat on the back for all the help you have given to tech members about their a/c systems...

dermot

Thanks guys!

In fact since the people I'm talking to don't have English as a 1st language (!) but it is very very bl**dy hot all the time (+44C) out here (Dubai). I suspect that they know what they are talking about, they for sure work on a hell of a lot of A/C - they just can't explain it to me clearly... I should have watched the gauges myself as well!

They advised me to replace: compressor, drier/acc, orifice tube, and belt for luck (its a bit cracked up).

Just as a bit more info: until I found out i shouldn't, I have habitually taken my manual car to 6000 rpm plus with the ac on max all the time. So I think I've destroyed the compressor (oops).

Think I'll order one of the kits of bits anyway!

-D

fleetmgr

At WOT, your compressor clutch automatically disengages (or at least it's supposed to) to prevent exactly what you describe. However, history shows that A/C compressors don't need much encouragement in order for them to expire.
Your explanation on the host nationals makes things MUCH clearer, and gives me a better feeling about what they are telling you. I've been stationed overseas before, and well understand what you're dealing with. What they advise is totally in line with a dead compressor...just make sure you flush the system, too. Without the flush, you'll have another dead compressor in short order.

Good Luck!

dermot

Sorry to come up with another....

...I now found someone who I trust (I think) to change all the AC bits for me, which I've now imported (comp/acc/orifice tube/seals), but they are warning me that sometimes flushing it is not enough, and you have to replace the rads as well (ok one of them isn't a rad but u know what i mean) because you can't get all the junk out by flushing, if it failed "badly" there will just be too many metal particles floating around etc.

Is that a reasonable statement?

They say they can tell once they start work and look at the compressor etc., which does sound sensible to me.

Thanks in advance...

-D

Arc00TA

iTrader: (17)

I'm getting ready to take mine to a shop for the same issue. FWIW, ECM shuts off the compressor clutch at 4600 rpm if I remember correctly. I can take a look at the stock M6 tune later and see.

I just need to get mine pressure checked and see if theres any refridgerant in there. If they say the compressor is crap, I'll just delete the A/C since its so damn expensive to fix. Not really an option in dubai though, been there a few times, definitely need A/C.