1HD-T - Possible air leak from fuel primer ? (1 Viewer)

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Ever since I replaced the primer pump, I haven't had any problems. However, I think there is something wrong with the fuel cap. I have taken it apart and cleaned it all up. Butt there is still significant vacuum in the table whenever I remove the cap to fuel up. I'm thinking I might buy a new one. Anyone have a part number/source for them?
 
Found one, and thought I would go ahead and post the part number here in case anyone else is looking for one.

77310-12150

Fuel cap.jpg
 
Been trying to find Tygon clear fuel line in 10mm and 12mm here in Canada no luck. Anyone have leads? Trying to replace tank to fuel filter and fuel filter to Injection Pump. Chasing an issue with my 1995 1HD-FT. Thanks
 
one of the other symptoms, if you keep rpm on 1700-2000, you may hear that engine is not working straight. My problem with 1hd-ft is that the sound of the engine is not good when it is stationary between 1700-2000rpm. The feeling that the fuel is not fully flowing into the engine even when the vehicle first takes off. also excessive movement of the instrument cluster at the max rpm.

Although there is no air in the transparent hose after prime, please check return line. The strange thing is that the pump can also take in air and send it to the return line. From there to the tank. The return line going inside the tank is very close to the suction pipe. the distance between them is 2-3 cm.

If you put fuel in a separate jerrycan and put the prime suction hose into the jerrycan, you can see that the pump sound is okay. no vibration on the engine.

Time to find leakage on the pump or injection return line or pipes, or pump revision
or
need to temporary try to extend return line pipe with a hose to increase distance to the suction to prove.

I should also mention that the air from the return line goes to the fuel tank. After a while, all the fuel in the fuel tank is mixed completely with the tiny air bubble.

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Can someone confirm fuel line sizing for a 1HD-FT. Looking for clear Tygon fuel line form tank to fuel fileter, filter to IP, IP return line to tank.

If I get 1/2" ID and 3/8" ID that should cover me right?

 
The size is 12mm, but 1/2 " will do. If you are spending a bit of money, buy a sample and test it. Get rid of any finger clamps still on the fuel lines and replace them with the other type that you tighten with a screwdriver or socket
 
The size is 12mm, but 1/2 " will do. If you are spending a bit of money, buy a sample and test it. Get rid of any finger clamps still on the fuel lines and replace them with the other type that you tighten with a screwdriver or socket
Thanks...I ended up juggling and reseating the hoses and it seemed to have fixed the issue. Going to change the lines to Tygon and ended up ordering some fuel injection style hose clamps

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My 1hdft has surging on full kickdown around 3k rpm. It drops to 2.7 and back up if I keep my foot in it. Swings wildly. Air in fuel system?
 
Air in fuel system?
Its quite likely. Air and damned air is always the first culprit to be blamed. But the higher rpms make that less likely as the amount of fuel the feed pump pulls through increases with rpms and usually overcomes air bubbles. Its does happen though.
Will it break down revving it in neutral? Even if it doesn't, you could still rig up a piece of clear hose to see if any bubbles are present at higher rpms.
It could be a simple fuel starvation issue, maybe some sludge in the tank partially blocking the fuel pick up.
I'm assuming you have a new filter on it.
 
Its quite likely. Air and damned air is always the first culprit to be blamed. But the higher rpms make that less likely as the amount of fuel the feed pump pulls through increases with rpms and usually overcomes air bubbles. Its does happen though.
Will it break down revving it in neutral? Even if it doesn't, you could still rig up a piece of clear hose to see if any bubbles are present at higher rpms.
It could be a simple fuel starvation issue, maybe some sludge in the tank partially blocking the fuel pick up.
I'm assuming you have a new filter on it.
Thx. It revs normal until I kick down. I dont have a new filter. But I'll try that and look for vacuum leaks.
 
The difference between revving an engine in neutral and revving it when under load has a vast difference in the amount of fuel called for.

There are a couple of filters, there is one on the fuel pick up in the tank and the one you service under the bonnet. Also check the pipework that runs from the injectors back the fuel pump/tank.

Of note, the pump on top of the filter has a rubber diaphragm, this cracks with age and allows air in, depending on your location you may need the version with the fuel heater fitted.

Regards

Dave
 
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The difference between revving an engine in neutral and revving it when under load has a vast difference in the amount of fuel called for.

There are a couple of filters, there is one on the fule pick up in the tank and the one you service under the bonnet. Also check the pipework that runs from the injectors back the fuel pump/tank.

Of note, the pump on top of the filter has a rubber diaphragm, this cracks with age and allows air in, depending on your location you may need the version with the fuel heater fitted.

Regards

Dave
Thx Dave. I ordered the fuel heater assembly but the actual heater is discontinued.
 
Thx Dave. I ordered the fuel heater assembly but the actual heater is discontinued.

I replaced mine with a primer without the heater. I'd had a leak on the heater and fixed it with an o-ring, but didn't want another failure so I removed it.
 
Vacuum? On a diesel?

Lol
Technically he is correct, the pump sucks fuel and if there is a blockage and fuel cannot be sucked up, the pump will be creating a vacuum.

Regards

Dave
 
Just realized I can't install this without the heater. Unless there's a blank I can put in place.

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