Nissan fuel problem

Tony, could you be a bit more specific about the engine. 2.8 litre, 3 litre, 4.2, or 4.2 turbo for any trouble shooters.

If it is a 4.2 check screen in the banjo fitting at the fuel injection pump.

Its a gq ute but has a new 4.2 turbo diesel engine from a later model, not sure which.
The old engine was very sad and may have been suffering the same problems but hard to tell it was very very sad anyway. just done the heart transplant and it runs like a mongrel, it was perfect in the old vehicle so i dont think its an engine problem. if I get some one to continiously pump priming pump it runs well and no missing. seems to have problems sucking fuel to the injector pump but no sign of a blockage back to tank
Cheers to all
Tony

Definately try the gauze filter under the banjo fitting on the injector pump. I spent months with a problem that no so called experts could correct as they all insisted that there was no filter fitted to my GU 4.2 TD and I beleived them as I had checked for one but there did not appear to be one fitted. In the end I decided that there must be something blocking fuel flow in that area and after removing the the banjo bolt and small spring put a cotton bud down the hole and bugger me, out came a well and truly dirty filter. Cleaned it and reinstalled and almost the end of the problem. Vehicle ran well for almost a year in which time we towed a van around Aust and only three weeks ago the problem resurfaced. Straight to the filter and again part blocked with gunk. It is actually the coating off the washers each side of the banjo fitting and if you have that type the replacement part number is 16794-10G00. Nissan actually supply three different washers under different part no's. Good luck.

Had the same problem with a Triton diesel. Did all the blowing etc etc and finally after took off one of the short bits of rubber hose on the line to the tank and found that it was separated and a flap of rubber would come down and block the pipe. It just acted like a valve. The mechanic that discovered it had the same problem previously.
Its a long shot but it certainly sounds like fuel starvation.

Neil

Tony,
I've had the same symtoms on 2 occasions; firstly with my GQ back in the 90's and secondly with my current GU. Totally different problems so I'll describe both......

The GQ.......I had a Brown Davis long range tank which developed a small hairline crack. When I got it welded up, I reckon the bloke must have done the job with the tank still fitted to the truck. The crack was near where the fuel pick-up point was and the heat from the welding managed to melt the nylon base plate that the pickup tube sat in, causing the tube to be unable to suck up enough fuel for the motor's requirements.

The GU......I have a CAV filter adaptor where the normal filter is. The Denco unit will not take certain types of CAV filter.....you must use the ones with a solid tube down the centre. I had fitted a New Holland filter and it had a series of "bumps" in the top side which prevented it from nipping up tight against the large "O" ring. I could start the GU and drive at just above idle, but as soon as I put the foot down even a little bit, she'd just die. So, I guess the lesson there is to make sure there is no chance she is sucking air through a small crack in a hose etc.

Incidently, I've recently fitted a small, low pressure FACET pump half way along the chassis rail, so it sort of force feeds fuel up to the filter and eases the job of the main fuel pump. It only pushes 3 - 5 psi but that is enough to ensure that any small issues are covered. When it was fitted I discovered another small air leak in the bottom of the glass bowl where the bolt that holds the filter assembly together goes through the washer.

Good luck

Roachie

If these symptoms were happening with old engine and now with new engine (that was running fine in another vehicle), it seems to point not towards the new engine but something in or on your truck before the heart transplant. Blockage in the air intake, crap air filter?? or a rag that you forgot to remove ect ect.

Having said that if symptoms go away when you manually prime the fuel pump, like you said, it does sound more like a fuel starvation problem. But I'm only a backyard butcher when it comes to mechanicals, so more powers of deduction than mechanical diagnosis.

Hope this helps.
Trevor.

Thanks for all the ideas but no luck yet, not sure if the old engine was suffering the same problems as it has been in bad shape for a while now. The ute is a local farmers and I had it to install a shower and have now returned it. We tried all the tips above and makes no difference but i am convinced that it is a fuel problem, we tried removing the air filter and have replaced the fuel filter. we had another suggestion to bypass the fuel filter temporarily and to adjust the fuel mix screw, so will try this tomorrow. Im a backyarder myself and especially when it comes to nissans. any help on fuel mix adjustment would be appreciated, we found a loose lock nut on what we think would be the fuel screw but only seems to adjust the idle
the said screw is just above the injector lines on the pump body but was getting dark so will look further tomorrow.
Thanks again for all suggestions and hope tomorrow will bring a better result
Night All
Tony

Somethink I heard years ago with solid fuel lines on a tractor was that there was a coating inside the fuel line that only manifested itself to cover the line when it was under pressure. A flap closed off the line but wasn't apparent when forced the opposite way. I wonder if there is a bubble in rubber somewhere?

Tony

As a test you get a small drum (a ltr or 2 at most) that you can positively connect a fuel line to. Connect this to where you filter is in the engine bay and set it so it's a foot or two above the motor to supply a positive head to the injector pump. (positive connection no leaks) make sure you pull the power wire to your in tank fuel pump and and give the engine a run. If all is well you know where to go looking.
You can also lead the tank supply from the engine bay to a drum and turn it on. There should be a published volume per time in the work shop manual.

Fault finding oh what fun.

Jugs

Hi all
Today we installed an electric pump in the line prior to filter but once again made no difference to the running at all. we also installed a boost guage to the vehicle and i was surprised to find good and constant boost presure as i had felt that if the engine was starving for fuel that boost would have declined, no fuel ,no bang, no boost. power down low is good but nothig above 2000 and a miss develops above 2500 and seems to run out of steam. 3rd gear flat out just gets to 3000. have made adjustments to fuel screw but either way seems to decline.
Keep the thoughts comming
Cheers
Tony
ps no pump in this tank

Tony,
I had a Falcon years ago that would not go as it should (no power, leaking oil) so put in a new engine. The new engine would run but no power. Turned out to be a blocked muffler! Might be worth checking.
Regards
Scooby

I disconected the fuel filter completlyand replaced it with the electric pump, and checked for fuel flow at the injector pump inlet and has ample flow. it filled a coke bottle in about 30 seconds. the blocked exhaust is a problem i have had before but in this case it has a new 3" system from front to back
Cheers
Tony

Tony

Still thinking on this. My next step would be to run the engine at idle then crack each injector supply in turn and check all fuel no air and about equal amounts (very ruff) if this looks ok I would bring it up to where the miss is and repeat.

Looking for the injector cracked that did not change how the engine was running. If you find one it may be that you have a sticky injector or it has carbon build up on the nozzle this would stop or change the spray pattern. The other symptom for this is sooty or a puff of smoke at the exhaust (incomplete fuel burn).

The fact that if you manually prime the fuel line makes me think you have an fuel line sucking air or your low pressure fuel pump is not supplying a constant positive fuel pressure to the injector pump, if you have ruled out a restriction in the fuel line. It is less likely to be an injector as above as you can fix it by supplying manual fuel pressure

After that its off to the diesel mechanic

good luck
Jugs