[loujet]

2009 Touareg V6 3.0 TDI

Quickly, last week wife is driving around in town, -20c, engine hesitate a few times, then message in dash say go to shop right away then dies... She gets the Touareg towed... back home!! I get in the garage (nice work out..) to get melt it a little, change the battery for a new one while at it. Then re-tried, engine turning but no start. Fuel coming back to the filter after the hpfp at a steady rate, did 3 time the high pressure priming with the n276 (?) pressure control of the rail unplugged. Reset code then, still nothing. I am now clueless after 4 days...

This is what I see when trying to start
189 /min Engine Speed (G28)
26.0 mg/str Injection Quantity
26.0 mg/str Start Injection Quantity
411.3 mg/str Mass Air Flow (actual)
10.03 V Supply Voltage (Terminal 30)
0.00 mg/str Injection Quantity Deviation Cyl. 1
0.93 l/h Fuel Consumption
283.8 bar High Fuel Pressure (specified)
309.6 bar High Fuel Pressure (actual)

 

[gazaflash]

Do you have a VAGCOM? What error codes come up. Possibly stuck fuel pressure regulator? 10 Volts seem a bit low. See any aluminium debris in the fuel filter??

 

[loujet]

Yes I do have vcds, no codes showed when it died...

Voltage seems a little low but these reading were taken during cranking. High pressure reading seems ok, this would indicate hpfp would be ok, right? While cranking at one point I did collect about 500 ml of returning diesel from the hpfp, it flowed plenty I guess, hard to say but the flow was about the same "size" a the diameter of the hose...

 

[gazaflash]

That’s weird...! I would have thought, since the ECU shut the engine down, there would all sorts of error codes!
When you say “500ml”, is that 500ml flow in 60 sec? Do you have an oscilloscope? Worth fitting to one of the injectors to see what type of voltage trace there is. If the injectors aren’t firing, then you will get more fuel returning to the tank. Check fuel pressure relief, fuel regulator
This is baffling, to say the least. I guess its time to start taking things apart.

 

[loujet]

gazaflash thanks for your input!

More details the only new codes showing after were these:

001674 - ECM Power Relay Load Circuit
P068A - 000 - Opens Too Early - Intermittent

000897 - Glow Plug/Heater Indicator Circuit
P0381 - 000 - Implausible Signal - Intermittent

053286 - Please Check Fault Codes in Transmission Control Module
U1026 - 000 - - Intermittent

Which might appeared after failure, probably when wife drained the battery trying to re-start. The thing that puzzled me some is that the touareg was running perfect the day before, we got that cold snap at -20c it died and after a week-end in the garage never came back to life.

One more detail... ECU has stage 1, DPF and Ad-Blue delete (no EGR delete), work very good since installation this past summer.

The fuel flow was not a precise excercise, only looking at return while cranking for unmeasured time to see what was coming out, filled a small container quite quickly.

When you say Check fuel pressure relief, fuel regulator, do you mean VCDS measure or physically?

Thanks,

 

[buckwheat]

A couple things that I would suspect. #1 is the fuel. If -20C is normal in your area this is probably not an issue, but if this is an unusual cold snap, the fuel might not be properly winterized.

The second thing that I wonder about is battery voltage and cranking speed. I don't have access to my car right now, but I thought they cranked in excess of 300 rpm. I am unsure of the minimum rpm for the 3.0L, but the 1.9 TDI has to crank in excess of 250 rpm in order for the ECM to fire injectors. Similarly, I don't have a lot of cranking voltages on the Touareg, but my other diesel vehicles crank at about 10.8 - 11.2 volts.

I may be able to get some of that data in a couple days if it's useful to you. What I am wondering is if you had fuel gelling, then the battery died, and the replacement battery may not have been fully charged. It's a long shot, but I've had stranger things happen.

 

[hedditch]

If you have not already done so, then take the cover off the fuel filter and check for metal filings. Sounds very similar to reported HPFP failures and the vehicle age is in the correct window for this problem.

Stuart...

 

[loujet]

Stuart,

I will do so, but just before, if hpfp would have failed, would I still be getting these numbers on vcds while cranking:

283.8 bar High Fuel Pressure (specified)
309.6 bar High Fuel Pressure (actual)

Thanks for your help!

 

[loujet]

buckwheat! I see you must get cold snap as well in your area!!

The Treg was in the garage after that for a while after the fail, I also added 5 gal of fresher fuel and a new battery, you are right it might noe be fully charged tough. I will put it on the charge right away.

If you ever get confirmation nothing happen below 250rpm on cranking even on 3.0l I'd appreciate, then it would be starter or battery issue...

Sorry guys, just noticed the thanks button on the bottom, I'll use it!!

 

[gazaflash]

Loujet,
When you were checking the fuel reg and you got 10 volts, was it the fuel retention valve? It should be at 10bar return pressure so that the Piezo injectors can operate properly.
Have a read of the attached training manual on that engine. It is very informative and will help you identify how the engine should work and all its code numbers for main assemblies. It is very useful for diagnosing problems. I am assuming that you have that 3.0 V6 model.

I just thought of another thing. Has there been any moisture/water around the battery areas? There is a fuel shut off relay (in case of accident) and main relay situated close to the battery compartment on the floor. If you had any condensation on the wires and/or connections, this might be the culprit?? You might have checked this already but I thought I would throw this into the mix too!

 

[hedditch]

Stuart, I will do so, but just before, if hpfp would have failed, would I still be getting these numbers on vcds while cranking: 283.8 bar High Fuel Pressure (specified) 309.6 bar High Fuel Pressure (actual) Thanks for your help!

Could very well still be HPFP problems as the damage is usually done to the injectors, so the pump may still be "working".

 

[loujet]

okay, opened the fuel filter canister, lifted the paper medium, paper was grayish, far from looking clogged. Spent time to look in detail, but at the end no way they were any trace of metal shreds. Then I took care to reassemble the cover and both seal in orderly fashion, got the hose from tank unplugged to see if by any chance it was not providing diesel... big mistake... filled about two empty wine bottles within "auto" prime was over (when you turn the key without pressing the brake pedal). Take two unplugged the fuel return from the hpfp, about the same volume comning out... So at the end I believe no diesel starvation is the problem.

I can see I am a little more clueless then I was!!!!!!

 

[dragline1570]

okay, opened the fuel filter canister, lifted the paper medium, paper was grayish, far from looking clogged. Spent time to look in detail, but at the end no way they were any trace of metal shreds. Then I took care to reassemble the cover and both seal in orderly fashion, got the hose from tank unplugged to see if by any chance it was not providing diesel... big mistake... filled about two empty wine bottles within "auto" prime was over (when you turn the key without pressing the brake pedal). Take two unplugged the fuel return from the hpfp, about the same volume comning out... So at the end I believe no diesel starvation is the problem.

I can see I am a little more clueless then I was!!!!!!

Ok so we have a diesel engine
It is just like the fire triangle if you have all 3 it will go
- Correctly timed fuel injection
- Compression
- Air


Based on you have ruled out HPFP issues.
Bleeding of the system.


I believe you need to check that the
- Injectors are getting signal to inject with a Noid light or like.(fuel)
- Check your throttle valve module to make sure it is opening (air)
- Unless you have had a major issue there would be no reason to be concerned with this. (compression)




Regards
Drag

 

[JimJ]

(when you turn the key without pressing the brake pedal)

Question
Does this procedure work in a 2008 V6 TDI, BKS motor?

 

[loujet]

should be able to perform this with a jury rigged tester, 12v lamp + proper connector should work I guess as a noid light? I will also check the throttle valve is functioning...

After the filter last night, this will be the agenda tonight...!

Tks all for your support!

JimJ, it should be standard issue, when you turn the key either with foot on brake pedal or not, it activate both low pressure fuel pumps, it runs for about 15 sec if brake is not pressed or for the duration of cranking in the other case.

 

[loujet]

I jury rigged a 12v light on one of the injector connector... it does not light on cranking. Not 100% sure on the value of my set-up but at first sight I do not think there is power going to the injectors. I checked all the fuses in the driver side plenum, it think one fuse in there is for the injectors, they are all ok.. any relay to look for??

 

[loujet]

Throttle body flap moves freely and it is clean as well.

Re-did the injector signal from the connector test three time with a 12v lightbulb, a voltmeter and another 12v led light. No sign of power at all. Checked all fuse in the driver side plenum and all good (I think one fuse in there is for injector signal)

So few things sorted out but the nothing starting... I now know what to ask for x-mas!!!

 

[dragline1570]

Well that's a step forward. Good job.


Identified one side of triangle missing.


Correctly timed injection or in this case no injection at all it seems.


regards
Drag

 

[loujet]

just did a one by one unplug injector / crank to see if one defective injector was telling the ECU not to send any signal to all six injectors... still no sign of life...

 

[loujet]

correctly timed injection, crank shaft position sensor... what to look for? vcds check?