Yet more fueling issues... 310B returns

[betyouaint]

In the history of all the cars I've owned, this one will go down as the car with the never-ending fuel system problems. Obviously, I've already been through the cam follower and HPFP failure which fortunately occurred 3000 miles before the extended 120k warranty ran out. I also replaced the electrical lift pump shortly afterwards and opted for the slightly cheaper Siemens VDO version. Still haunted with codes for fuel I changed both high and low pressure sensors, the FPR valve and N80 until I finally discovered that a contaminated camshaft sensor was to blame.

With only 40,000 miles on the new electrical pump, I'm getting the 310B code and occasional stuttering, usually under light load. I ran VCDS and the duty cycle on the pump is around 75-85% at idle. Older logs from my first pump failure show a similar figure with the post-replacement duty below 50% on the new pump at idle. I changed the LP pressure sensor as I had one lying around and then did the fuel filter, which was last changed with the previous pump replacement. To no avail, the pump is still running at high duty. I've just ordered a new pump but this time I opted for the genuine Audi part as suggested in this post from Jef at Ross-Tech...

http://forums.ross-tech.com/showthre...r-Audi-A4-2-0T

I've also read a number of other articles suggesting that non-Audi pumps can prove problematic or short lived. If my experience is anything to go by, I seem to be another case where this is true.

[Okedokey]

Have you checked the control module?

[RakkCity]

In the history of all the cars I've owned, this one will go down as the car with the never-ending fuel system problems. Obviously, I've already been through the cam follower and HPFP failure which fortunately occurred 3000 miles before the extended 120k warranty ran out. I also replaced the electrical lift pump shortly afterwards and opted for the slightly cheaper Siemens VDO version. Still haunted with codes for fuel I changed both high and low pressure sensors, the FPR valve and N80 until I finally discovered that a contaminated camshaft sensor was to blame.

With only 40,000 miles on the new electrical pump, I'm getting the 310B code and occasional stuttering, usually under light load. I ran VCDS and the duty cycle on the pump is around 75-85% at idle. Older logs from my first pump failure show a similar figure with the post-replacement duty below 50% on the new pump at idle. I changed the LP pressure sensor as I had one lying around and then did the fuel filter, which was last changed with the previous pump replacement. To no avail, the pump is still running at high duty. I've just ordered a new pump but this time I opted for the genuine Audi part as suggested in this post from Jef at Ross-Tech...

http://forums.ross-tech.com/showthre...r-Audi-A4-2-0T

I've also read a number of other articles suggesting that non-Audi pumps can prove problematic or short lived. If my experience is anything to go by, I seem to be another case where this is true.

Shit, I got mine from NAPA with an employee discount and it's at 55% at idle. I believe it was a VDO as well but may have been Delphi, I can't remember.

[betyouaint]

Have you checked the control module?

Nope. Might that produce these symptoms? How does one check the control module?

Also found the write-up from my previous replacement... I'll need this to remind me of all the mistakes not to make.

http://www.audizine.com/forum/showth...mp-Replacement

[betyouaint]

Shit, I got mine from NAPA with an employee discount and it's at 55% at idle. I believe it was a VDO as well but may have been Delphi, I can't remember.

Prior to replacement, the original was running in the 70-80% range at idle
After replacing with the VDO it was 45%-50% range at idle
It's now back in that higher range.
I don't think 55% is anything to worry about but it seems that the further it gets from 50% at idle, the more the pump is worn. Not sure when it becomes critical and what the natural aging curve might be?

[billyhoyle]

I just replaced mine and it was hitting around 84% load at idle (not good). The replacement hovers just under 50% at idle, but godDAMN if I don't still have a hidden 310B code. Ugh!!!

Is there a fuel pump adaptation that you can run in VAG-COM? After installing, my new one was running at almost the same load as the old one, but it slowly dropped (like it was adjusting itself to the newer more powerful pump).

[betyouaint]

I just threw my new pump in tonight. It would have been easier if I'd read my own guide first but still got it squared away in just over an hour. On initial startup the replacement pump was running in the 80% range and I had to rev the engine a little to purge the lines and get the duty cycle to finally drop down to low 50%

Next job was to check the seal but on driving the 5 miles to the gas station I was getting a real bad misfire. Fueling figures look fine on the logs but it does seem like a coincidence. I took the gamble to fill the tank to check the seal and hoped that the misfire had nothing to do with improper installation of the pump. Misfire is still present and I think I'll need to throw a coil at #3 to check it out.

One thing that was worrying/surprising was the state of the tank seal that I installed just a little over 2 years ago. It had disintegrated and was lying in the bottom of the tank (see photo). The only bit that was still in place was the part that was doing the sealing, trapped between the tank and the pump top. It's odd because it doesn't seem perished and looks more like it was ripped apart. I'll take a better look tomorrow but can't understand why this might happen to a new seal. The original was in reasonable condition when I changed the pump out the first time and that one had been in for 8 years. Maybe the seal was of similar quality as the Siemens VDO pump...?

[betyouaint]

I just replaced mine and it was hitting around 84% load at idle (not good). The replacement hovers just under 50% at idle, but godDAMN if I don't still have a hidden 310B code. Ugh!!!

Is there a fuel pump adaptation that you can run in VAG-COM? After installing, my new one was running at almost the same load as the old one, but it slowly dropped (like it was adjusting itself to the newer more powerful pump).

No adaptation that I know of...? Obviously I got the 310b code again when I started up the first time. I also got one on the way to the gas station along with the misfire codes. Once I'd filled up (from less than 1/8 tank), the 310b didn't come back on the home leg although the misfire did.

[billyhoyle]

I just threw my new pump in tonight. It would have been easier if I'd read my own guide first but still got it squared away in just over an hour. On initial startup the replacement pump was running in the 80% range and I had to rev the engine a little to purge the lines and get the duty cycle to finally drop down to low 50%

Next job was to check the seal but on driving the 5 miles to the gas station I was getting a real bad misfire. Fueling figures look fine on the logs but it does seem like a coincidence. I took the gamble to fill the tank to check the seal and hoped that the misfire had nothing to do with improper installation of the pump. Misfire is still present and I think I'll need to throw a coil at #3 to check it out.

One thing that was worrying/surprising was the state of the tank seal that I installed just a little over 2 years ago. It had disintegrated and was lying in the bottom of the tank (see photo). The only bit that was still in place was the part that was doing the sealing, trapped between the tank and the pump top. It's odd because it doesn't seem perished and looks more like it was ripped apart. I'll take a better look tomorrow but can't understand why this might happen to a new seal. The original was in reasonable condition when I changed the pump out the first time and that one had been in for 8 years. Maybe the seal was of similar quality as the Siemens VDO pump...?

This happened to me too, but not nearly as severely - I only had a few little chunks of rubber. In my case, I'm 100% sure I didn't tighten the ring on the top of the fuel pump and seal enough. A word of advice - empty your tank and clean that out of there! I eventually (2 years later) had to replace the fuel pump and filter, and a few little chunks had made their way through the screen on the bottom of the pump and were clogging things up. It wasn't catastrophic, but definitely caused the pump to work harder than it should have been, leading to an early death.

[billyhoyle]

No adaptation that I know of...? Obviously I got the 310b code again when I started up the first time. I also got one on the way to the gas station along with the misfire codes. Once I'd filled up (from less than 1/8 tank), the 310b didn't come back on the home leg although the misfire did.

Nice. Check your coils and plugs as a first step for diagnosing the misfire.

[b7_Andy]

I sold a fuel pump control module to a guy who had literally replaced every component of the fuel system and ignition system. He didn't tell me what codes he had but said that basically the car would misfire and run like ass all the time. I sold him the control module and after he installed it he said it fixed all of the problems... To bad it was one of the last parts he could have replaced! Anyway you should be able to find a used one for around $50.


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[betyouaint]

This happened to me too, but not nearly as severely - I only had a few little chunks of rubber. In my case, I'm 100% sure I didn't tighten the ring on the top of the fuel pump and seal enough. A word of advice - empty your tank and clean that out of there! I eventually (2 years later) had to replace the fuel pump and filter, and a few little chunks had made their way through the screen on the bottom of the pump and were clogging things up. It wasn't catastrophic, but definitely caused the pump to work harder than it should have been, leading to an early death.

Have to wonder if that's what caused the premature failure of the pump...? There didn't seem to be any pieces that had made their way into the basket but maybe they are in the pump.

There's no reason I can see why the seal should be in that state. The lock ring is definitely as tight as it needs to be and it would certainly leak if that was not the case. I doubt it was over-tightened as I marked the ring position before removal.

[betyouaint]

I sold a fuel pump control module to a guy who had literally replaced every component of the fuel system and ignition system. He didn't tell me what codes he had but said that basically the car would misfire and run like ass all the time. I sold him the control module and after he installed it he said it fixed all of the problems... To bad it was one of the last parts he could have replaced! Anyway you should be able to find a used one for around $50.


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Not sure I need a control module. The pump replacement fixed the duty cycle and fueling issue. I'll check plugs and coil before I start the inevitable wild-goose chase.

[betyouaint]

Coil #3 replaced courtesy of Advance Auto lifetime replacement warranty and all seems well. The noise from beneath the car without the pump cover and rear seat fitted is a bit disconcerting so it's good to have it all back together but it did remind me that I need to fit the new exhaust mid section that's been sat in the garage all summer.

[b7_Andy]

Good it was just a coil haha... My B5 has been running like ass the whole week, couldn't figure it out. I was super relieved when I simply cleaned oil of my spark plugs, put em back in and it was good to go!


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