From Audi 100 to urS4 in a week

[UrS4boy]

Here it says "May Fit" the AAN

Also says

Pressure: 4 bar / 58 psi

OE PART NUMBER:
078133534
078133534A
078133534C

So will fit.

[hunker7]

078133534A was superceded to 078133534C in 1998 but both were 4 Bar fuel pressure regulators so, in theory, that is not the issue (but I said *theory*)

I should have it somewhere, I will put it back in and see what it does, worth trying.

Gutted about the ECU though, not a cheap thing to buy. Is there any way of determining what's wrong with it?

[hunker7]

Here it says "May Fit" the AAN

http://www.ebay.co.uk/itm/Bosch-OEM-...item27e922e534

I have a donor car now I can play around with while it's not a runner

If i remember right, it looked different to one one AAN when I swapped it, but pressure was the same so I chucked it in.

[Error404]

If you are getting 18mpg with a heavy right foot, then your foot ain't heavy enough pal

[hunker7]

If you are getting 18mpg with a heavy right foot, then your foot ain't heavy enough pal

Or I have one f0cking mint ride I will leave it in for now, and see what I average under normal driving.

[newsh]

Worth swapping for the one from the other car and see if it makes any difference.
Also check the vac line to the FPR is good and solid and not leaking, if it leaks then it will run lean on boost.

[hunker7]

Worth swapping for the one from the other car and see if it makes any difference.
Also check the vac line to the FPR is good and solid and not leaking, if it leaks then it will run lean on boost.

I am sure I have the old one somewhere in my parts box Good point about the vac line don't think I've checked that. fingers crossed

[newsh]

I think the AAN is like ABY and has a section of metal vac line so there are 2 short bits of rubber line and 4 clips. If the rubber line is original it is usually leaking..

[hunker7]

I think the AAN is like ABY and has a section of metal vac line so there are 2 short bits of rubber line and 4 clips. If the rubber line is original it is usually leaking..

I am quite sure it's still all original

What I noticed with the "grey S4" ECU is, it takes longer to boost.

[newsh]

Same thing applies with the vac line to the ECU, if it's original it may well be leaking, especially where it clamps at the ECU end

[UrS4boy]

Gutted about the ECU though, not a cheap thing to buy. Is there any way of determining what's wrong with it?

I have NO idea which ECU/which car you are talking about anymore.

You need to start a new thread for the grey 93 S4 avant. It is hard enough to try to help you with the red one without mixing comments about the grey one into the red one's thread. Seriously does our (mine at least) head(s) in.

[hunker7]

I have NO idea which ECU/which car you are talking about anymore.

You need to start a new thread for the grey 93 S4 avant. It is hard enough to try to help you with the red one without mixing comments about the grey one into the red one's thread. Seriously does our (mine at least) head(s) in.

OK, will start.

At the moment i fitted grey S4 ECU into my red one, and fuel economy has gone up considerably. Is there a way to determine what is wrong with the red one's ECU that the fuel economy is *****.

[hunker7]

Same thing applies with the vac line to the ECU, if it's original it may well be leaking, especially where it clamps at the ECU end

I've replaced vac line clip on that already

[newsh]

Has the red one's ECU ever been apart?

[newsh]

In my experience the ECU is hardly ever at fault. But the vac line may be split or disconnected inside.