Fuel starvation, '92 TD42.

[yossie]

I'm new to the world of Nissans and diesel motors so I may ask the odd silly question, but I'd appreciate some help. I have recently acquired a '92 GQ Patrol, in very good condition, only 139K kms, but with ocassional lack of response when I want or need to accelerate hard. When the problem occurs, the response can be varied - ultra slow pickup, or pickup OK to a certain point then falls away sharply (with the kind of groan you might get if you were in a petrol vehicle and suddenly pulled the choke on full), or pickup OK then engine "missing" (like bad/dirty points or a cracked distributor lead might do in a petrol vehicle - for those of you old enough to remember cams, points and condensers!).

If I drive conservatively (which I do most of the time anyway) there's no problem. Only when I go hard on the accelerator, and I notice it mainly in 2nd and 3rd gear. I suspect that's because the higher gears don't cause the rapid increase in revs that you get at the lower gears, and so the fuel supply can keep up.

I've read forum posts about the main fuel filter (replaced, bled, last weekend), and the scintered wire filter in the banjo fitting at the front of the injector pump (checked - mine doesn't have one, might've been removed by previous owner?) and I even took the plate off the top of the fuel tank and checked the fuel pickup line to make sure there was no obstruction. I'm now looking at other potential problem areas.

Air in fuel line? - I notice that the priming pump on the main fuel filter will always take 5 or 6 pumps to harden up when the motor has not been running. Is this normal? Just today I parked for 20 minutes, facing up on a very steep drive. When I took off, I traveled about 50 metres and the engine then dropped to a rough idle, no response at all to the accelerator, and then evened out. To me, that lends weight to the idea that fuel in the line was able to run back away from the engine. Do these things indicate that the fuel line is dragging in air somewhere and possibly creating low fuel spots in the line? Could this starve the injectors under heavy acceleration?

The injector pump? - Am I right that this is the only fuel pump? Without any knowledge, I expected that there would be an electric pump up the back of the vehicle somewhere, but other posts I've read indicate that fitting an electric pump is something some keen people do - possibly to alleviate the problem I'm having. Anyway, at 24 years old and despite the low kms, could the pump be tired and not able to keep the fuel up to the injectors under heavy acceleration?

I look forward to any pointers and advice you people of the interweb can offer.

[MudRunnerTD]

Hi Yossie,

Firstly please head over to the intro section and post an introduction thread, we like folk to say g'day.

There is only the mechanical pump and suction. There is no electric secondary. The guys fitting the inline electric pump are chasing bigger HP generally out of bigger pumps starving. I doubt this is you problem on an unmolested car.

It could well be the pump but that would be unfortunate! Others might give you some tests to run.

Air in the lines certainly sounds feasible too. Do you have trouble starting it after it's been sitting for a few minutes? If there is air getting into the line between the tank and the pump the fuel will drain back and it will be a dog to start.

How does the Air filter look? Air starvation will present like this too.

[Cuppa]

Sounds like an air leak could be a possibility. Your description of taking off, faltering, & then coming good supports this. Vacuum in the line at larger throttle openings could reach a point where it's enough to suck air in, but not at moderate throttle openings. I reckon your pump will be fine.
Is there any difference in re-starting after the engine has been switched off for a short time compared to when it has sat overnight or longer?

A short story. On a previous vehicle (4 cylinder Nissan diesel) I had it would run fine a low to mid revs, but ran out of steam & could only manage 80kph flat out, whereas owners of similar vehicles reported a top speed of 100 to 10kph. I just thought they were exaggerating! When I then had what I thought was an air leak problem in the fuel supply line (it wasn't it was a sticky exhaust valve letting air in) I discovered a previous owner had fitted a non return valve in the fuel line, a not uncommon solution to prevent the 'loss of prime' caused by an air leak between fuel tank & pump. The problem in my case was that the non return valve was too small & restricting fuel flow at full throttle. Removing it gave me an increase of 20-25kph. Reason for the story - it is worth checking that you have no restrictions in the fuel line as well as checking for leaks.
FWIW leaks are not necessarily easy to see, if there is one a light dusting of talcum powder on the hose may reveal some dampness, but it isn't uncommon for air to be sucked in , but no fuel to leak out. Once access to the fuel line is achieved, it's far easier just to replace it with new hose.

But like MR suggests - check the air filter too.

[jff45]

Is it possible the little gauze strainer under the fuel line banjo is slightly clogged?

[Avo]

Is it possible the little gauze strainer under the fuel line banjo is slightly clogged?

check this first as it's easy to get at and is an easy fix,if it the problem

[Rossco]

Is it possible the little gauze strainer under the fuel line banjo is slightly clogged?
I think he checked and doest have one on the pump. Sounds like exactly what mine was doing. Mine was the pump but sounds like air getting in from somewhere could be the case too especially if it feels like its lost its prime. Could be the primer mechanism too letting it drain back as well.

[MudRunnerTD]

Is it possible the little gauze strainer under the fuel line banjo is slightly clogged?

It is not fitted. Has been checked.

[jff45]

Sorry, should have read it a bit better.
I wonder why someone would remove it from a low mileage engine. I've read of several cases where people were sure there was no gauze filter there but found it was a bit deeper than they first thought.
When I first checked mine I also thought there was nothing in there..

[Bushy674]

Early model TD42 didn't have a gause filter in the banjo fitting

[MudRunnerTD]

My 2005 GUIVTD42Ti did not have a Banjo gauze filter fitted, still doesn't. Never checked the GQ. I had very similar fuel Starvation issues with the GUIV a couple of years ago. Took 6 months to figure out and had lined up a pump rebuild, was a week away from putting it in to get done!!

Went and filled up the car then parked it in the sun at the supermarket, on my return I found a patch of fuel on the ground!!! First time it has ever presented!6 months of symptoms!! Turned out to be a split fuel line on top of my rear spring tower. Easy fix!!! Glad I didn't spent $2000 on a rebuild pump as it would not have fixed my problem!!

Mine would loose prime when sitting. If I sat on the side of the road idling it would stall when taking off too! Was a bastard!

[yossie]

Hi jff45.

Yes, when we removed the banjo bolt we expected the little mesh filter you referred to. When we couldn't immediately see or feel it, we cautiously went "fishing", eventually convinced there wasn't one there when we put a screwdriver down to the bottom of the well.

Yossie

[yossie]

Hi MudRunner,

There's certainly a difference on occasion in how long she turns over before kicking to life. Half-a-second versus about 3 seconds. But more like if she's been sitting for 20 - 30 minutes.
I checked the air filter today and its in good nick. Not one you'd look at and say it needed replacing.

I fitted a Ryco fuel filter (as recommended by the lads at Repco) last week as a first go at solving this problem. I was reading a post on another forum today, saying that the fuel delivery capacity of the Ryco filter is significantly less than the Nissan-branded filter because of the different micron ratings. Do you have any knowledge or view on this?

Yossie

[yossie]

Hi Rossco.

I am suspicious of the priming mechanism. Is it serviceable, or would I just replace it?

Yossie

[yossie]

Jeeez! Scared me on two fronts! Possible split fuel line and $2000 pump rebuild. I want my problem to be solved by an easily-replaceable $2 o-ring!

[Rossco]

Hi Rossco.

I am suspicious of the priming mechanism. Is it serviceable, or would I just replace it?

Yossie
Good question! I've never pulled one apart or know how serviceable they are. . . Hopefully others will know. .

[Kimbo63]

Hi Rossco.

I am suspicious of the priming mechanism. Is it serviceable, or would I just replace it?

Yossie
Hi yossie
Not a serviceable item but appears to be working ok if you can pump it up and it goes hard should be fine rare to see one on a trol fubar try pressurising the fuel line and check for leaks like mudrunner did but use compressed air or a small pump and block off one end might show up a leak as there is normally no pressure in there

[Cuppa]

As you are able to access both ends of the fuel line - suggest you just replace it. I reckon there is a 99% chance it'll solve your problem & won't cost much.

[MudRunnerTD]

As you are able to access both ends of the fuel line - suggest you just replace it. I reckon there is a 99% chance it'll solve your problem & won't cost much.

That is actually quite a task on a wagon. Most of the lines are steel. I woul take the end off the tank and the other end off the primer, block one end with a plug bolt and stick an air gun in the other end and pressurize the line then trace along with a hose in your ear along the fuel line looking for an air leak. If there is one it sounds like a small one. Mine used to take up to 15 seconds or more to start when it was at its worst, sometimes it would not start without popping the bonnet and priming again

[Cuppa]

That is actually quite a task on a wagon. Most of the lines are steel. I woul take the end off the tank and the other end off the primer, block one end with a plug bolt and stick an air gun in the other end and pressurize the line then trace along with a hose in your ear along the fuel line looking for an air leak. If there is one it sounds like a small one. Mine used to take up to 15 seconds or more to start when it was at its worst, sometimes it would not start without popping the bonnet and priming again


Ah, right. I was just thinking rubber hose. :1087:

[yossie]

An update on the fuel problem:

I consulted a fuel injection expert who took it for a drive and agreed that the problem was probably fuel constriction, possibly a blockage; and/or gunge caught in the leaf valve part of the primer pump letting fuel bleed back (like Rossco suggested, above). He thought I should try compressed air blast back down the fuel line, and clean the filter head (as much as you can!). Both of which I did. And it certainly improved the situation. The occurrences of hesitation and "flat" acceleration decreased - but still did happen. And I still had the hiss of air from the filter head after priming (not that my old ears could ever hear it, but the young blokes told me it was there).

So, still suspicious of the primer, yesterday I bought a $5 plastic in-line fuel filter and bypassed the primer/filter head altogether. SUCCESS!!! It's a totally different vehicle. Full-bodied, gutsy acceleration, no hesitation, no jerky flat spots. So having confirmed the cause, I'm now looking for a suitable replacement filter head - and I'm going non-Nissan and forget about the primer altogether.

[yossie]

Thanks to all for your interest and assistance.

[yossie]

BTW, the reason I'm going aftermarket for a new filter head is because a genuine Nissan replacement primer filter head is $337 - except there's none in the country. This info courtesy of Magic Nissan Parts, Melville WA.

I'd love to stick with the simple in-line filter, but those with more experience advise that I should have a filter capable of water removal.

[Clunk]

Have you tried Patrolapart or Nizzbits?

[Kimbo63]

There is one on fleabay here
http://www.ebay.com.au/itm/Fuel-Primer-Pump-for-Nissan-Patrol-GU-ZD30-3-0L-Turbo-Diesel-to-2007-16401-VC10D-/252293971653?hash=item3abde47ec5:g:RR0AAOSwsN9XBry-

And from patrolapart
http://patrolapart.com.au/product-search?criteria=Lift+pump&association%5B1%5D=

[Cuppa]

Cheaper option?
http://www.ebay.com.au/itm/8mm-5-16-Rubber-Bulb-Primer-/111937732030?hash=item1a10023dbe:g:s1kAAOSwh-1W6MvO

http://www.nissanpatrol.com.au/forums/showthread.php?36950-Fitting-a-CAV-filter-to-TDi42&p=670608#post670608

[nissannewby]

$145 aud plus postage from dubai with 20 in stock. (partsouq.com)

Even less from another supplier over there. (Carmarka.com)

[Ryank]

these gauze filters are a pain

[MudRunnerTD]

You will need a primer of some description mate as the fuel pump relies on vacuum. Noting that you had an air leak the fuel was basically draining back and the pump could not hold prime.

The primer is the same across the models I think and one from a wrecker will do, I think I have one off zd30 on mine after swapping it out looking for my fault.

Glad you found the problem.

Check out our Vendor for good aftermarket.

http://www.nissanpatrol.com.au/forums/showthread.php?37116-FiltersElite-*Super-Pricing-on-Filter-Kits-Oils-4wd-Parts-We-re-a-1-Stop-Shop!

[Bushy674]

Hi there! You may have it in your post but a fresh filter is always good insurance, checking all the flexible hoses in the fuel system is the go, eliminate the minor possible faults will fix s starvation issue 99 times out of 100. Best of luck!

[Bushy674]

Another point worth considering is that the Ryco filter while having similar filter paper has about half of the folds/volume of the genuine Nissan filter and will last a lot shorter distance especially if the state of the diesel tank is questionable

[Chris Riddle]

Yep, you need a primer and you absolutely must have a good fuel filter!! Any fines that get to the pump immediately start wearing it out. Pumps are very expensive!
Always remember, grease, oil and filters are the cheapest maintance you’ve got!
Cheers