Fuel priming pump

[frosty]

My truck still as a misfire am starting to wonder whether it could be fuel supply should the priming pump black button be solid to push?

 

[AlexD333]

if you mean on the filter? yes. If something else then I do not know myself :thumb2

 

[Fez_uk]

Could be filter, primer, crap in the fuel lines or swirl chamber in the tank.

 

[Lazy-Ferret]

My truck still as a misfire am starting to wonder whether it could be fuel supply should the priming pump black button be solid to push?

Yes...

The easiest, quickest and cheapest thing is to do to start is to replace the two flexible pipes to and from the filter with a clear pipe.

You can then look for bubbles in the fuel lines, which will help you fault find it.

Bubbles in the inlet, mean there is a leak in the feed to the filter, which is quite a common problem, as the fuel lines corrode on these, specially where they pass over the real axle. Also the small flexible pipe that connects the fuel tank to the pipe also goes hard over time, and splits.

Bubbles in the outlet point to the filter not sealing, or the water trap under the filter leaking, or not properly closed, or as in my case, the actual cast housing had a split where the input pipe went it, and it was drawing in air through there.

 

[dave123]

Yes...

The easiest, quickest and cheapest thing is to do to start is to replace the two flexible pipes to and from the filter with a clear pipe.

You can then look for bubbles in the fuel lines, which will help you fault find it.

Bubbles in the inlet, mean there is a leak in the feed to the filter, which is quite a common problem, as the fuel lines corrode on these, specially where they pass over the real axle. Also the small flexible pipe that connects the fuel tank to the pipe also goes hard over time, and splits.

Bubbles in the outlet point to the filter not sealing, or the water trap under the filter leaking, or not properly closed, or as in my case, the actual cast housing had a split where the input pipe went it, and it was drawing in air through there.

how does that work in my case ?. I had air bubbles in the inlet pipe just before the filter . so I changed my pipes from tank to engine bay and checked the rest of the pipe nice and clean with no rust or dirt or niks / splits on them but I still get air in the inlet if I leave the car over night?.

 

[Lazy-Ferret]

how does that work in my case ?. I had air bubbles in the inlet pipe just before the filter . so I changed my pipes from tank to engine bay and checked the rest of the pipe nice and clean with no rust or dirt or niks / splits on them but I still get air in the inlet if I leave the car over night?.

That was what happened to me... the fitting that the flexible pipe goes onto, on the input side, is screwed into the cast housing on a taper thread, and I noticed mine was loose, which I initially thought was the problem. When I tightened it up, fuel started to leak out the joint and when I looked closely, I could now see there was a small split in the casting along the bottom of the thread. Before I messed with it, it must have been allowing air in, but not much fuel out, but when I messed with it, that was enough to open it up enough to allow fuel to leak out more noticeably.

 

[Banshee]

Take it from a man who knows that that's deffo fuel starvation. Under normal circumstance the primer plunger on top of the filter head should be solid and firm however should be depressable to an extent, under no circumstance should it be sucked down as this would indicate a blockage in the fuel system somewhere.

As already said, first thing to do is replace the feed and return on the bulkhead to the fuel filter with 8mm ID clear plastic piping, this will then allow you to see any air bubbles in the pipes which would 100% confirm a blockage.

Check the state of your fuel lines all the way down the car and ensure that there are no rust holes letting air into the system.

Mine turned out to be crud in the swirl chamber of my pickup in the fuel tank, connifer nettles, leaves etc see this thread;

Plenty in depth pictures of the issues;
http://www.nissan4x4ownersclub.com/forum/showthread.php?t=22418

 

[marti666]

this may sound stupid but have you checked the mini filter (if you have one) as I believe it's the smallest id point prior to the engine in the fuel line.... :nenau

Martin

 

[Sweety]

this may sound stupid but have you checked the mini filter (if you have one) as I believe it's the smallest id point prior to the engine in the fuel line.... :nenau

Martin

You beat me to it:lol

 

[marti666]

You beat me to it:lol

All we need now is Briggie to mention the .......... and we may have all possible causes.....:augie:augie

 

[frosty]

there isn't a mini filter on mine, and yes if I force the plunger down it will move. I will try clear pipes to see but this is doing my head in!! sometimes its worse than others but am certain its slowly getting worse, only time it doesn't do it much is when I give it some welly up around the 4000 to max revs, then it does run better for a few miles.

 

[Banshee]

there isn't a mini filter on mine, and yes if I force the plunger down it will move. I will try clear pipes to see but this is doing my head in!! sometimes its worse than others but am certain its slowly getting worse, only time it doesn't do it much is when I give it some welly up around the 4000 to max revs, then it does run better for a few miles.

that's the exact symptoms mine had!!!! Turned out to be the swirl chamber

 

[frosty]

Thanks banshee, i think I will start with taking the sender unit out and see what's going on in there, only difference with my truck is that there doesn't seem to be any fuel starvation, it goes straight up to the red line, even pulling the caravan there's no pulling back as though its struggling for fuel.