What do you do if your TDI runs out of fuel?

seafarer28 · Jun 22, 2011

Did a number of searches but couldn't find a post on the subject......how do you restart your diesel after it runs out of fuel?

If this topic has already been discussed or if there is a DIY thread on the subject please point me to it, if not how DO you go about it.

Thanks, Tony

SamTrooper · Jun 22, 2011

The air needs to be purged out of the system, on the older tdi's you could just crank until they start, the new v6 tdi doesn't apprciate that at all, You'll probably need a dealer for this one.

OILSLURPER · Jun 22, 2011

My experience with low fuel light 'on' is to fill up when it comes on. The fuel tank indicator is not accurate relative to fuel remaining when the light comes on. Does not answer the question other than don't let it happen (running out of fuel).

Str3t · Jun 22, 2011

Never run out of gas in my life...but good to know this is a reall no-no w/ the TDI. Thanks.

conrad787 · Jun 22, 2011

you can drive almost 700 miles on one tank of diesel. there's really no excuse to ever run the car until the tank is dry.

Biff · Jun 22, 2011

conrad787 said:
there's really no excuse to ever run the car until the tank is dry.

Unless the economy tanks out and makes necessities scarce to come by.

seafarer28 · Jun 22, 2011

Agree that we "shouldn't"[-X run out of fuel but reality is that one day someone somewhere will, what DO we need to know and do when that happens?

volkswagendude · Jun 23, 2011

Ya, never run out of fuel no excuse....to those who just lectured, thanks for the heads up

.

In any case, if you do a DIY on the fuel filter replacement, you will have the same issue anyways, well at least I did. On my Passat TDI, I believe it makes mention of the starting procedure in the owners manual interestingly enough.
You simply turn key, and crank non stop, and it may take up to a minute worst case scenario.
I had the same issue on both Passat and my previous Golf TD. Took about 30 seconds of non stop cranking, so be brave.

SamTrooper · Jun 23, 2011

The cranking works well on the Pre-common rail TDI's. However, I would NOT recommend doing this with the Current Common rail 2.0 TDI's or 3.0 TDI's. The bently explicitely states for the Jetta not to dry crank/prime the engine when doing a fuel filter change. This can damage the very sensitive pump which is lubed by the fuel pumped through it, and even a few seconds can be enough to destroy it. I am assuming the 3.0 CR TDI fuel pump, is similar even though it's a 2 plunger vs a 1 plunger design. According to the Bentley manual, when changing a fuel filter on the newer tdi's, you MUST prime the fuel system via Vag-com 2-3 times before attempting to start. I would not try a dry start, or even a PRIMED filter(with ur fav fuel addtive), unless you've primed it several times before you turn the key.

The Cranking works fine for previous diesels, I have a 1.9 tdi, and had many previous diesels doing this no problems, but due to the higher lubricity requirements, and lower tolerances for dry diesel fuel on the CR tdi's, I highly recommend against dry cranking in the new 3.0 TDI or 2.0 TDI. For further reference run a search on TDIclub.com

OILSLURPER · Jun 23, 2011

SamTrooper said:
but due to the higher lubricity requirements, and lower tolerances for dry diesel fuel on the CR tdi's, I highly recommend against dry cranking in the new 3.0 TDI or 2.0 TDI. For further reference run a search on TDIclub.com

I haven't looked into this, but diesel is still light refined oil and it does have lubrication properties. You'll know that in a practical sense because you get the stuff on your hands at the bowser and its oily. So, it's probably to some truth about the fuel in the pump lubricating the mechanism. I'd not run the pump dry....not ever.....ever! If you did, you wear any cost for potential damage. Plan the trip and ensure you know when to get fuel. The TDI has the legs, so there's no excuse you run the tank dry. Prevention is better than the cure. Next time you fly, just remember your aircraft captain works on this practice.

Laggyband · Jun 23, 2011

This following is direct from Elsawin and is the proceedure for the 3.0tdi BKS engine:

Bleeding fuel system
After installation, the high-pressure pump must first be filled with fuel before the engine is started (the pump must not be allowed to run while still empty).
Note
t When installing the high-pressure fuel pump, it is essential to ensure that no dirt enters the fuel system.
t Only remove sealing plugs immediately prior to installation of fuel pipes.
t There must be sufficient fuel in the tank.Bleeding fuel systemProceed as follows to fill high-pressure pump with fuel.
tConnect battery charger if necessary → Electrical system; Rep. Gr.27.–
tUnplug connector from fuel pressure regulating valve -N276- so that engine does not start when starter motor is operated.–
Operate starter for 3 x 13 seconds. (Wait approx. 20 seconds each time after operating starter to prevent it from overheating.)–
tRe-attach connector on fuel pressure regulating valve -N276-.–
tClear fault in fault memory using diagnostic tester → Chapter.–
tStart the engine.–
tAfter bleeding fuel system, leave engine running at moderate speed for a few minutes and then switch off again.–
tCheck fuel system for leaks → Chapter.–
tObserve applicable safety precautions during road test → Chapter.–
tAfter completing the repair, road-test the vehicle over a distance of at least 20 km. Accelerate with full throttle at least once.
tThen inspect the high-pressure section of the fuel system again for leaks.
Note
If there is any air left in the fuel system, the engine may switch to the backup mode ('emergency running' mode) during the road test. Switch off the engine and clear the fault memory → Chapter. Then continue the road test.

Laggyband · Jun 23, 2011

Schematic overview of fuel system (engine codes BKS, BUN)

1 - Fuel metering valve -N290-q Do not unscrew.
2 - High-pressure fuel pumpq With gear-type pre-supply pump.q High-pressure pump generates fuel pressure up to 1600 bar.q Gear-type pre-supply pump generates a fuel pressure of between 4 bar and 5 bar.q Removing and installing → Chapter.
3 - High-pressure accumulator (rail element)q Cylinder bank 1.
4 - Fuel pressure regulating valve -N276-q On cylinder bank 1.q Removing and installing → Chapter.
5 - Fuel pressure sender -G247-q On cylinder bank 2.q Removing and installing → Chapter.
6 - High-pressure accumulator (rail element)q For cylinder bank 2.
7 - Injectors (piezo injectors)q Injectors 1…6.q Removing and installing → Chapter.
8 - Fuel return lines (from injectors)q The fuel return lines must not be dismantled; if necessary they must be renewed complete with pressure retention valve.q After replacement, engine must be run at idling speed for approx. 2 minutes to bleed fuel system. Then check fuel return lines for leaks.
9 - Pressure retention valveq The pressure retention valve maintains a residual pressure of approx. 10 bar in the return lines.q This residual pressure is required for the control function of the piezo injectors.q The pressure retention valve may only be renewed together with the fuel return lines.q After replacement, engine must be run at idling speed for approx. 2 minutes to bleed fuel system.q Checking → Chapter.
10 - Fuel delivery unit
11 - Fuel filter

So to summarise.
To bleed the system unplug the fuel pressure regulator on the end of the fuel rail and crank the engine for 3 lots of 13 seconds, reset the fault codes and take her for a blast.

Unplugging the fuel regulator will not allow pressure to develop so the pump runs load free in full flow

OILSLURPER · Jun 23, 2011

Laggyband said:
This following is direct from Elsawin and is the procedure for the 3.0tdi BKS engine: *_Bleeding fuel system_*After installation, the high-pressure pump must first be filled with fuel before the engine is started (the pump must not be allowed to run while still empty).

Workshop procedure for replacing the pump So, yes, good info from Laggyband. The bit of interest is the bold text I underlined. You run dry, then you pray you don't need to pay for it! If it's (the pump) has been run dry then it may be moot! I know from personal experience that the last 1/4 of the tank is not really a 1/4 tank. I nearly went empty towing my boat back from Port Macquarie last March. I pumped 93 litres into her and that was at 11.00pm. I was lucky I found a servo open.

hedditch · Jun 23, 2011

I realise this doesn't answer your question Seafarer, but one area of concern with high pressure "Common Rail" fuel systems is the amount of heating of the fuel. I have a some mates who run heavy interstate trucks and they all say you should never let your fuel level get low if you can avoid it, as it leads to heating problems with the fuel as the excess fuel from the common rail is returned to the fuel tank and the less fuel in the tank the less cooling occurs. I know the V6 TDI has a post cooler on the return line , but it is a point worth considering. I have been told that high fuel temps will impact the fuel pump and associated equipment.
I am not a diesel mechanic, but it makes sense to me..

Stuart...

SamTrooper · Jun 23, 2011

I suggest anyone interested in Changing their fuel filter, read this article.
Fuel filter replacement location and change for 2009, 2010,2011 VW Jetta TDI or VW Golf TDI
The process of priming the fuel system with vag-com should be the same on the current v6 tdi engine code "CATA". I'd rather err on the cautious side and not damage a 10-15,000 dollar fuel system by allowing the pump to crank dry. As mentioned earlier, previous diesels have been oil fed and did not lack lubrication when they ran out of fuel. Laggly band has some good points, however those article explicitly state not to run the pump dry, i'm sure a good mechanic would use vag or vas to try to prime the system before starting it up. Why take a chance.

I have some of my own suspecions that some of the HPFP failures happening in some of the 2.0 tdi's may be related to fuel filter changes that arn't properly primed. Damage starts, however minor it may be, and down the road the whole thing falls apart.

noobytoogy · Jun 23, 2011

OILSLURPER said:
..... so there's no excuse you run the tank dry. Prevention is better than the cure. Next time you fly, just remember your aircraft captain works on this practice.

Most of the time.....

Passengers sue airline after jet runs out of fuel - Europe, World - The Independent

OILSLURPER · Jun 23, 2011

noobytoogy said:
Most of the time.....

Passengers sue airline after jet runs out of fuel - Europe, World - The Independent

Ah yes, the old, "sh1t happens". Always has, always will! There's some good points come up in this thread though. The caution is the cost of screwing up something that was otherwise not going to screw up, unless you (the owner) let it.kaboom

Laggyband · Jun 23, 2011

OK i went to the section "What if you put petrol in by mistake and crank the engine", as surely after that you would have to bleed the system from an empty tank and it referes to the above proceedure:
Procedure for 2nd case–
Empty fuel tank as far as possible via fuel filler neck using fuel extractor -VAS 5190- → Chapter.
– Remove rear seat bench → General body repairs, interior; Rep. Gr.72.– Remove cover from fuel delivery unit Note
Press in securing ring to release fuel line.
– Pull fuel supply line (blue or blue marking) -1- off fuel delivery unit.
– Connect -VAS 6550/1- pressure tester line to fuel return hose -1-.
– Guide open end of line into a suitable container.
– Connect vehicle diagnostic tester and perform the guided function “Emptying fuel system”.[ Note
The fuel pump is now activated.
– Repeat procedure until fuel tank is completely empty.
– Remove fuel delivery unit and check fuel tank for soiling and metal particles → Chapter.
– If necessary clean fuel tank and reinstall fuel delivery unit.
– Fill fuel tank with 5 litres of diesel and drain it using guided function “Emptying fuel system”.
– Renew fuel filter → Chapter.
– Renew following high-pressure components:
t High-pressure pump → Chapter
t High-pressure lines → Chapter
t High-pressure accumulator (rail) including fuel pressure regulating valve -N276- and fuel pressure sender -G247- → Chapter
t Injectors (piezo injectors) → Chapter
t Fuel return lines (leak oil lines) → Chapter

– Reconnect fuel return line (blue or blue marking) -1- to fuel delivery unit.– Fill fuel tank completely with diesel.– Fill/bleed fuel system using guided function “Bleeding fuel system”.– Carry out a road test.

Laggyband · Jun 23, 2011

The system is like a hydraulic system, the pumps in the tank will be high flow low pressure to supply fuel quickly to the high pressure pump, so within 1-2 seconds of the initial crank fuel wil already be running into the high pressure pump, through it and back to tank.
The high pressure pump has 3 lines attached to it, one is from the high flow low pressure pump in the tank (Supply), one is the high pressure low flow line to the common rails(Delivery), and the other is a return to tank. (Case drain/bleed line which i assume is at the highest point)
The tank pump merely primes the lines & high pressure pump and provides optimal suction conditions for the high pressure pump (Positive suction pressure).

Laggyband · Jun 23, 2011

I like to publish as much Touareg info on line as possible as this website will then become an online source for future Touareg owners.

What do you do if your TDI runs out of fuel?

seafarer28

SamTrooper

OILSLURPER

Str3t

conrad787

Biff

seafarer28

volkswagendude

SamTrooper

OILSLURPER

Laggyband

Laggyband

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OILSLURPER

hedditch

SamTrooper

noobytoogy

OILSLURPER

Laggyband

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