Poorly V6

[SD1too]

Originally Posted by vitesse

What's your line of thought?

That a small leak will upset the fuelling until the lambda sensors take control by which time the expansion of the exhaust system will have sealed the leak.

This happens very quickly so you’ll need to support the car safely, start the engine and immediately run the palm of a hand close to, but not touching obviously, the joints in the exhaust system (including the sensor ports). If there’s a small leak you will feel it, but you have to act quickly.

Simon

[vitesse]

Thanks Simon, luckily I have a pit in the garage so I'll take a look (or feel). I have heard some popping in the exhaust when starting but rather think that's unburnt fuel.

Mike

[vitesse]

After 2 weeks on holiday I had time to try and get my daughter's car back on the road.

No exhaust leaks found but by the time I get the car running properly the exhaust is too hot to touch.

But, after buying a fuel pressure gauge it reads only 2 bar, and pressure drops almost immediately after switching off, no fuel leaked when I disconnected the gauge.

Out to try my own V6, fuel leaked when connecting the gauge even those it's not been used for a couple of hours. Fuel pressure almost 4 bar, switched engine off and pressure stays at 3.5.

So does this mean that the pump is defective, or the regulator on the fuel rail or both?

Regards

[SD1too]

Originally Posted by vitesse

So does this mean that the pump is defective, or the regulator on the fuel rail or both?

My immediate thought Mike is “fuel filter syndrome”.

Simon

[vitesse]

Thanks Simon but early type filter

Mike

[vitesse]

Opened up the pump inspection hatch to replace the 2001 pump with a 2002,and found the plumbing is different. But then noticed, at the bottom of the tank, a white platform with two bayonet connectors, and two loose hoses which should obviously be fitted on to the platform. A quick inspection of the empty tank of the 2002 donor, no white platform.

Drained the right side of the tank and lifted the pump out to inspect the fitting. Not much to do, refitted the bayonet connectors ensuring a good click, retested fuel pressure which now read almost 4 bar, car started immediately.

How those bayonet connectors had worked themselves loose is anyone’s guess. But I now know where to look if it’s an early car with low fuel pressure.

Thanks to all contributors.

[Vanbursta]

Originally Posted by Davethepaint

Yes a purchased an Audi 80 years ago .

Wow must of been an Audi 1, those Germans sure know how to build em!!