Ok, So leaving the driveway today in my 09' JSW "73,000 miles", the glow plug light came on and power dropped. Shut off the engine and restarted. Glow plug light & CEL went off but came back on during acceleration and power dropped again. Back at home, pulled codes with Vag Com. P0087 & P0191. Pulled fuel filter first thing. No metal or debris in filter. Approx 1500 miles on filter. Installed new fuel filter, cleared codes and drove. Same thing happened. Checked wiring for splits/cuts and loose connectors. All ok. Cycled both electric fuel pumps with Vag Com. Both working. Dove deep at this point. Pulled FQR out of HPFP. No metal or debris. Checked screen on HPFP inlet. No metal or debris. Pulled fuel pump out of tank. No debris noted around prefilter. Removed high pressure fuel sensor from rail and flushed with brake clean. No metal or debris came out. Removed high pressure rail from engine and checked the regulator for metal or debris. All ok. Called 3 dealers today after preliminary checking. 2 stated probably the fuel psi sensor and 1 wouldn't help. Purchased new fuel psi sensor from dealer. Still has same problem. I'm considering replacing the regulator and hesitant to take to dealer. Any ideas? Sorry this is long but wanted to give as much info up front as possible. There is a ton of info about low fuel psi codes and metal in filter from HPFP but mine isn't shedding metal "Yet". Thanks
Dreaded P0087 code - No metal in filter
- Thread starter lt313
- Start date
dweisel
Top Post Dawg
Could possibly be either be fuel pressure sensor(G47) or fuel pressure regulator(N276) at either end of the rail. Contact member 2micron,he knows these CR fuel systems better than anyone. Maybe he can help you out.
Check resistance on rail pressure solenoid
Hello it313,Sorry to hear these troubles.
Check the resistance of the rail pressure solenoid. All of mine (5) have 3.6 ohms. As well, the Fuel Metering Control Valve should be 2.8 ohms.
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I will give you one of my pressure solenoids, shipping would be a few days from Canada. Any one know the fastest expedited shipping??
All the best,
Hello it313,Sorry to hear these troubles.
Check the resistance of the rail pressure solenoid. All of mine (5) have 3.6 ohms. As well, the Fuel Metering Control Valve should be 2.8 ohms.
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I will give you one of my pressure solenoids, shipping would be a few days from Canada. Any one know the fastest expedited shipping??
All the best,
. Thanks for the comments dweisel, I really only learned about this system by experimenting. It has been a joy to learn, but I really only know enough to keep my wife and kids happy!!!
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Dweisel has the right thoughts and terminology here, after we check the resistance of these solenoids, and eliminate them, we can look in the high pressure side of the pump, which is very easy.
I'll draft up a play by play to open the top of the pump on the car.
All the best,
Finally had time to check resistance. With cold engine sitting over night 46*F the Rail PSI solenoid was 3.9 ohms. Fuel Metering Valve 2.8 ohms. Test drove. No CEL for 1st 2 miles then came on under hard acceleration. Retested resistance with engine @ operating temp. Rail solenoid 4.4 ohms. It was warm to the touch but not hot. Fuel metering valve 3.1 ohms. Felt about ambient temp which was 70*F per dash gauge.
dweisel
Top Post Dawg
To 2micron, seems like it could be electrical,but if resistance readings are okay. Could it possibly be something with the high pressure part of the hpfp? This would possibly be a reason for low pressure code and no metal particles in the fuel filter or fuel quantity regualtor.
Hopefully it's an electrical problem.
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So I removed the piston from from the HPFP. No sign of pitting or problems. Checked resistance again on the rail PSI solenoid & FMV along with temp readings. Rail PSI valve 4.3 ohms @ 34*c and FMV 3.4 ohms @ 27*c. Cycled Rail PSI solenoid with 12v 4-5 times. All OK. Took photos. Will post when I figure out how. Road tested to log problem with Vag Com. Tried hard acceleration and easy take off's from dead stop for 10-15 minutes. Could not duplicate original problem. Tried every bumpy road I could find "which isn't very hard" in case of loose connection/wiring issue. Drove for 30 minutes before CEL came on. Now CEL only comes on after extended highway cruise when you slightly roll into the throttle. You can clear the codes and drive for another 10-15 min before it comes on again. Group 21 log showed 296.0 bar high psi "specified" and 8.0 bar "actual", 15.0% Quantity measuring control valve when problem occurred. I have traced the wires back to the ECM and have not found any rubs or breaks. Checked the female pins in the connectors for spreading but all are tight. Have not removed main plug from ECM to check pin tightness. One thing I may have not mentioned is yesterday I replaced the fuel just to be safe. It looked fine, but went to a different station just to make sure. I also added a fuel conditioner Diesel Guard Clear made by Chemsearch. I normally do not add any conditioner. What are your thoughts on possible sticking rail psi valve due to wear and the additive is loosening it up or could there be a programing issue? Thanks for all your help so far.
Wow, quite an afternoon you have had!!!
I compared my "hot" vs "cold" resistance readings and gathered similar increases you have:
Rail Solenoid: 4.1 hot, 3.6 cold. (ohms)
FMV - 3.1 hot, 2.8 cold. (ohms)
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Not really sure if adding new fuel and additive has helped?? But Cycling the solenoid direct, seems to have prolonged the CEL intervals and reduced them?? It would be nice to swap the Rail Solenoid, only because changes for the better occurred after you cycled it. Not sure how expensive a new one is, but I would gladly send one of mine just to compare.
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Your VagCom data seems puzzling?
The "specified" and "actual" should be much closer. At idle, look for specified 300 bar, with the actual not far behind. You should be able to compare the VagCom data I sent you to see if the numbers are close.
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You are very handy, so this next test will be a snap.
Have a look inside the top of your HPFP "head". Inside is the Check Valve. You can do this with the head on the pump, in the car, simply by removing the 6 point, threaded cap:
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A 7/16" six point socket fits perfectly. Watch for the small, steel sealing washer, under the check valve. These components must all be Cleaner than Clean, and great care taken not to introduce any additional foreign material.
The little check valve must move freely and seat with a slight "snap". the High Pressure Plunger will not be removable with the Head on the Pump, in the Car.
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This is really interesting and the only good news is that you are a pioneer of the first (private) diagnosis of this problem. We will all benefit from your results, even if all of us as a team fail at the first attempts.
Keep up the good work, I'm not sure how you keep so calm, but as a group, we will certainly solve this problem!!
All the best,
I compared my "hot" vs "cold" resistance readings and gathered similar increases you have:
Rail Solenoid: 4.1 hot, 3.6 cold. (ohms)
FMV - 3.1 hot, 2.8 cold. (ohms)
.
Not really sure if adding new fuel and additive has helped?? But Cycling the solenoid direct, seems to have prolonged the CEL intervals and reduced them?? It would be nice to swap the Rail Solenoid, only because changes for the better occurred after you cycled it. Not sure how expensive a new one is, but I would gladly send one of mine just to compare.
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Your VagCom data seems puzzling?
.
The "specified" and "actual" should be much closer. At idle, look for specified 300 bar, with the actual not far behind. You should be able to compare the VagCom data I sent you to see if the numbers are close.
.
You are very handy, so this next test will be a snap.
Have a look inside the top of your HPFP "head". Inside is the Check Valve. You can do this with the head on the pump, in the car, simply by removing the 6 point, threaded cap:
.
.
A 7/16" six point socket fits perfectly. Watch for the small, steel sealing washer, under the check valve. These components must all be Cleaner than Clean, and great care taken not to introduce any additional foreign material.
The little check valve must move freely and seat with a slight "snap". the High Pressure Plunger will not be removable with the Head on the Pump, in the Car.
.
This is really interesting and the only good news is that you are a pioneer of the first (private) diagnosis of this problem. We will all benefit from your results, even if all of us as a team fail at the first attempts.
Keep up the good work, I'm not sure how you keep so calm, but as a group, we will certainly solve this problem!!
All the best,
Thanks for the expert and detailed instruction 2micron. I'll update after I open up the pump head. I may take you up on your rail psi regulator offer if everything starts to point that direction. Thanks again.
Great pictures It313!! Thanks for posting them and for being patient and carefull enough to open the pump. You are using the all the right steps and attitude to this issue.
For other folks watching, It313's work and reports will help us all.
Huge compliments to you!
PM me your address, I will expedite a spare rail solenoid Monday morning, to help compare and eliminate the possibility of it acting up.
All the best,
For other folks watching, It313's work and reports will help us all.
Huge compliments to you!
PM me your address, I will expedite a spare rail solenoid Monday morning, to help compare and eliminate the possibility of it acting up.
All the best,
Good morning all. Actually slept last night and awoke fresh. Decided to double check my work to see if anything was missed. Everything tested the same. I installed a clear fuel line on the HPFP inlet to make sure no air in the fuel. "Possibly sucking air somewhere and aerating the fuel". All OK. Remove check valve from top of HPFP per 2microns excellent instruction. All OK. Reviewed Vag com logs and included below. It appears that when the "specified" fuel and "actual" fuel psi are within 100 or so BAR the Fuel Quantity Control Valve "FQCV" stays in the 30-50%. When the "actual" fuel PSI drops over 100 bar from the specified the FQCV % drops into the 20's. Opposite happens when actual is higher than specified. FQCV % goes up. Unless someone has any other ideas I'm leaning towards a faulty "mechanically" Rail psi regulator.
What a detective!!
Good work!!! Your carefull tests and inspections have shown the pump is in good repair. If you have time, please log the group in VCDS that measures the Rail Pressure Soleniod duty. (I think it is group#20) We are all curious to see the same comparisons, related to pressure and solenoid duty.
This is a monumental effort on your part. Mechanical failure of the Solenoid is certainly possible and is adding up to be the answer here.
Many thanks.
Good work!!! Your carefull tests and inspections have shown the pump is in good repair. If you have time, please log the group in VCDS that measures the Rail Pressure Soleniod duty. (I think it is group#20) We are all curious to see the same comparisons, related to pressure and solenoid duty.
This is a monumental effort on your part. Mechanical failure of the Solenoid is certainly possible and is adding up to be the answer here.
Many thanks.
Sorry for the absence. Had a death in the family and now fighting a nasty cold. It's been a very trying couple of weeks. Anyway, The good news is that I received the loaner rail PSI regulator from 2micron. Many thanks my friend! The bad news is that it did not fix the problem. Since my last post here's what I have learned. Drive it like you stole it--No check engine light. Drive like you own it--CEL every time you touch the throttle. Basically if the rpm's are kept above 3000 it runs fine with heavy or light throttle. I've been unable to see anything with the VagCom logs so far to indicate anything other than the fuel PSI regulator. No codes for the Fuel Metering Control Valve. Any thoughts on the Fuel Metering Control Valve affecting the fuel psi and triggering the low rail psi code?
busandcamper
Member
I have something a little similar to your issue, and 2micron has noticed we're possibly tracking a similar intermittent CEL limp home issue. This is my thread, its not as interesting as yours tho;
http://forums.tdiclub.com/showthread.php?t=371346
What I have noticed from my log files and issue is;
The difference between specified and actual in the fault code logs are 1272/976 or an error of 296 bar. The values appear to only capture the first event - either that or the rpm was exactly the same when I got my 2nd CEL event which would be a minor miracle.
I'm working on the value and occurrence of this error - and so if the system triggers from this error then I'm looking for the moment that the pressure is 'dumped' from the rail or is duped by a spike in the readings somewhere. Looking at my logged data for this pressure error I have a standard deviation of 16 bar and a max of 40 and a min of -88. So my system appears to be tracking well. I have tuned PID style control systems and my data appears to be a typical PID system - there is lag but otherwise actual follows specified.
My quantity regulator is approx 35% at idle, and based on a 360 second normal drive with a couple of blasts I see a min of 25.3%, and a std dev of only 3.1, suggesting very few spikes or sudden changes in the way the system wants the valve to work.
Looking at your data;
You have a peak error of 416 bar - little wonder this triggers the CEL, but you have a sustained pressure error of more than 200 bar which lasts about 1 second, which is a long time - too long for a sensor spike - I'd hazard your system is genuinely low on fuel volume and this is backed up with the increase demanded by the quantity valve. So where is all that fuel going?
This is speculation;
I cant help thinking your system is losing volume somehow and the system tries to cope by operating the valve to deliver more volume. Higher rpms generate a lot more volume so high rpm driving may not create this issue. Do you have an injector fault that is putting more fuel in than is required and thereby using too much volume? I see you're going from off pedal to full pedal/throttle around this time. Is your injection quantity asking for extra fuel and this puts a demand on the system that for some reason your pump cant cope with?
http://forums.tdiclub.com/showthread.php?t=371346
What I have noticed from my log files and issue is;
The difference between specified and actual in the fault code logs are 1272/976 or an error of 296 bar. The values appear to only capture the first event - either that or the rpm was exactly the same when I got my 2nd CEL event which would be a minor miracle.
I'm working on the value and occurrence of this error - and so if the system triggers from this error then I'm looking for the moment that the pressure is 'dumped' from the rail or is duped by a spike in the readings somewhere. Looking at my logged data for this pressure error I have a standard deviation of 16 bar and a max of 40 and a min of -88. So my system appears to be tracking well. I have tuned PID style control systems and my data appears to be a typical PID system - there is lag but otherwise actual follows specified.
My quantity regulator is approx 35% at idle, and based on a 360 second normal drive with a couple of blasts I see a min of 25.3%, and a std dev of only 3.1, suggesting very few spikes or sudden changes in the way the system wants the valve to work.
Looking at your data;
You have a peak error of 416 bar - little wonder this triggers the CEL, but you have a sustained pressure error of more than 200 bar which lasts about 1 second, which is a long time - too long for a sensor spike - I'd hazard your system is genuinely low on fuel volume and this is backed up with the increase demanded by the quantity valve. So where is all that fuel going?
This is speculation;
I cant help thinking your system is losing volume somehow and the system tries to cope by operating the valve to deliver more volume. Higher rpms generate a lot more volume so high rpm driving may not create this issue. Do you have an injector fault that is putting more fuel in than is required and thereby using too much volume? I see you're going from off pedal to full pedal/throttle around this time. Is your injection quantity asking for extra fuel and this puts a demand on the system that for some reason your pump cant cope with?
Hello busandcamper. On my cars issue, I think you are right. I've considered plumbing in a psi gauge to check actual psi from the tank lift pump and again after the aux pump. One of the two could be weak and unable to supply the volume of fuel needed to the HPFP during high fuel demand. I have not logged any injector error codes so far. On yours, 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 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.
Update---- Finally had time to check fuel psi. Lift pump psi taken were it enters the filter 8.5 with the engine off and 9 psi with the engine running. Aux pump readings taken before and after inlet screen on the HPFP. 60 before and 59.5 after. Digital psi gauge used so was able to see the .5 psi difference. Checked the fuel lines from tank to filter to make sure none were kinked or crushed restricting fuel flow. Return psi 9 psi. My psi readings are slightly lower than those posted by 2micron. Could be a difference in the gauges.
2micron- Do you have any factory specs or know if there is a listing for min or max fuel psi regarding the lift pump?
2micron- Do you have any factory specs or know if there is a listing for min or max fuel psi regarding the lift pump?
Sorry It313, I have no "factory" minimum pressure values. The values I observed were 12 psi lift and 62 psi boost, taken from my car. I fully agree, the difference in our readings is simply a difference in gauges.
Is there any way you can monitor your new gauge(s) while driving and replicating your low pressure fault?? A longer set of hoses to get your gauge up to the windshield?? Just be damn careful while driving and monitoring!!
You are really forging a trail, troubleshooting this problem!!
All the best!!
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dweisel
Top Post Dawg
The aux pump should be making 73 psi. The fuel overflow valve on the hpfp should open at 62 psi to let fuel into the return fuel line.
dweisel
Top Post Dawg
The fuel overflow valve is located in the hpfp at the return fuel fitting. When internal fuel pressure reaches 62 psi this spring loaded valve opens. Its function is to maintain approx. 62 psi within the low pressure side of the hpfp. If you look at the hpfp you will see a two sided black nut. This is the fuel overflow valve or return fuel relief valve.
Below pic: showing two fuel overflow valves.
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Update-- It's been a while but wanted to update. Have not driven the car much since middle of December. Less than 600 miles but always had VagCom hooked up, resetting the check engine light as needed. I've been waiting for what ever is causing the problem to finally fail. Nothing has failed at this point. Decided to hook manual gauges back up, take a drive and check fuel PSI last weekend. Checked lift pump psi first. Psi taken at fuel filter inlet. Found that on cold start up I had 9.2 lbs @ idle. After 5 miles of driving it dropped to 7.2 and finally settled around 3.4 lbs. Came back up to 7 at idle after drive. Replaced the in tank pump and PSI is steady @ 19 psi when driving or idle. NO check engine light. I have put 200 miles on after pump replacement and all is well so far. Fuel psi from aux pump @ HPFP inlet is steady @ 70. It appears that when the lift pump is worn to the point it will only build 8-9 psi it is also not delivering the volume needed. It would be nice to know VW min psi or min GPH/LPH flow for the lift pump. Based on my findings it appears lift pump psi below 12 psi may cause you a problem.
Want thank everyone for all the help!
Still holding my breath, but will feel better after 1000 miles and no problems.
Hope this helps someone else out there.
Start up @ idle
After 5 miles
Under load after 10 miles
New pump @ idle
Want thank everyone for all the help!
Still holding my breath, but will feel better after 1000 miles and no problems.
Hope this helps someone else out there.
Start up @ idle
After 5 miles
Under load after 10 miles
New pump @ idle
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tdiatlast
Top Post Dawg
- Joined
- Jan 21, 2009
- Location
- Fort Worth, Texas
- TDI
- 2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
You, sir, and 2micron, should both be nominated for sainthood. You both have amazing patience, and curiosity.
Thanks for allowing us to watch how this repair has evolved. Absolutely amazing.
Thanks for allowing us to watch how this repair has evolved. Absolutely amazing.
Sella Turcica
Veteran Member
Amazing thread. I love these.