PD fuel pump durability

[sharptdi]

How does the fuel pump in the 04 and newer PD TDIs handle increased loads put on the fuel system? How much extra stress can be put on it before it needs to be upgraded. I have a Cat 2 filter setup currently and I will soon have injectors and a fuel cooler. Will this be stretching the limits of the stock pump? I wouldnt think a typical fuel cooler would add too much restriction, but im sure it all adds up. Does anybody have a similar setup?
Thank you,
Walter

 

[Andrei Rinea]

You don't have a classic fuel pump in a TDI PD engine. You have 4 injector-pump units called Pumpe-Duse ("Pump-Nozzle" in German). You have a small low pressure fuel pump that draws fuel from the tank to the engine bay but this "tandem" fuel pump is electric and not very stressed. As for "injectors" I suppose you reffer to upgrade nozzles.

 

[sharptdi]

Thanks for the reply. I know the injectors are driven off the camshaft and do most of the work injecting the fuel, I was just unsure if the actual fuel pump (which runs around 15psi i believe) would be over stressed with these added modifications. I just wanted to make sure it could still reliably get the necessary amount of fuel to the injectors. Now that I think about what you said, it makes sense that these modifications wouldnt put that much extra load on the pump.
Thanks for the help,
Walter

 

[Long_Range]

Walter: You have an electric lift pump in the fuel tank. The tandem fuel pump is on the back side of the engine head driven off the camshaft. The vacuum pump is the other half of the tandem.


I don't understand a cool can in a diesel. Thought that was just for gas powered drag racers. Diesels like warm fuel. That's why their's a thermostatic tee in the filter to regulate the temp at 135[FONT=Arioso, cursive]°[/FONT] F.


If you want cooler fuel just bypass the tee. Not something I'd recommend.

 

[BioDiesel]

"I will soon have ... a fuel cooler. "

Just out of curiousity, what kind?
SVO users use heat exchangers, one of which is an Audi A8 fuel cooler.

 

[SUNRG]

You don't have a classic fuel pump in a TDI PD engine. You have 4 injector-pump units called Pumpe-Duse ("Pump-Nozzle" in German). You have a small low pressure fuel pump that draws fuel from the tank to the engine bay but this "tandem" fuel pump is electric and not very stressed. As for "injectors" I suppose you reffer to upgrade nozzles.

just to clarify, the tandem pump is not electric - it's the cam driven combination of a fuel pump and a vacuum pump.

a very cool feature of the PD fuel pump is "the fuel ducting system within the pump is designed so that the rotor always remains wetted with fuel, even if the tank has been run dry. This makes automatic priming possible."

their is a small electric lift pump located at the fuel tank in PDs, and this combined with the ducting design of the fuel pump gives PDs far greater run dry protection that previous models.

then you have the four unit injectors... so in all, there's a whopping 7 pumps in the PD-TDI fuel system - it is awesome, and immensely reliable and durable.

 

[danielttt]

then you have the four unit injectors... so in all, there's a whopping 7 pumps in the PD-TDI fuel system - it is awesome, and immensely reliable and durable.[/quote]

I must be missing something. I don't see 7 fuel pumps. Tank, tandem, + 4 injectors = 6. Is the vacuum end of the tandem related to the fuel system? Tryin to git edjikated. thx

 

[weedeater]

Automatics have a fuel cooler, at least the A4 did, under the passenger seat. Much residual heat is generated by the smaller pump on the auto. I wonder if the same is true on the PD.

 

[sharptdi]

Im looking at getting a Mocal oil cooler to use as a fuel cooler. They seem to have a good design and the 7 row unit isnt too big and should be fairly easy to mount. Plus this smaller unit will keep me from over cooling the fuel.
Very similar to this one

http://64.202.180.37/files/cool$.pdf?Submit1=Get+Pricing

I know that diesels tend to prefer warmer fuel, so I plan on setting up a switch that will let me bypass the cooler from inside the car when its cold and I have a full tank. My main reason for getting this is for when im at the track or somewhere and I would like to run 1/8 of a tank of diesel or less and not have to worry about fuel temps. I am also planning to experiment with this once I get a vag-com to see how the car runs with different the fuel at different temperatures.

Walter

 

[fitzski]

People reading this thread may also be interested in checking the following discussion (which was moved out of the PD forum for some reason):
Fuel pump noise?

 

[appman]

SharpTDI,
Don't you already have a fuel cooler? I have an 06 Golf (manual,A4) that came with one from the factory.

 

[sharptdi]

yes, there is a fuel cooler on the return line to the tank. This cooler uses engine coolant to cool the fuel, so it will not cool it below 190 deg. F. Its purpose is to cool the fuel enough to keep it from damaging the sending unit in the fuel tank. I want to install one that will cool the fuel before it goes to the injectors so that I can try to collect some data and see if the car runs better on warmer or cooler fuel.

 

[Dick_Larimore]

My 2004 Jetta TDI manual had a fuel cooler under the passenger seat, but it was a simple radiator using ambient air and some direct conduction of heat to the underbody of the vehicle. It did not use engine coolant for cooling. That cooler on the fuel return to the tank would get hot to the touch, but not 190°F.