PlasticMac
Admin Team
A compression test would give you a clue as to the health of the mechanicals.
Mac.
Mac.
Crgwal
A2OC Donor
Did a compression test a few months back, looked normal on 3 of 4 cylinders with one being a little lower but within limits.
Just finished replacing my rear brake calipers after poor handbrake performance and grinding brakes that didn't release fully. Night and day now, and a nice tight and strong handbrake.
The good news is on top of this. I managed to resolve the bogging down engine on restarts when hot and I also completely removed the sputtering and misfiring sounds when I idled the engine hot!
I did two things but I can only guess one of them fixed it.
Replaced the fuel pump and replace the lambda sensor. The fuel pump was replaced with a different second-hand one last year but I decided to do it again.
I really couldn't guess which did the fix for sure, but the way the engine behaved was as if the ECU was compensating for something, and perhaps it's more likely it was the Lambda sensor?
Next up, a new stainless steel exhaust for that car which is booked in already
Happy days.
Note: for anyone just reading this part I had no engine faults showing up on VCDS before or after the works.
Just finished replacing my rear brake calipers after poor handbrake performance and grinding brakes that didn't release fully. Night and day now, and a nice tight and strong handbrake.
The good news is on top of this. I managed to resolve the bogging down engine on restarts when hot and I also completely removed the sputtering and misfiring sounds when I idled the engine hot!
I did two things but I can only guess one of them fixed it.
Replaced the fuel pump and replace the lambda sensor. The fuel pump was replaced with a different second-hand one last year but I decided to do it again.
I really couldn't guess which did the fix for sure, but the way the engine behaved was as if the ECU was compensating for something, and perhaps it's more likely it was the Lambda sensor?
Next up, a new stainless steel exhaust for that car which is booked in already
Happy days.
Note: for anyone just reading this part I had no engine faults showing up on VCDS before or after the works.
PlasticMac
Admin Team
Is that the electric pump?Did a compression test a few months back, looked normal on 3 of 4 cylinders with one being a little lower but within limits.
Just finished replacing my rear brake calipers after poor handbrake performance and grinding brakes that didn't release fully. Night and day now, and a nice tight and strong handbrake.
The good news is on top of this. I managed to resolve the bogging down engine on restarts when hot and I also completely removed the sputtering and misfiring sounds when I idled the engine hot!
I did two things but I can only guess one of them fixed it.
Replaced the fuel pump and replace the lambda sensor. The fuel pump was replaced with a different second-hand one last year but I decided to do it again.
I really couldn't guess which did the fix for sure, but the way the engine behaved was as if the ECU was compensating for something, and perhaps it's more likely it was the Lambda sensor?
Next up, a new stainless steel exhaust for that car which is booked in already
Happy days.
Note: for anyone just reading this part I had no engine faults showing up on VCDS before or after the works.
Mac.
Crgwal
A2OC Donor
Yeah the one under the seats
PlasticMac
Admin Team
That's the second one recently. Previously it was preventing warm starts, as pressure is increased to overcome vaporising. Again, I guess it has run on and off for close to 20 years, so not surprising. Have you got a part number, and approximate cost please.
You can check the fuel pressure with VCDS
Mac.
You can check the fuel pressure with VCDS
Mac.
Crgwal
A2OC Donor
8Z0919051C - £37.50 from ebay. If that's what you are asking?
Yeah, I have heard you mention this vaporising that needs overcome when the fuel is heated by a hot engine.
I assumed fuel pumps were far more reliable for this to actually be the issue.
Interesting you have seen this being a problem repeated in the FSI.
This is a lesson for me, to keep myself on the logical path when running into problems.
Been a fun ride, especially when this is my first car and the only car I have ever owned.
Yeah, I have heard you mention this vaporising that needs overcome when the fuel is heated by a hot engine.
I assumed fuel pumps were far more reliable for this to actually be the issue.
Interesting you have seen this being a problem repeated in the FSI.
This is a lesson for me, to keep myself on the logical path when running into problems.
Been a fun ride, especially when this is my first car and the only car I have ever owned.
PlasticMac
Admin Team
The high pressure pump is engine driven, so until the engine turns over, it does nothing. The electric pump primes it, so it's ready. We need to be carefull, before blaming the high pressure pump, that the electric one is operating at full pressure. If the pressure from the electric pump is low, so will the output of the high pressure pump.
Mac.
Crgwal
A2OC Donor
So my car was great for about three days and now I am back to where I started.
The second hand pump I got perhaps failed it would seem that way but this is already my third fuel pump in this car now.
Car bogs down when hot, low torque at high speeds.
I thought I had sourced a new fuel pump but after a call today from deutscheparts there was a mixup in the part numbers. Audi Tradition also don't have any as do Audi themselves.
I will run some more tests on VCDS lite and report back here soon.
The second hand pump I got perhaps failed it would seem that way but this is already my third fuel pump in this car now.
Car bogs down when hot, low torque at high speeds.
I thought I had sourced a new fuel pump but after a call today from deutscheparts there was a mixup in the part numbers. Audi Tradition also don't have any as do Audi themselves.
I will run some more tests on VCDS lite and report back here soon.
PlasticMac
Admin Team
@VVVVVV just supplied part number for lift pump, available on Amazon, and other online markets.
PIERBURG 702550540 or
PIERBURG 702550610
No idea what the difference between the two is though.
Mac.
PlasticMac
Admin Team
I've emailed the Pierburg distributor in UK, and asked what the difference between the PIERBURG 702550540 and the PIERBURG 702550610.
He's just asked for a VIN, so I've sent him mine. I'll post up when I get his reply.
We'll get there ... (not sure where though).
Mac.
EDIT: Pierburg 7.02550.61.0 is the correct part.
Mac.
Last edited:
PlasticMac
Admin Team
Elring Parts confirm the correct pump for the BAD Engine is Pierburg 7.02550.61.0
Mac.
PlasticMac
Admin Team
I think it would be fair to say that low fuel pressure, on both the low pressure side, (electric lift pump), and the high pressure side, (engine driven high pressure pump), is an area that should be better understood in diagnostic checks.
If hot starts are difficult, and poor performance when fuel demand is high are encountered, fuel starvation is, perhaps, as likely as the "traditional" electrics, coil packs etc. The electric pump is an obvious wear point on an 20 year old car. The wide availability from the motor factors on the bay, and elsewhere, would indicate brisk demand, so a common failure across the VAG range seems likely.
Mac.
If hot starts are difficult, and poor performance when fuel demand is high are encountered, fuel starvation is, perhaps, as likely as the "traditional" electrics, coil packs etc. The electric pump is an obvious wear point on an 20 year old car. The wide availability from the motor factors on the bay, and elsewhere, would indicate brisk demand, so a common failure across the VAG range seems likely.
Mac.
Last edited:
zago
Member
As far as I understood both pumps are the same. Just ..540 pump code is different as it sold together with white tank.
PlasticMac
Admin Team
The tank thing is the "swill pot"
Holds enough fuel to keep the engine supplied when you corner with a nearly empty tank.
Mac.