Shegs

so I recently bought this Quattro knowing it had a few problems, but looking forward to the ride if I could get it reliable.

most notably: it drives for about 5 miles and the engine just shuts off after about 5 miles. It happens when the engine hits about 100 degrees C and won't turn over until it cools.

Ive taken it in for a diagnostic and they said there were a number of problems (as I expected with the price) but it was probably the fuel pressure causing it. and that replacing the fuel pressure regulator and fuel pump should be priority one.

I bought a fuel pressure regulator and am using ALLDATADIY.com for a reference guide but am worried about the difficulty. it looks easy enough to replace but difficult to get to? is it easy enough to get to it?

how difficult is it to get to the fuel pump? I know it's in the tank but is there trunk access or do I need to get the car to a mechanic that can lift it?

I'm not the most experienced with working on automobiles, but I am a very technical person that shouldn't have any problem with this repair once I get going.

Kneale Brownson

Your problem is the engine speed sensor, one of two mounted behind an ineffective heat shield hidden in the driver side exhaust manifold piping.

The sensors overheat and stop sending the signals the engine control unit requires to operate the engine. If it was the engine timing sensor, located next to the speed sensor, it would permit the engine to run after a cold start but not allow a hot restart.

The V8 sensors are ridiculously expensive, but similar sensors for the 5000, 200 and A4 will work and are much cheaper on ebay. You only have to be careful that the longer wires on the cheaper sensors are tied up so they can't hit the exhaust piping and get burned. All these sensors are the same except for the colors of their wires.

The sensors and their heat shield are held in place by 10mm bolts.

Shegs

http://www.partsgeek.com/catalog/199...ce_sensor.html

not too bad, I'll look for cheaper ones. I'm also assuming that it's the RPM sensor that I'm wanting to replace?

Thanks

Kneale Brownson

You can buy two of the 5000/100/200 versions (longer wires) for the price of one of those Parts Geek V8 versions: http://tinyurl.com/buo88rz

Shegs

so then this one should be fine too? looks like it has a smaller cable.

http://www.ebay.com/itm/Audi-90-100-...#ht_6677wt_952

Shegs

alright I got them on amazon.
I'll let you know if it fixed the problem.

Thanks

Kneale Brownson

Since you already have the fuel pressure regulator, it's a good idea to replace the one that's there. There have been reports of them failing, resulting in flooding a cylinder with fuel and hydrolocking the engine. It's under the plastic engine cover. A screw on fitting, a hose clamp and just pull it up.

Shegs

I did some work yesterday, testing the waters on my own.

changed the hood support hydraulics
and the fuel pressure regulator

still waiting on one of the two sensors to arrive before I jack the car up and try my go at that.

Kneale Brownson

Some folks say they can get to the sensors from above. I have short, fat arms and had to get to the heat shield bolts from below. I used a 10mm gear wrench taped to a longer boxend wrench. The guys who could do this from above reported using 1/4" drive stuff. I had to remove the air cleaner and its housing to get to the connectors for the sensor wires.

Shegs

I don't know where I went wrong, but I couldn't find them for the life of me... I don't suppose you're in the San Jose bay area and free in the next few days?? :P