Installing a Walbro pusher pump - update

[Bat21]

Making me jealous Paul, hope your having a good trip

A great trip so far Mark..... as beautiful as ever.

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.

I had thought of that as my next plan of action if the problem escalates.

 

[Chris]

Don't use an airline or you'll blow the filter off the end

 

[Dave2000]

If the engine driven lift pump cannot draw fuel at a steep angle then it is on the way out, or you have a blockage, or pinhole in the fuel line, primer diaphragm.

Fitting a pusher may well work but is just hiding the problem, hope all goes well.

@Chris I agree about the airline but if the tank filter is blocked, he is better off without it, just carry a spare under bonnet filter, sort when back home.

Regards

Dave

 

[Firewout]

I had the same issue as Bat21.
replacing the thermowax element at the ip by a blanking plate cured it.
easy fix. I guess you'll easily find a blanking plate in a Moroccon workshop. they seem to be pretty standard.
I connected the 2 coolant lines from the thermowax element with a small tube.

 

[Bat21]

Thanks for the advice here guys. Just about to start heading North today from our current location so will let you know how it goes.

 

[Bat21]

I had the same issue as Bat21.
replacing the thermowax element at the ip by a blanking plate cured it.
easy fix. I guess you'll easily find a blanking plate in a Moroccon workshop. they seem to be pretty standard.
I connected the 2 coolant lines from the thermowax element with a small tube.

That's worth knowing, thanks.
What does the thermowax element normally do? Are there any downsides to removing and blanking it off?

 

[MarkW]

Ali Nassir in Zagora or Attraxion 4x4 in Marrakech if you need any help. But you probably knew that anyway Paul.

Got a good contacts inEssaouura and Boudnib as well if desperate

 

[Firewout]

the thermowax changes the injection timing when the engine is cold. when it's removed, the engine smokes a little bit more the first few minutes when starting from cold. I removed it and startup at -10 is no problem : the usual half crank of the starter motor.

 

[Dave2000]

Unsure how removing the cold start can affect the lift pump? I did remove my ACSD about 6 years back, engine starts perfect hot or cold, not been to Siberia with it yet though.

Regards

Dave

 

[frank rabbets]

"Automatic Cold Start Device". That means it's only operative when the engine is cold. It advances the pump timing by a very small amount when the engine is cold and is inactive when the engine is hot unless it is seized in the cold position. I would not think there is much difference in engine performance running cold without it. Certainly no damage. Benefits of removing it are ;_

1. No possible diesel leaks.
2. No possible water leaks due to aluminium corrosion.
3. No long term running in the cold timing point.
4. No possibility of the little lever breaking off and ruining the pump.

Dave could there be a 5th advantage. Drawing air through a weak 0 ring through the action of the lift pump and causing fuel starvation? I don't know if there is negative or positive pressure in there.

 

[Towpack]

The thermo wax element is for the ACSD mechanism. It advances the pump timing and raises the idle speed on cold starts, a bit like an automatic choke that some older vehicles with carbs used to have. Removing it will just make the engine idle speed lower on a cold start. I removed mine due to a fuel leak past the the shaft seal so I just use the hand throttle to raise the idle speed slightly on cold starts. Other than a lower idle speed it made no difference whatsoever to starting.

 

[frank rabbets]

ACSD was probably fitted for pollution requirements. Older style diesel engines started and ran without one.

 

[Firewout]

Air entered the ip due to a bad o-ring at the thermowax element, causing the engine to stall when the truck was idling nose up.

 

[Dave2000]

Unsure Frank, much of the pump internals rely on diesel as a lubricant, there may be some leak off running through there?

There was an article I read many years ago, it was about certain diesels (not necessarily 80's ), having pump damage from having the thrust faces of the lift pump internals damaged by additional pressure from an external pump. Yet to see any physical evidence of this though. Without doubt it is an advantage to get rid of the primer head, and as per Chris perhaps have additional filters. I think the three OE ones already fitted are sufficient for my use, I do miss the little glass or plastic 'sight bowls' of yesteryear though.

Regards

Dave

 

[chapel gate]

Unsure Frank, much of the pump internals rely on diesel as a lubricant, there may be some leak off running through there?

There was an article I read many years ago, it was about certain diesels (not necessarily 80's ), having pump damage from having the thrust faces of the lift pump internals damaged by additional pressure from an external pump. Yet to see any physical evidence of this though. Without doubt it is an advantage to get rid of the primer head, and as per Chris perhaps have additional filters. I think the three OE ones already fitted are sufficient for my use, I do miss the little glass or plastic 'sight bowls' of yesteryear though.

Regards

Dave

I remember them. Mounted on the bulk head and made a poping noise once the fuel was heated?

 

[Bat21]

Just a quick update on this one.
Currently in Chefchaouen so only 75 miles back to the UK mainland.
There is certainly a power loss it the tank is allowed to drop below half a tank, keeping the tank topped up every 200 miles max is keeping the truck running fine.
I suspect the tank pump is fubbared and the main IP is having to 'lift' the fuel from the tank and is struggling when the level drops.

 

[chapel gate]

There is no tank pump on the diesel. Just a pick up pipe with a filter sock on the end.

 

[Chris]

The pump on the engine is both the lift pump and the injector pump. This is why I fitted a pusher pump. Nothing to do with injection, it was to help prevent fuel starvation to the IP on steep inclines and blockages etc. With having two fuel tanks, you need to change over at some point. There can be an interruption in fuel supply at this point meaning at speed, the IP is short of fuel. The pusher pump means that this is pretty much unnoticeable. It was never fitted to improve performance or any other notion of fuel injection. I don't actually know what would happen if the lift pump failed completely. Would the pusher pump keep me going?

 

[Dave2000]

I have a sneaky feeling either the tank filter is full of brown sludge or the pick up tube has a hole.

Regards

Dave

 

[Firewout]

I don't actually know what would happen if the lift pump failed completely. Would the pusher pump keep me going?

Chris, when you look at the schematic of the ip, the pressure to the metering valve is controlled by a differential pressure regulator bypassing the transfer pump and the housing pressure regulator. So if the pressure of the pusher pump is high enough, imho this would work.