new to diesel

[Urvey Member Find all posts View Profile Close Urvey]

Hi all,

I've recently purchased my first ever vehicle, a Nissan Urvan, DI, VE type IP and I'm having a little trouble trying to get my head around how the thing works. I scanned in this image from my service manual and was hoping that someone could answer a few questions I have about it.

1) a VE-Type injection Pump, that's rotary right?

2) Why does the return hose from the injectors go back into the IP before returning to the tank? Would I tee off the VO return/ VO return loop before or after where it re-enters the IP?

3)Why does my fuel filter have an electrical cable going to it?

4) I see no lift pump, I assume that means it does not have one. Does that mean that the IP would also be strong enough to not need a lift pump for VO? Is the best way to determine this to just add a pressure gauge just before IP?

Cheers for the help.

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: new to diesel

1/ your schematic diagram shows a rotary just like my toyota. Mine, I believe is made in Japan under license to Bosch. Yours is most likely same/similar.

2/ ...its a convenient place to connect the injector "overflow" so that it gets returned to the tank as well. It doesn't "re-enter" IP.
Best place to break into the return line would be somewhere after the banjo on the pump. You need a valve, like a pollak valve to direct fuel to either loop or tank. I use two individual valves for this purpose as I just happened to have them lying around. (They are reachable from driver's seat)

3/ Probably a water sensor. It will use a float to guage if any water is in the filter. Will connect to a dash warning light. My toyota had one.....they are expensive, especially if running vegie because filter clogging is a common reported problem.

4/ If it's a rotary pump, it will have its' own internal "rotary vane" lift pump. A vacuum guage is the go, just before IP and after filter. A high vacuum will indicate if the filter is clogging.

Hope this helps.

[Urvey Member Find all posts View Profile Close Urvey]

Re: new to diesel

Thanks Tbird,

It seems as if I've chosen the worst possible vehicle for a conversion, DI, rotary IP. Oh well, I better just to a dam good job of it. If I do destroy my IP, can I just replace it with an inline type?

What exactly is the banjo? I've been explained it before but I thought it had something to do with the filter and not the pump?

Also, I have a few more questions.
Where exactly do you tee off and then 'tee on' the coolant? Do I take it from the line heading for the heater and then return it to the line leaving the heater? or do I take it from between the engine and the radiator?

Is there a maximum length hose you can divert the coolant for? Either for pressure reasons or it just running out of heat? It seems like people sometimes use it for multiple heat exchanges as well as running it all the way to the boot and back. Is it still hot by the end?

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: new to diesel

The pump, if it's a Jap rotary bosch style, should be more than adequate. They are very tough and forgiving. Ideally you should run the vege at 80c, possibly thinning with diesel or petrol as well. It would not be an easy job to replace with an inline pump.....may as well forget that idea.

A banjo is a type of hose or fuel line fitting, that resembles the shape of a banjo. There will be a bolt going through it, fastened to the IP. Your filter may well have banjo fittings as well.

The water heating for fuel line should be before any onboard filter. Tee into the existing heater hoses.....(one tee in each heater hose). It will be the hoses running to and from the heater itself.

Hose length can be quite long, as the water pump has some considerable suction. Air locks can be problem but they usually work themselves out.

Hope this is of some help as it's quite difficult to explain some of the intricate parts and processes.