Another Walbro Thread - Successful Cure of a Stumbling 1HDFT (1 Viewer)

[gifu]

Just a quick post here regarding the Walbro pump as a pusher pump. This has been discussed a few times, and there are arguments for and against such a pump.

Anyway, my 1HDFT (swapped into an FZJ80) started experiencing serious stumbling at 2500RPM or so. After reading up a bit, this is a common issue on the rotary pumps that are starting to… ahem… die.

Anyway, being the cheap bastard I am, rather then rebuild the IP, I put a Walbro FRB-5 (formerly the 6065 model) pusher pump. More information on that pump here:

https://forum.ih8mud.com/diesel-tech-24-volts-systems/32275-pusher-fuel-pump-walbro.html

I purchased the pump here: Auto Performance Engineering - Walbro fuel pumps and more

Anyway, to install the pump, I first unbolted the main fuel line from the top of the tank (it’s about 1’ long, and it is bolted with a banjo bolt to the tank, and a flare fitting to the beginning of the metal fuel line on the frame). I cut the fuel line right after the banjo bolt, flared the metal part of the line, and slipped some 5/16” fuel hose over it. This runs to the fuel pump bolted to the frame (passengerside). From there, I ran more 5/16” fuel hose to the original metal fuel line, and forced it over the existing flare, affixed with more hose clamps. The pump is wired to switched (ignition) 12V.

The difference is night and day. I swear, it even sounds better at idle. A little smoother and less clatter.

I didn't take picts during install, but here is the fuel line that I cut and flared to be able to splice in the pump.

 

[Tapage]

I'm temted to add one .. maybe in the engine bay just before my check valve ..

 

[Greg_B]

Interesting. Thanks for posting the changes, and your thoughts.

When I visited an injection shop and talked low pressure pusher pump, and the Bosch rotary VE pump, I got the impression running one would be bad for their business. I interpolated this meant it would keep the injection pump alive longer...even if no issues are apparent.

Tapage...I've always understood its best as a pusher, not a sucker.

 

[canucksafari]

Same here. The Aussies on OL or Patrol4x4 always put them close to the tank as pusher pumps.

 

[roscoFJ73]

Interesting. Thanks for posting the changes, and your thoughts.

When I visited an injection shop and talked low pressure pusher pump, and the Bosch rotary VE pump, I got the impression running one would be bad for their business. I interpolated this meant it would keep the injection pump alive longer...even if no issues are apparent.

.

Keeping a dying pump alive is what its doing. You cant feed more fuel into a pump that is already full and this is probably why it works sometimes and not others
I think a worn feed pump is likely for those who report that pumping the primer pump increases rpm at idle.

I guess it would be bad for business for an injection shop to recommend pusher pumps instead of rebuilds.
But when the feed pump is worn out,a visit to the injector shop is not far away anyway

 

[Greg_B]

Keeping a dying pump alive is what its doing.

Yes, likely.

I guess it would be bad for business for an injection shop to recommend pusher pumps instead of rebuilds. But when the feed pump is worn out,a visit to the injector shop is not far away anyway

I was not clear. On a new, or good condition pump, it was suggested that a low pressure pump would keep the injection pump out of the rebuild shop longer. The pump on my 1HD-T swap engine will be getting baselined before the engine goes into the FZJ. It will also be getting a Walbro near the tank.

 

[Tapage]

Tapage...I've always understood its best as a pusher, not a sucker.

appart of this advice .. IIRC a pusher must be inside the tank .. and everything out will be a puller ?

 

[Greg_B]

Details, Tapage...details

Yes, to be technical. I would still suggest closer to the fuel tank then the front...as is reasonable.

 

[canucksafari]

Yes, to be technical. I would still suggest closer to the fuel tank then the front...as is reasonable.

Closer to the tank also means bleeding the fuel system is much easier. No need to use the primer pump.

 

[Tapage]

I have a sucker .. ( thought ) close to my IP in Tencha .. it make the bleeding procesure as easy as ON in a cabin switch ..

 

[finderscuba]

I have a sucker .. ( thought ) close to my IP in Tencha .. it make the bleeding procesure as easy as ON in a cabin switch ..

I'll second that. I installed my Walbro right before the filter cap. After a filter change, turn on the key and it's primed.

Because the 1HDT has an overflow, the pump will run with a very low duty cycle even when the engine is not running.

To me, the main difference between mounting in/at the tank and at the IP is that pulling from the IP could suck air if there are any leaks whatsoever. Pushing from the tank may just weep fuel through those same leaks. In my case, I've replaced all the fuel lines and clamps and can find no leaks.

Performance wise, I have noticed no difference with the Walbro running or with the fuse pulled. But my intention with the Walbro was to improve fuel flow in winter (-25°C and colder).

 

[mudstorm]

Im impressed

when my 80 goes on a slope like a dune or rock with the nose to far in the air it dies

im guessing my transfer pump is PooPed . and long story short i believe the pump was played with
before i brought it so she has come off and sent to A1 diesel injection today

ill let you know what it set me back $$ and keep you updated on improvements

even so for the easy priming you got me sold on a little electric pump

 

[roscoFJ73]

Im impressed

when my 80 goes on a slope like a dune or rock with the nose to far in the air it dies

I take it yours is a factory turbo. I have heard of 4-5 X 1HD T doing this but never a 1HZ.

Where the hell is Peth?

 

[70sguy]

Weak feed pump in the IP is probably part of the problem.
Pulling fuel up from the tank through the smaller dia 1FZ Gasser fuel lines and tank pick up with all the restrictive banjos and and high pressure fittings doesn't help either. Walbro is helping make up for the difference I would imagine.
Stock 1HD-FT fuel supply line is 12MM (1/2")

I have run a stock 1FZ pick up and line set up with a 1HD-T, I hogged out every fitting and restriction as wide as it could go and also ran a Walbro 6065 from the get go. I later changed out the pick up to a
proper HDJ81 unit.

Good work on the 80.

 

[mudgudgeon]

Im impressed

when my 80 goes on a slope like a dune or rock with the nose to far in the air it dies

im guessing my transfer pump is PooPed . and long story short i believe the pump was played with
before i brought it so she has come off and sent to A1 diesel injection today

ill let you know what it set me back $$ and keep you updated on improvements

even so for the easy priming you got me sold on a little electric pump

this is fairly common, mine does it also. I have heard of injector pumps being fully rebuilt to try and fix this, with no improvement. One theory was that the govenor weights move with the nose uphill causing idle to drop tool low
I have intended to fit a pusher pump at the tank and a surge tank after the filter to fix this, it drives me mad offroad.