Installing a Walbro pusher pump - update

[Chris]

TP that's pretty much the symptoms that I have been getting. Mine is 17 yrs old with 71 k on the clock. Age and miles are different ageing factors I think. You're right. Seals get hard with age and lack of use it would seem. Where as a CV sitting for years would probably be a good thing. My bottom swivel bearings were actually corroded in such a way that the steering actually indexed in the eroded places. However, 8 years less bum in the driving seat was a good thing. Liftio pumpitis seems to be a common ageing symptom.


Chris

 

[Matt Wright]

Excellent post Hope you took some readings on mileage this weekend you can share. Got under 17mpg in the 90 I have not cool!
Ruby is raring well at 20mpg+

 

[Chris]

Going to Wales the other week (all up and downy twisty and bendy) and got 21 mpg. That was with very old ATs on. Going to Scotland this weekend cruising all the way with my 255 STs on the rear and some old 255 MTs on the front (very VERY good ride) I scraped 19mpg. That was following an injector change too 5 mins before I left. They were tested and were good. The truck was running fine before, just had that lazy white smoke on idle. Doesn't seem to have quite so much woof now, but maybe the injectors were just pouring fuel in. I shall have those tested too in due course.

They were original fitment I think. They didn't look like they'd ever been moved, but then my 80 has only done 72k miles. But having sat for 8 years it is possible that the tips actually suffered some corrosion. They look pretty sh*gged.

Chris

 

[warrenpfo]

To bring this back to life.

If i was to fit one of these pumps and have a switched source ie main tank sub tank would it do the job and is this the "cheapest" (read easiest/less hassle) way of plumbing in an Aux tank.

The only problem i see is if the pump fails then you would only have your main tank as the lift pump might struggle to pull form the Aux.

 

[frank rabbets]

The 80 is designed for fairly severe off road angles so why fit another pump. The lift pump is not designed to take pressure coming from the fuel tanks. I can't see a problem lifting diesel from a similar level tank as long as the pipes are big enough. The lift pump is in the main high pressure pump which are ultra reliable and under stressed according to RVS Swindon.

 

[Jon Wildsmith]

It's a low pressure pump and the main reason to fit one as part of a dual tank install is so the fuel system is self priming if you run one tank dry and then switch to the other, saves you having to pull over and prime it manually which could be pretty inconvenient on the motorway

 

[Chris]

"The lift pump is not designed to take pressure coming from the fuel tanks"

Another interesting bit of research Frank. I'd like to read that. Could you post it?

Wouldn't any 'over pressure' would simply go via the spill pipes and back to the tank. On a 20 year old truck, I'd think the pump could do with a little help. Mine certainly benefited from having it fitted when attacking very steep climbs. It stopped it the starvation that's for sure.

Tried the new twin tank set up with the pump not running and there was a noticable stutter when switching over. Now I have the pump running on Ign, it's seamless. Without the engine running it just ticks slowly sending fuel round and round. I took the pipe of the filter to see how much it actually pumped. It's not exactly gushing.

 

[Dave2000]

As per Towpack my 80 has had an issue idling (when it was on the road) that when pointing up hill the idle was slower, pointing downhill the idle raised slightly I had heard about the Walbro pusher was the fix for this but before I went ahead I done some testing.

I first parked the car facing uphill and the idle was down around 100+ rpm, I used the pump on the filter to pressurise the lift pump and it did nothing, zilch, nada. I then put some diesel in a can and put the can on the roof of the car for a gravity feed and fed direct into the pump, again nothing. Further research finds that it is in fact a small spring in the diesel pump governor that weakens or breaks. I have also found that very minor air leaks in the fuel system in particular the diaphragm used to pump fuel (after a filter change for example) can cause all sorts of misfire/poor running the Walbro effectively masks many of these problems.

The Walbro is cited as curing many ills on the 80 but, if your problem is idle/angle related the Walbro 'may' not help.

Here is a link to a thread I started a couple of years ago.

http://forum.ih8mud.com/threads/odd-idle.371858/

regards

Dave

 

[Chris]

But if you fit twin fuel filters (I have) then there is additional resistance placed on the pump that the Walbro then overcomes. Without it on full power, there is a starvation issue. My aim was to build an apoxylips vehicle and the last thing you want is a load of contaminated fuel drained from a wreck clogging up your system when you are being chased.

I have never said fit a Walbro they are brilliant and cure all your issues. I have fitted one because it was my choice to essentially.

Dave I think that some of the air leaks you get are in the primer pump diaphragm itself in the filter. Tiny perforations appear for some reason.

 

[Dave2000]

Your right about the crap you can get in the fuel, modern cars with plastic tanks do not suffer as our older steeds do with their metal tanks. There is a filter in the tank that catches a lot of the rubbish that is always worth a look. I liked the 'apoxylips' quote, I too would like a tough reliable vehicle with the usual hardware but without the 'Mad Max' look. Once my old girl gets back on the road if the running is 'as was' then I will not bother with the pump. You are spot on about the diaphragm drawing in air and yet not showing a fuel leak, it is quite common out here, I think the heat gets to them.

regards

Dave

 

[Gary Stockton]

Just to resurrect this one - I've been toying with fitting a Parker Racor 10micron filter / water separator. The guys want to know fuel flow rate. Did you ever test yours Chris, coz if not I'll just quote the Walbro rating of 225 litres/hour and see how we go.

Cheers

 

[frank rabbets]

Never said it was research Chris. JMO. The lift pump intake relies on atmospheric pressure, about 14/15 psi it does not take much research to know it must have been designed with this in mind. Or was I jumping to conclusions? What pressure does the Walbro pump produce?

 

[Dave2000]

Hmmmm.....about my Optima battery thread

regards

Dave

 

[Chris]

Gary, I'd have to look out the specs, but it was something like 105 LPH and between 7 and 11 psi I think. It's a low pressure low volume helper pump. It's not a fuel transfer pump. It cured the stalling problem on the off roader straight away. When tipped skywards it was struggling to pull fuel up that height. It doesn't push the fuel around the IP, it just gets it to the filter basically. If you pull the hose off and run fuel into a can, it's not exactly a jet!

 

[frank rabbets]

11 psi = about 30 ft head of diesel whether pumped with a pressure pump from the tank or lifting with a lift pump. The latter assumes an atmospheric pressure of 11 psi for simplicity.

REF :- Torricelli 1608-1647. That's his lifespan not ZIP code.

 

[Gary Stockton]

Thanks folks

 

[frank rabbets]

I recently spoke to RVS Swindon. They think home brewed fuel can shorten the life the diaphragms and seals in the pump. Touch wood mine is OK at nearly 20 years old and 145,000 on the clock. Pump fuel only.

 

[Bat21]

I'm currently in Morocco and are having problems on the long steep hill climbs, the motor struggles to get above 2,000 rpm and almost stops completely if the climbs are long enough.
I have found the solution is to not let the tank drop below half, I'm guessing this limits the amount of 'lift' the tank pump needs to lift the fuel?
Looks like this will be on my list of mods to do when I get home.

 

[MarkW]

Making me jealous Paul, hope your having a good trip

 

[chapel gate]

I'm currently in Morocco and are having problems on the long steep hill climbs, the motor struggles to get above 2,000 rpm and almost stops completely if the climbs are long enough.
I have found the solution is to not let the tank drop below half, I'm guessing this limits the amount of 'lift' the tank pump needs to lift the fuel?
Looks like this will be on my list of mods to do when I get home.

Take the fuel hose off the top of the fuel filter closest to the bulk head. Blow down it as hard as you can a few times, you will hear the fuel in the tank bubbling. See if that improves things.