1987 Nissan PU fuel pump question?

[subwar2001]

Does the SD25 model sold in Canada actually have a fuel pump. I cannot find if there is one in the tank according to the wiring diagram. Just curious about this as I just changed the fuel filter. I hope the spider covered in fuel came from the outside and not from the filter.

[plenzen]

It does have a "fuel pump" (injection pump) but I think you are asking if it has a separate "lift pump" to get the fuel from the tank. It does not. The injection pump has the “lift pump” built into it and it draws fuel from the tank, through the filter(s) and then injects it. The black push button/plunger on the top of the filter housing will assist you in drawing fuel from the tank when the engine is not running and will allow you to bleed air from the system after you have changed the filter(s). There is a small 8mm plug just to the left of that plunger on the housing that you remove to allow the air to bleed out. Be careful you don’t lose the tiny fiber/copper gasket that goes around it. An easy way to tell if you still have air in the system is to tighten that bleed plug and press on the plunger. If its rock hard there is no air, if spongy it still has some. If the engine will run let it idle for a few minutes and then check that plunger again. If there is air the idle will be rough and the engine will shake etc. Once it smoothes out check the plunger again. You may have to take it for a bit of a drive and then check again. You may feel the odd "miss" but the system will "self bleed" itself eventually.

HTH

Paul

[subwar2001]

Thanks Paul

Due to the fact that my priming pump seems to be not working, I eventually had to loosen the injection lines at the injectors until there was no air left and then it settled down

[davehoos]

gas 87 D21 has an electric fuel pump option.its inside the fuel tank.
some dont have an electric cut off so if ignition is on it runs.

basic gas models have mechanical pump, and ive come across vehicles with both.electric pump has a non return valve setup-when you suck more fuel than the pump suplies fuel can shut off.

fuel tank sender unit will have 4 wires if it has an electric pump.

87 SD25 will have VE injector pump with internal lift pump.

[asavage]

Just so we're clear: it's only the gasoline trucks that have electric fuel pumps.

The diesels don't. The inline has a separate lift pump on the side of the main IP, and the VE-style (distributor, rotary) has an internal vane-type feed pump that sucks the fuel. Yours should be a distributor type IP.