Sudden shut-down issues, no codes thrown
 

I've made several other posts in regard to this issue, but I'm making one final plea for any direction or experience with this issue.

1997 A8, 4.2l

The car runs for anywhere between 2-15 minutes before it shuts down. After this shut down, the car won't start for roughly 10 minutes, then starts without issue. Repeat.

The car's ECU was recently replaced, new fuel pump, and new temp sender circuit (all while trying to chase down the issue).

The car's not throwing any codes.

The current ECU is supposed to be off of a low-mileage '97 4.2. It has been suggested that the ECU might not match the particular engine correctly. It has also been suggested that the wiring harness may have a damaged or shorted wire that heats up, causes the shut down, and won't allow the car to start again until it cools.

These issues are stemming from the garage having crossed cables during a jump. The ECU was fried, and apparently some other component in the electrical system was also affected.

RE: Sudden shut-down issues, no codes thrown
 

Replace both of the crank sensors, they are known faulty parts in the D2 A8. One is used to start the vehicle and the other one is used to keep the engine running. IMO that design was overkill and it made it really hard to diagnose when it faulted because it usually never threw a fault code for either sensor. Just replace them both.
I believe they are abour $100 a piece.

RE: Sudden shut-down issues, no codes thrown
 

Parts are ordered. I'll repost after the install.

RE: Sudden shut-down issues, no codes thrown
 

Do you have the parts numbers for the crank sensors? The shop was only able to find one crank sensor for order.

RE: Sudden shut-down issues, no codes thrown
 

Well, replaced the crank sensor a few weeks ago, ended up driving it a few days fine just to see how things went, and then the damn problem started again. The fuel pump was making a loud whirring noise, so the shop swapped it out...AGAIN...and found that the pump itself was fine. So, they ended up replacing the throttle body housing and the car is FINALLY THROWING CODES! They're tracking down the codes as of right now, so hopefully this will be fixed soon. We're pushing 5 months without the car in my possession.

I'd like to takea final vote on this.... I'm planning on selling the car once I get it back. At this point, I can't tell if I've just had the perfect storm of A8 problems and it was a tough first year but now I'll have 100,000 miles of good service, or if I just need to bail out on this thing. Here's a list of everything in chronological order:

All six control arms up front
rear rotors
Bad fan clutch, meaning replaced clutch, fan, and radiator
Bad fuel pump
replaced ECU (due to crossed wires when shop charged battery)
pads all around
new spark plugs
throttle body housing
crank sensor
temp sender circuit

I feel as though I'm missing a couple. So, those of you with long-term D2 A8 experience, what do you say? Tough first year that will be worth it in the long run, or get the hell out while I still can?

RE: Sudden shut-down issues, no codes thrown
 

Sorry to hear about all your problems, me personally I think the A8 is the most problematic of all the audi's besides the allroad.
But most ofthe things onyour list is just maintance for an audi, the same would apply to a mercedes or BMW (which i have worked on both) so if the high cost of maintance isn't your thing, i would do away with german cars in general. SAAB is another vehcile maker you would want to stay away from.
If the shop gets the engine managment all sorted out and its working fine, i would drive it around for a while and see how you really feel about the car, because i love to drive the A8, more than any Japanese or American high end car.

RE: Sudden shut-down issues, no codes thrown
 

That's my conumdrum, I absolutely love the car. To be honest, I expected to have to deal with all of these problems, just not within one year. I really do think the car is worth the time and money, it's litterally the perfect car for my personality and needs, which is why I haven't bailed earlier. The big ones are all pretty explainable... control arms are normal for the car's mileage, the whole fan clutch/radiator fiasco was actually caused by a bad motor mount putting extra stress on the clutch (I didn't know there were radiators that could cost $650.00), which is basically one of those flukes that you'll get with any mid-to-high mileage car. I've done my research and I'm waiting for a transmission problem, though my tranny seems pretty solid and I barely even experience the gear-searching at 40ish mph.

I was expecting maintenance issues and always had the cash ready for them, but I suppose my question is this: should I be expecting three or four $1,200+ garage visits a year, or was it just a "perfect storm" year? I really appreciate your advice... I'll have a hard time letting go of the car because none of my other options compare to it at all.

RE: Sudden shut-down issues, no codes thrown
 

I know exactly how you feel, when i bought my 01 S4 in 2006 with 63,000 on the clock, everything went wrong with it in the first few months. Every common major problem that could go wrong with the S4 did with mine, everything from window regulators to torn cv boots. All in all i spend around $3,500 in repairs in six months, thats with doing all the wrenching myself, at the dealer it would have run around $6,000. Of course i had to do the timing belt and water pump combo at 80K as well. Now it has 99,000 miles on it and i haven't had a single problem with it yet (knocks on wood)

As for your A8, your problem is much the same. You have taken care of all the major problems except for the transmission. I recommend replacing the trans fluid and filter on all automatics from 80-100K miles. As long as you do that you most likely won't have any problems with your car from quite some time, and if you do, it most likely would be a minor repair. I would say that you wouln't have to pay more than $1,000 in repairs in the next 3 years, thats including the transmission service.

RE: Sudden shut-down issues, no codes thrown
 

Thanks for the advice. I'm going to give it some time and see how things go with the car. I'll you posted.