Help diagnosing a P0087

So our 2009 UK spec started displaying some classic symptons you guys have seen before..

I purchased the car from a used car dealer and within days we had a 'would not start issue' even though the engine was warm, however, it starts fine next day. Our local main VW dealer diagnosed fuel contamination, said they could smell it, and then cleaned everything, flushed and put half a tank of diesel in it. I do not have the receipt for this as this was paid for by the used car dealer as a peace offering and to try and get to me accept the car. Thinking this is all good now, I agreed and took delivery back from the dealer, I also checked and there were no codes in the engine.

Just 3 days later my wife gets a limp home condition and flashing glow plug, she also described an audible buzzing sound from the engine bay, she drove home and parked. When I get to the car it starts and runs fine with no limp home displayed or other permanent message but VCDS shows
1 Fault Found:
000135 - Fuel Rail/System Pressure
P0087 - 000 - Too Low

I then drive 5 miles and I too get the limp home condition and as I have the laptop and VCDS with me I plug in, the pressures looked ok-ish, with the actual following the specified quite well. Logging the data I see the odd sample where the difference is -88 bar but on the whole the differences are seldom more than 20 bar. The buzzing sound is there and sounds like a fast whirring coming from the back left hand side of the engine as you look in.

I parked up for 5 days to read about what all this could mean - this forum has a LOT of technical info that has been great. I want to get the car to my local VW guy (an independant). The car starts perfect, all pressures looked good, the buzzing sound is gone too, so I then elect to drive 10 miles to the independant VW dealer - I logged the journey on VCDS to try and capture the limp home trigger point. Did not happen, nor did the buzzing sound, and my local guy is puzzled as the car behaves perfectly but has 2 limp home codes.

We're in diagnosis mode so they inspect the main filter to be perfect clean, the quantity regulator on the HPFP also spotless, the fuel tank lift pump is also super clean. So we have ruled out HPFP failure as there is no contamination/particles/debris etc. And besides it sounds like when they go - they go.

What could it be? The quantity regulator or the pressure regulator - to me the pressure regulator is on the right hand side on the end of the rail (correct?) and the quantity regulator is on the left front on the pump. Neither of these match the approximate location that time when we heard the noise.

What next? Gamble the pressure regulator at about $300 or the quantity regualtor (price unknown as yet)?

Anyone had one of these fail or a similar buzzing sound / failed component?

Appreciate some thoughts on this, and thank you for reading this far into a new guys first post - I normally hang out on the air cooled forums on other sites being a die hard VW guy. Regards.

Welcome busandcamper! Another aircooled enthusiast, great news.
Another member here has recently experienced very similar conditions to your description. He is currently diagnosing the problem on his own, with input from others here.
Have a read through this, and hope it may help:


http://forums.tdiclub.com/showthread.php?t=369958

You are right on at your descriptions and locations of the items you mention.
Sorry to hear about these issues, especially as you just got the car and haven't found out how wonderfull it really is!!
All the best,

Just for a quick check. Look under the backseat to make sure the supply (black) and return (blue) fuel lines are on the proper connections on the fuel sending unit. If somehow,someway these lines get reversed. The car will still run but experience the problem you are having. Who knows what the past history is on a used car. Its worth a check just to verify that the fuel lines are installed correctly. This same condition has happened before when a careless VW Tech has reversed the fuel lines on the sending unit. If the lines are reversed at the lift pump it will cause the aux fuel pump under the hood to buzz.

Good luck,
dweisel

Hello busandcamper,
The buzzing noise could very well be the electric aux pump mounted near the engine. It would be great if you could post your logs so others can review. dweisel is correct about fuel lines being reversed. Once bought a diesel Ford Escort for $100.00 because the it would not stay running after a head gasket replacement. Turned out they had the supply and return lines reversed on the fuel pump causing the fuel to be aerated. Aerated fuel on a CR engine will take out the HPFP in no time due to lack of lubrication. On another post, a VW mech stated during his CR training it was noted that the P0087 code would be logged anytime there was a 150 bar diff between requested and actual. You can manually activate the fuel psi reg on the rail by quickly applying and removeing 12v. The reg will make a slight clicking sound. You shouldn't be able to hear the click sitting in the cab without the engine running and definitely not with the engine running. I do not have a repair manual at this time so I'm not sure if the aux fuel pump is powered through a relay. Relays can make alot of clicking/buzzing noise if shorted, bad connection or sometimes when failing.

Quick thought. Since you have vagcom have you manually turned on the elec fuel pumps to check for the noise? ---Basic Settings. Go to block 35 and select run fuel pump, press ON and it will run both the in tank and axillary fuel pumps.

Hello IT313, glad you are back at it after a tough few weeks. Lift pump should be close to 12psi
Aux boost pump should be 62psi
Here is a link to some pressure numbers and testing from last spring.
http://forums.tdiclub.com/showpost.php?p=3747602&postcount=30

All the best,

Awesome write up!!!!!!!!!!!!

Your fuel filter system is first class. Now I understand the name 2micron.

I have been contemplating a small filter/screen for the return system in case of HPFP failure, but your setup blows anything I've thought up out of the water!

Thanks for leading the way.

You mean post the log of the error code or the file or screen shot of the log. Is there a way to attach files to this forum or do I use my own hosting? Anyway this is the P0087 - I found it odd the date got reported as waaay in the future;

Address 01: Engine (CBA) Labels: 03L-906-022-CBA.clb
Part No SW: 03L 906 022 LA HW: 03L 906 022 G
Component: R4 2,0L EDC G000SG 6172
Revision: 13H01--- Serial number:
Coding: 0001072
Shop #: WSC 01357 011 00200
VCID: 6FED6F877E641660C8F

1 Fault Found:
000135 - Fuel Rail/System Pressure
P0087 - 000 - Too Low
Freeze Frame:
Fault Status: 01100000
Fault Priority: 2
Fault Frequency: 2
Mileage: 93207 km
Time Indication: 0
Date: 2104.14.03
Time: 15:57:33

Freeze Frame:
RPM: 2093 /min
Inj. Quantity: 44.2 mg/str
(no units): 5.0
Pressure: 1272.0 bar
Pressure: 976.0 bar
Temperature: 45.0°C
Tank Cont.: 24.4 l

Readiness: 0 0 0 0 0

So we checked the fuel lines and they look correctly attached at both the tank end and the aux fuel pump end. We have not checked the lines are correct inside the tank lift pump assembly - cold these be wrong?

We're looking at putting a replacement aux fuel pump in, and are going on the following part number 5N0 906 129 B, runs to about £100 GBP new. We'll clean through the screen at the temp sensor too which is in the line connecting the aux pump to the HPFP.

Thank you for your help thus far.

As an update, we replaced the aux fuel pump at a cost of £240 + 1 hour and we didn't afford the time to measure the fuel pressures before the change and after. We've only done a few 10's of miles on the car since the changeout but so far so good - no codes or repeats so far.

Does the ECU have any spare inputs that are hooked up enough that we could use them for logging through VCDS? I realise diverting one of the main pressure sensors to this line would trigger all sorts of codes but if there was only a way to log while driving without going to the trouble of hooking up my innovate motorsports logger as I dont have an OBD11 cable or a 0-100psi range pressure sensor..

AL

Another update, all a little frustrating really.

Driving the car today I notice the buzzing sound again, but no limp home (yet) so we pull onto the drive and pop the hood. The buzz is quite loud and is coming from the vibration in the fuel line that connects the output of the aux pump to the HPFP and as you move the line the sound can be affected.

To me the vibration feels quite excessive and is harsh enough to transmit into the frame of the aux pump causing the noise. You can hold the fuel line but it will fatigue your fingers after a while - about 3-5mm of movement suggesting a lot of energy is going into creating this vibration.

Being a brand new pump with less than 50 miles on it I dont suspect it, but to rule it out I ran the block 35 pumps and there was no noise / vibration - just a nice genlte whir.

We were low on fuel so we drove to the nearest garage (about 4 miles) and put 3/4 tank of Shell v power just in case its level related. We logged some channels during a full throttle blast on the way home but to be honest the high pressure side all looks ok to me. Thoughts or suggestions?

This is the log file
http://www.busandcamper.com/images/temp/TDIclubexcelGolf6issue.xlsx

This is the autoscan results from the last 2 months.
http://www.busandcamper.com/images/temp/Log-LB09EBA-WVWZZZ1KZ9W470687.txt

And in case thats not allowed some screenshots;

busandcamper said:

Another update, all a little frustrating really.

Driving the car today I notice the buzzing sound again, but no limp home (yet) so we pull onto the drive and pop the hood. The buzz is quite loud and is coming from the vibration in the fuel line that connects the output of the aux pump to the HPFP and as you move the line the sound can be affected.

To me the vibration feels quite excessive and is harsh enough to transmit into the frame of the aux pump causing the noise. You can hold the fuel line but it will fatigue your fingers after a while - about 3-5mm of movement suggesting a lot of energy is going into creating this vibration.

Being a brand new pump with less than 50 miles on it I dont suspect it, but to rule it out I ran the block 35 pumps and there was no noise / vibration - just a nice genlte whir.

We were low on fuel so we drove to the nearest garage (about 4 miles) and put 3/4 tank of Shell v power just in case its level related. We logged some channels during a full throttle blast on the way home but to be honest the high pressure side all looks ok to me. Thoughts or suggestions?

This is the log file
http://www.busandcamper.com/images/temp/TDIclubexcelGolf6issue.xlsx

This is the autoscan results from the last 2 months.
http://www.busandcamper.com/images/temp/Log-LB09EBA-WVWZZZ1KZ9W470687.txt

And in case thats not allowed some screenshots;

Click to expand...

Hello bus/camper! We all understand your frustrations! So far, you and IT313 have diagnosed and helped us all understand this system better, cheers to bot of you!
The crazy experiments I have been up to with extra long lines, flow meters and gauges sometimes a produce very loud "pig squeal" sound and quite a vibration, similar to your description. For me, this is air in the lines. I literally have to beat the rubber lines with a wrench - (spanner for you!) to purge and bleed the air out, while the pumps are running. Then let it sit for a couple of minutes, then do it again.
Takes a couple of cycles, but it does clear.
Possible this may be your noise and vibration?
Hope this helps!
Cheers! Updated- the air in my lines does not come back again after a thorough bleed/purge.

So we have another clue.

This morning with renewed enthusiasm I re-checked the electronic valve on top of the pump but all was clean - no debris or contamination. Ok so back together and ran the 0035 pumps twice in their cycle and really worked that feed hose - tapping and bending etc. On startup of the engine there is no buzz/whine sound and the feed pipe to the HPFP is smooth and not bussing like crazy. Okaaay but I don't get the feeling I fixed anything.

A quick drive around the local town to get some heat into the car - took laptop with me logging the high pressure side again. Drove for about 20 minutes tops and on return nothing, no noise or buzz and the feed pipe smooth. Nothing noteworthy in the log file either.

I'm dreading the next long journey - we've made 2 long journeys since purchase and both times have led to a buzz - the 1st long journey led to the P0087 and the second journey was long enough to make a buzz but only in the last 5 minutes of the trip.

So how about a diagnosis that says when on a drive for longer than say 40 minutes the HPFP goes into some sort of state whereby it vibrates that feed line like crazy leading to the buzzing sound. After cool down all is well.

I'm contemplating a pre-emptive change of the HPFP - I'm assuming its not timed so would it be possible for a competent mechanic - is there a 'how to' somewhere on this or do i need an array of tools like belt locks and pins etc. I have pullers and an array of Hazet tools but nothing specialised - i normally work on air cooled cars.

Thoughts / suggestions? Thank chaps you for your help thus far in this issue,

And Happy New Year to y'all.

busandcamper said:

So we have another clue.

This morning with renewed enthusiasm I re-checked the electronic valve on top of the pump but all was clean - no debris or contamination. Ok so back together and ran the 0035 pumps twice in their cycle and really worked that feed hose - tapping and bending etc. On startup of the engine there is no buzz/whine sound and the feed pipe to the HPFP is smooth and not bussing like crazy. Okaaay but I don't get the feeling I fixed anything.

A quick drive around the local town to get some heat into the car - took laptop with me logging the high pressure side again. Drove for about 20 minutes tops and on return nothing, no noise or buzz and the feed pipe smooth. Nothing noteworthy in the log file either.

I'm dreading the next long journey - we've made 2 long journeys since purchase and both times have led to a buzz - the 1st long journey led to the P0087 and the second journey was long enough to make a buzz but only in the last 5 minutes of the trip.

So how about a diagnosis that says when on a drive for longer than say 40 minutes the HPFP goes into some sort of state whereby it vibrates that feed line like crazy leading to the buzzing sound. After cool down all is well.

I'm contemplating a pre-emptive change of the HPFP - I'm assuming its not timed so would it be possible for a competent mechanic - is there a 'how to' somewhere on this or do i need an array of tools like belt locks and pins etc. I have pullers and an array of Hazet tools but nothing specialised - i normally work on air cooled cars.

Thoughts / suggestions? Thank chaps you for your help thus far in this issue,

And Happy New Year to y'all.

Click to expand...

Happy New Year and your work this this morning is very encouraging! No visual contamination in the Metering valve on top of the HPFP is always good news.
After you removed the air in the hose by a longer then normal bleed and vigorously working the hose, the noise and vibration is gone. Good news!
Drive on and monitor the noise.
If it comes back, try one more vigorous bleed, even when the car is idling.
If it comes back again, air must be generating somehow between the feed pump and boost pump.
Try it again, go on your drive, enjoy it!
I have had the same noise and vibrations before, (but with much longer hoses, gauges and flow meters installed) but always perform a longer than normal bleed cycle and work the hose, to get the air out, same noise is gone.
Good work, don't get frustrated!
All the best!

Ok, good news and bad news.

The bad news is the problem is not fixed - I'm getting P0087 almost on demand now. It only takes a long journey to get it to trigger.

The good news, if you can call it that, I was able to capture these events on VCDS.

Armed with laptop I went on a long drive, waiting for the buzz, sure enough after about 40 minutes I could hear it. So pull over and boot up the VCDS and log HPFP values. More driving, maybe 10 minutes more, and I got a limp home condition, so i pulled over stopped logging, clear the code then drive 500 yards trigger again, choose a different group of logging, clear codes and drive 500 yards to trigger it. There has to be more clues in this data - this is where I need another pair of eyes on the data. Please help me analyse the log files.

What I have observed so far, my fuel temperature seems high, the first CEL was at 58 deg C and the last one at 85 deg C. Once in this temperature zone I get regular control pressure deviations, the 2 miles home I counted 4 in the data.

The next observation is this is now the same as lt313 with drops in actual fuel pressure in the 1-2 second region that triggers the CEL/MIL.

Reading his post, and then a few by specsalot I'm heading towards either a pump on the way out OR a compromised fuel overflow valve as suggested by dwiesel to lt313.

I loaded the excel files, and a screen shot - these should appear in this post next;

There are 4 log files each with a different set of logged channels. Error codes were cleared after each occurence as I did not turn off the engine.
In chronological order;

http://www.busandcamper.com/images/temp/Saturday%20first%20MIL%20LOG-01-071-13F-198-20F-218.xlsx

http://www.busandcamper.com/images/temp/Saturday second MIL LOG-01-21F.xlsx

http://www.busandcamper.com/images/temp/Saturday third MIL LOG-01-186-19F-208-218.xlsx

http://www.busandcamper.com/images/temp/Saturday drive home LOG-01-046-05E-071-193.xlsx


This excel graph shows the P0087 low fuel trigger event, the data at 7 Hz or so, quite detailed, just one of the analysis graphs in the excel files above;



Where I need the help is in locating this (curtesy dwiesel);



As my engine bay looks like this (curtesy specsalot), now I see where the purple line comes out of the HPFP but I dont see the valve that dwiesel is talking about? Help..

OK, so I did a little tear down investigation work this morning.
The roller looks ok



The top valve was clean


But the diesel in the pump looks cloudy - is this water contamination? The quantity valve also had this cloudiness - I thought maybe its extreme aeration following the hot fuel and multiple loss of pressures yesterday. What do you guys think?


And on closer inspection there is a slight scuff mark on the piston;


And maybe the corresponding mark on the inside of the body;



I could not safely get to the overflow valve that I wanted to, I challenge anyone to actually take that out with the pump in the car.

So I have some unanswered questions;

1. Is my fuel temperature a clue?
2. Does that look like the piston siezing and could this be my loss of pressure?
3. Is that fuel correct with the cloudy nature to it?
4. What do I do next?

Check your Thermostaic Valve

Hello Bus / Camper,
Good work, you have really dug into this.
1.)Is my fuel temperature a clue? -Fuel Temp looks quite high.
2.)Does that look like the piston siezing and could this be my loss of pressure?-Little scuffs on follower and bore look very familiar and not likely mild seizing. If the follower did seize, the damage would likely be more scoring. This looks very familiar to many pump bores and follower scuffs I have been experimenting with.
3.)Is that fuel correct with the cloudy nature to it?-Fuel looks like it has air in it. How long has this fuel been sitting since the last time you ran your car, or pumps?
4.)What do I do next? -Look into your Thermostatic Valve. I wonder if it has been cycling the fuel constantly back into the filter canister and creating the extra heat, and somehow adding air into it?
Check your PM for some more detailed thoughts about temporarily By-Passing the Thermostatic Valve.
Hope this helps!
All the best,

Hi, ok not so good news.

With the help of this forum I now know I'm chasing high fuel temps (80 deg C) and a severe case of aerated diesel - so something is wrong and a case of what is it?

A tip from 2micron suggested a thermostat bypass, so I rigged a bypass of the thermostat in the fuel filter housing - as in the picture. Everything looks as if it should work, but when i run the pumps in group 35 I get an odd response - sort of a zzzzttt and then no further sound from the aux pump as if it stopped pumping. The pump does make an odd tick / click but defintiely no whirring like we've heard before. Also you'll see we plumbed a clear line for the loop on the filer can but there was never any diesel in this line.

All a little odd, but not to be deterred I rigged up some clear line on the HPFP to tank joint and verified diesel was indeed flowing. On the spur of this I tried to start the engine but it stumbled and coughed, missed and then coughed some more, cut it off before something baad happened. On inspection in the engine bay I'm met with a soaked engine - diesel sprayed everywhere. Difficult to trace but we have a leak from the top of the engine as a clue maybe (pic).

Break out the rags, engine gunk and clean up. I return the piping to normal, bleed the system with 4 cylces of group 35 and the engine fires and runs perfect - a 20 minute drive backs this up.

So what next? My guess is the return line to the tank is blocked, and on my engine the diesel is being cycled from HPFP to the filter can back to the aux pump indefinitely and this is why I get aerated and high fuel temps. Even if the thermostat is open to say 'go back to the tank now' with the blockage there is no chance of this. Only when the fuel gets used by the engine does fresh fuel enter the system. To sort of back this up a little in my last 'drive home log' I observed a steady drop in fuel temp, starting the log at 86 deg C and ending at 80 deg C after a 5 minute drive.
http://www.busandcamper.com/images/temp/Saturday%20drive%20home%20LOG-01-046-05E-071-193.xlsx

Am I on the right track? Plan is to purchase a pressure gauge, bypass again and investigate why I cant cycle diesel back to the tank like normal. Kinked pipe? Wrong connection? Or debris in the line maybe?

Does the fiel line run through the underbody covers or can I visually inspect it all the way? My drawback is I have a fair selection of tools but not a 2 post lift to get the car in the air.

Any thoughts suggestions? Appreciate the help thus far chaps - thank you,

rgds, AL


.

.
Leaked from here with a drip drip

Quite a messy day you have had! You did the bypass the same way mine has been running for months now. It looks like you just found the problem! You are on the right track and proved the return line is blocked, preventing the fuel returning to the tank and over pressurizing the return lines on top if the motor.
The over Aux pump is a positive displacement pump and the click, tick, click, is the pump stopped, trying turn, like you described. The leaks are simply the return lines on top of the engine not being able to cope with the full pressure of the aux pump. With the lines in the factory positions, the return fuel is most likely being bled back along the lower pressure feed line, fighting all the way and creating air somewhere in the feed pump, possibly causing it to cavitate?
I can only suggest to trace the return line and check for any issues and or the connection at the tank, like you said!!
You are in the right track and I can see you resolving this very soon.
Check your PM.
Hope this helps!! By now, you must be getting frustrated!!
All the best,

Just catching up on your progress. Looks like your on the right track. You may have already done this but an easy way to prove your plugged return line theory would be to run a temporary line from the metal return line on the engine back to the fill tube on the tank. Just make sure it's secure enough for your road test and hopefully the tank is not full enough for fuel to splash out of the fill neck while driving. If this fixes the problem then you can start isolating the individual lines from there. Just remember to start on one end and work to the other. Since you are the second owner it's possible someone may have removed the rubber fuels line for some reason and when reattaching to the metal fittings may have created a flap, plugging the line. The metal fitting can shave the rubber on the inside of the hose as it is being pressed on causing a flap or blockage. It can happen on new hose but as they age it may happen more easily.

Just a quick note. I was able to duplicate your aux pump buzzing today by pinching off the fuel return line where it leaves the filter and goes to the tank.

Nice troubleshooting. I was thinking about doing the same...obviously I was too lazy.

lt313 said:

Just a quick note. I was able to duplicate your aux pump buzzing today by pinching off the fuel return line where it leaves the filter and goes to the tank.

Click to expand...

If you have not already checked. Double check to make sure the supply/return lines are not switched at the in tank fuel sending unit. I briefly read the thread,so I'm not sure if you already did this. Your symptoms sure sound like this is what is going on.

Good luck,
dweisel

Well this could be it.

So despite re-assurance from the local VW specialist that all in the tank was ok, I took dwiesels advice and had a look.

This is what I found - Oh dear swapped lines, dayum


So switch them back, and 5 minutes later I'm rolling down the road - I drove for 40 minutes and got bored burning diesel (its expensive here) to see temps quikly climb to 15 and then hover around 22 for the remainder of the drive - looks like thermostat behaviour to me. No long journey but am scheduled fro one on Sunday - will report back if it goes t1ts after that.

So I'd say this was it. Dayum that was easy - if only I checked that myself.

My thanks to dwiesel, 2micron, lt313 and others on this forum for their help, I will endeavour to return the favour when I can see where I can contribute.

Rgds, AL

I love when a problem gets sorted out with help from the forum.

That residual fuel in the pump bore looks a little "off". Maybe it's just the photography. I'd get a tank full of fresh fuel in that car pronto.

busandcamper said:

Well this could be it.

So despite re-assurance from the local VW specialist that all in the tank was ok, I took dwiesels advice and had a look.

This is what I found - Oh dear swapped lines, dayum

So switch them back, and 5 minutes later I'm rolling down the road

Click to expand...

.
This picture has the lines reversed. The blue line should be closest to the electrical plug.

Swapping fuel lines

Did this really fix your problem. My 2010 JSW fuel lines are connected same as what your picture shows. I swapped them (put blue closest to elec connector) but car still throws low fuel pressure code P0087.

So after a year now, were you able to solve the problem for the low fuel pressure code P0087 .

Thanks for that thread , i think am having the same problem, but mine seems to be coming from the check valve stuck on the fuel filter housing which allows the fuel from injector return line to be back to hpfp at first start in the morning but after warming up ,fuel temperature becomes to high and check valve allows air to get to hpfp making it noisy , that’s what am thinking didn’t nothing until now but am thinking in changing the fuel filter housing , can anybody give me his opinion?