Where you live, I would forgo the A/C


Use to live in Colo Springs... had no A/C and survived. It was the Winters you had to watch out for.

 

Ended up purchasing a rubuilt A/C compressor from Discount A/C.com and found the price fair and the service good. Tight fit down there, especially the H/P and L/P connectors, but it's in and wonderfully quiet. I've yet to recharge the unit 'cause as Jim points out, it's not exactly swelteringly hot up here at 8,000'!
And now the boy's '97 A4 has developed an intermittent idle problem in that it's quitting on him periodically while at idle and then it's a bit hard to start. I'm suspecting the idle/air control unit but would welcome any thoughts/theories you all might have. Looks pricey so I'd also welcome any vendor ideas IF we all agree that this is likely the culprit. The car runs great all the other times/speeds and there's no Check Engine Light showing, for some reason. . .
I await word from my fellow Audiphiles. . .

 

Glad you got it going again.. even though its not as hot there as here, It can get uncomfortable on some days.

As for your boys problem..: ICM (Ignition Control module), Coil, Fuel Pump, MAF, Temp sensor.. The 'hard to restart' could be a clue for the temp sensor (too hot/cold leading to a too rich/lean mixture). The ICM usually shows with misfires first, but has been know to just 'die' when warm.. wait a bit and it works fine. Same with the coils.

I have personally had the ICM, fuel pump, and temp sensor problems.. Not on this car however.

 

You mentioned "idle", so I risk to go on a limb here, but you can take out the Idle Control Module (Valve) and clean it. MAF Sensor Cleaner works excelent on it. Maybe it is clogged.
At the same time (since you're pretty much "there") it may also be a good idea to pull out the throttle body and clean the butterfly flaps.
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As far as my compressor I'll try to shoot a charge with oil - I just noticed the other day that the fill port is right in the top corner (passenger side) of the cooler. Maybe that will cure the noise.

 

If you have no Check engine light, start by looking for a vacuum leak. The symptoms point there.

 

Howdy to all!
Well, I now have temporary possession of the A4 to more thoroughly diagnose and repair. By report, it has continued to intermittently stall at idle, which I have now also observed. Simply parked and while idling smoothly, it'll simply quit without warning and with no other signs. I ram a computer check and no codes are indicated. Thought I'd check/clean the MAF, the Throttle Body and then Throttle Position Sensor and the Idle Control Valve. I've got my wife's A6, 2.8, the exact same engine so may switch out components as a means of ruling in or ruling out problems.

I also have been shocked to discover the BRAND NEW front tires (new full set just 3 months ago) are shot!!!!! Both tires, outside edges, are bald and the kid didn't have the presence of mind to notice! Guess I'd better get it in for alignment, eh???? Pretty dumb but I've never seen tires wear so fast. The rears are still brand new- Michelin Pilots My bad. . .

Also have an intermittent clicking at the right rear and suspect either a CV or hub bearing. Ah, such fun! It's a fine running maching otherwise- honest!

Stand by for news.

 

Okay, I'm battling Murphy with the diagnostics on this car. The myriad vacuum hoses were, in fact, pretty ratty, hard, cracked and rotting. So, I replaced them all with fresh stuff but sadly, it did not solve the intermittent stalling problem. So, I pulled the IAC, inspected it, found it clean and energized it. It seems to operate smoothly so I fear that isn't the problem either. Next, I'll thoroughly clean the MAF then, if that doesn't resolve the problem, I'll pull the TPS and check it out. In the event that none of these diagnostics work, I'm going to be forced to look at the black box! Stand by. . .

 

Greetings Fellow Audiphiles
Okay, I've checked the IAC and all appears good. I've now pulled the TB and found it pretty carboned up, so it got a thorough cleaning. While off, I bench tested the TPS both incoming signal/voltage and resistance and all seems within normal parameters. I'm now reinstalling these units and will turn my attention to the MAS, giving it a thorough cleaning. If all this fails, I guess I'm forced to examine the ECU, which I'm not at all excited about since if it is faulty, replacement is quite pricey, I suspect. Stand by. . .

 

Hmm... you pretty much went through it all with the exception of fuel pump pressure and the Ignition Control Module.. unless you just didnt list them?

 

Hey Jim et al.!
Well, got it buttoned up, test drove it, had no problems whatsoever. Got home, parked it idling, took the dogs for a 10 minute walk up our road, returned to hearing it still running and, I kid you not, got to the front end of the car and it quit!!!!! So, all the system checks I've done have not solved the problem so next, the ICM. Jim, fuel pressure theory question: Wouldn't a fuel pressure problem, dying fuel pump, fail at any/all speeds? Seems to me fuel pumps either fail catastrophically or intermittently at all engine speeds. This problem is ONLY at idle and the car starts right back up without a hiccup. Your thoughts?
And any tips on testing the ICM? No codes are showing still. . .
Man, the car runs sweetly otherwise- good, smooth power, no surging, nothing!
We'll get it- persistence and perserverence