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View Full Version : Intermittent fuel issue - IIA/2.25 petrol/weber 34ICH/mechanical fuel pump



cgalpin
04-30-2012, 12:47 PM
To avoid hijacking a related thread on warm start issues, I will start one for an intermittent fuel issue I have been having.

The truck always idles great, starts right up (unless warm start after a short stop, see http://forums.roversnorth.com/showthread.php?13373-2-25-Petrol-Weber-Carb-Slow-Start-When-Hot&p=84690#post84690).

However, in a seeming random fashion it will go from running great to having no power without the choke all the way out. By no power I mean even in neutral if you blip the throttle it will stutter like it's not getting fuel. I have noticed that it can start happening by simply hitting a bump (my springs are rusted/stiff and the rear will bounce easily). It can last a long time in either state, or switch back and forth relatively quickly like in alternating trips).

It will seemingly randomly self correct as well. Just recently I was idling or at near idle for a few minutes while my daughter was practicing parking, and although it had been in the "choke on" mode up until that point, I tried without it and it was fine. Not sure when exactly it self corrected but it did.

Because it is intermittent I am hesitant to blame the carb, although I have a rebuild kit and if it comes to it I'll rebuild it. It has a generic Purolator filter right before the carb and I recently replaced it but the problems still occurred after. It's the clear kind and usually it sits about half full. The old one looked well used but no obvious signs of dirt in it.

The truck is running fine at the moment, but while doing other maintenance I did notice a bunch of crap in the fuel pump sediment bowl which I have since removed.

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If you have any idea what the yellow looking material is, please let me know.

Other than inspecting the tank for issues, does anyone have any suggestions?

TIA,
charles

yorker
04-30-2012, 12:55 PM
That really looks like you might be losing the lining in your tank(if it has been lined with something like Kreem). Or someone filled the tank with a jerry can that was losing its lining some of them had a cream colored lining.

cgalpin
04-30-2012, 01:17 PM
Thanks, I'll check out the tank sometime. Any advice on the best way to do this? It looks like the only decent sized hole is the filler neck, so I'll need to drop it to get a good look. The fuel level gauge hole might be big enough to get a peek in I guess.

yorker
04-30-2012, 01:33 PM
you can peek in the pickup tube hole or the gauge float hole too. They would be easier.

cgalpin
04-30-2012, 01:44 PM
The pickup hole looked tiny and I didn't want to disturb the gauge since it all works so well right now :) I'll do the gauge hole I guess.

giftshopduane
04-30-2012, 02:24 PM
That really looks like you might be losing the lining in your tank(if it has been lined with something like Kreem). Or someone filled the tank with a jerry can that was losing its lining some of them had a cream colored lining.

+1

Good luck getting it cleaned out, if it's the case I'm not sure how its done. New tank cheap from RN. It certainly would explain a lot.

jonnyc
04-30-2012, 09:24 PM
Take the whole pick-up tube out and see of there is a screen on the tip. It might need cleaning, as well as flushing out the tank. Is there a drain at the bottom of your tank? If so, I would drain and flush it out. I've never seen that much crap come out of a tank before.

stomper
05-01-2012, 06:12 AM
As others have said, peek in through the pick up tube hole with a flashlight. drain the tank, and see what you have left. Some people have had good luck with droping the tank, and placing a chain inside. then just shake the tank until you are exhausted. Clean and refit.

cgalpin
05-01-2012, 07:40 AM
Thanks guys

Yes I'm definitely going to have to do this but it might be a couple of weeks before I get a chance as I have to finish up work on my defender first and want to have one running while I work on the other.

But my problem came back yesterday. Not 100% sure if it was the reason, but it was at highway speed on a bumpy section of road, so it certainly sounds like it's crap in the fuel.

I'll let you know once I get back to it.

martindktm
05-01-2012, 08:04 PM
HAve you opened the top of the carburator to clean the bowl inside? Weber 34ich has his main jet at the bottom and can get dirty pretty easy.

Partsman
05-01-2012, 09:40 PM
HAve you opened the top of the carburator to clean the bowl inside? Weber 34ich has his main jet at the bottom and can get dirty pretty easy.

This is true, and if you're sucking junk out of the tank, it can certainly be a major contributor to your problem.

cgalpin
05-02-2012, 06:28 AM
No, to be honest I have been hesitant to open it up as I don't want to make things worse :). I did pull the idle jet and check it.

When my defender is back on the road I'll bite the bullet and open it up as well as check the tank. No point cleaning the carb if there is still gunk in the tank.

I am not sure how much fuel you would normally see in the filter but yesterday I checked the level before starting and it was extremely low. But it started right up and even after idling for a bit the level didn't increase. I assume this indicated a clog somewhere downstream, or the pump failing. But as I said it was running in it's poor state and even blipping the throttle the engine stuttered. I revved it up good and proper a few times and it cleared up. Mid way through a short trip, she started running poorly again which I guess means gunk making it to the jets again :)

ghettoct
05-02-2012, 08:25 AM
i had a similar problem with my ex-mod 109, it ended up being a partial occlusion at the pickup tube, fuel line connection on top of tank, took the fitting off and had some rusty bits caked on, with a small hole that would occasionally clog and cut fuel off, when i shut engine off the hole would open or clear just enough to start and run but when i got up to 55 mph it would suck it close and starve fuel.

tank is now clear for most part but my pick up tube had no screen on allowing small rust up. took a pick up tube scren off an old mustang sending unit and put on end.

good luck on your fix.

cgalpin
05-14-2012, 07:32 PM
Well, I looked in the tank and although there was some rust, it had nothing like the stuff I found in the fuel bowl (it is not lined), and the fuel was crystal clear. I pulled the tank anyway and shook a chain around in it for a bit. Admittedly the only chain I had was rusty so I think most of the rust came off it, but the exercise did produce some rust. I was amazed that the fuel I used to rinse it with never cleared and the rust has remained suspended in it, even after several days.

I really don't think this is the cause of my problem and don't want to try line it or anything right now. There is no filter on the pickup tube but I don't think there is room for one either. I'll check the right angle joint where the plastic tube fits and make sure it's clear next, otherwise I'll look to the carb next.

Could my fuel pump be failing?

Here is what my tank looked like prior to cleaning

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And this is after. It doesn't look any better, I know :)
6409

SafeAirOne
05-14-2012, 08:19 PM
As rusty tanks go, that one's not too bad at all.

yorker
05-14-2012, 09:08 PM
I'd put a sock on the pickup tube, they are usually made of saran and can help filter out water plus the holes are so small they actually help prevent fuel starvation when you tip or go around the corner with low fuel in the tank. If nothing else I'd get a run of the mill fuel sock, cut the metal part off and fix it to the Land Rover pickup tube with mechanic's wire. It is your first line of defence against crap in the fuel system. http://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l2736&_nkw=fuel+sock

cgalpin
05-15-2012, 07:10 AM
Good advice, thanks.

J!m
05-15-2012, 08:14 AM
Good advice so far, but I will chime in a few details I have gleaned over the years (even though my series is now someone else's problem).

Stating at the tank, it looks very clean. Since it is off and clean, get some tank liner stuff. I have used the POR-15 stuff as well as stuff my company sells that is essentially the same stuff.

Next, the pickup. I actually replaced mine with a piece of copper tubing (it doesn't rust!) that I made a bit longer, to reach the last drops of fuel (and tank sludge). The lined tank is critical for the (lack of) sludge part. You don't want any. The screen is not a bad idea, but the sediment bowl does a fair job getting the 'big chunks' out. Make sure your filler neck still has the extension with the screen in it, so you are not adding any dirt to the newly cleaned system...

Another often overlooked detail is the fuel cap. Did you get a new oner? If so, it is a series III one, which is non-vented. Even on series III restorations, the vapor recovery stuff is usually in a land-fill somewhere... You need to drill a 1/8" hole in the inner lining of the cap (where the chain attaches) if you have a new cap. This vents it, and the venting is critical! Non-vented it will create a vacuum and not allow fuel to flow. The vacuum will dissipate over time, so starting it 'cold' is not a problem, but after it has consumed fuel for a while the vacuum comes back...

Now we move to the hoses. I assume you will replace the pickup and gage gaskets (they will leak) but make absolutely sure the hoses for the fuel are tightly fitted and securely clamped. I had a slightly (and I man slightly) loose clamp at the tank pick up and it allowed air in the line. With that tiny leak (fuel didn't even leak out it was so small) the pump had trouble priming and caused fuel starvation problems. I discovered this AFTER I rebuilt my fuel pump...

At the pump, make sure it is mounted securely. Loose bolts cause lower cam action (less pumping) which is a clear problem. Bowl gasket should be clean and soft. Get a new one if needed and be sure it is sealed well (no air leaks!)

Moving up to your in-line filter, it will fill (or not) dependent on the float in the carburettor. When the carb needs fuel, it will be pumped up; when it is full, the float closes the inlet and the filter appears to do noting (like the fuel pump is not pumping). Again, all fittings need to be air tight.

Now to the carb. Webers are like Holley's: easy to set up; however you have to set them up often. Here's a free trick that I had to do fairly often... Pull the air cleaner elbow off the carb.
Get it running and rev the engine from under the hood.
Once up at a high rev, place your hand over the carb inlet and choke it until it is just about stalled (don't let it stall!)
remove hand and let it get back to a smooth idle again.
Repeat above 3-4 times until you are satisfied the idle is smoother and not getting any better.
Adjust idle and idle mix per carb instructions. You usually have to go back-and-forth on this a few times. And make sure you use a tach so you can accurately see what is going on- don't rely on your 'ear' no matter how god it is.

Finally, as the truck sits, the fuel drains back to the tank past the fuel pump. Some take longer than others. When I was driving the truck, chances were it was sitting for several months before I was trying to start it. Before I even tried, I popped the hood and primed the fuel in the carburettor with the priming lever on the fuel pump. You will see the fuel filter fill up and ten no fuel seems to flow after a time. When the fuel stops, the carb is full. NOW start it and it will start quicker and easier.

If hot starting is an issue, you can try to insulate the fuel lines with pipe insulation. Also, re-run the fuel lines away from heat sources as ,much as possible (exhaust, radiator, hot air from radiator etc.). The extra length is not a big deal, as the pump has to overcome the head (height to lift to the carb) and the length is not a huge issue.

cgalpin
05-25-2012, 09:07 PM
OK, I decided to pass on any kind of lining/painting of the inside of the tank. I did get a fuel filter sock and wire it on, thanks for that. I then moved on the carb since the problem did not go away. I wish I just hadn't been afraid to open it up because the problem was clear - junk in the main jet. I cleaned it out and it's back to it's old self again.

The reason I don't like to mess with stuff that works, is that invariably it doesn't afterwards :) My fuel gauge used to be very steady and now it floats, so I assume I didn't put it back in the exact right orientation. Does anyone know what that is, or could it be something else?

Thanks for the advice everyone.

yorker
05-26-2012, 07:41 AM
Yeah that is pretty typical of the Weber even with an inline filter you can get the jet plugged. Hopefully the sock will help.