Fuel pump issue - HZJ 73, 1HZ

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Joined
Jun 19, 2023
Threads
4
Messages
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Location
Misawa, Japan
I’m having issues with the fuel pump slowly leaking. I took it to a local mechanic when this started in Dec. he replaced the o rings and we crossed our fingers that it would work. I couple weeks after I brought it home, it’s leaking again. Not massive leak, just drips. Is this a known issue? Do I probably need a new fuel pump? Just looking for some context. Thanks. Pictures are the best I can get. I don’t have a garage or way to lift the truck.

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There are numerous O-rings on a fuel injection pump. It seems that the leaking O-ring was not replaced, or another one has recently failed. To do a proper job, the pump should be removed from the engine and rebuilt with new O-rings and gaskets by a diesel specialist.

O-rings always leak with age and it does not indicate that there is anything mechanically wrong with the pump.

You need a new rubber travel stop for your front axle. Probably a pair.
 
I’m having issues with the fuel pump slowly leaking. I took it to a local mechanic when this started in Dec. he replaced the o rings and we crossed our fingers that it would work. I couple weeks after I brought it home, it’s leaking again. Not massive leak, just drips. Is this a known issue? Do I probably need a new fuel pump? Just looking for some context. Thanks. Pictures are the best I can get. I don’t have a garage or way to lift the truck.

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If it starts and runs/drives fine then you do not need a new pump. It is mechanically working fine. But is the mechanic you took it to a diesel specialist? Do they do pump and injector rebuilds?

If it were my truck, I would clean off all the wet areas, start it up, then watch to see where the leak is coming from. Then focus on that spot. It could be all you need to do is tighten the supply line, the return line or, (less likely) an injector line.

Worst case scenario, you may need to get the pump rebuilt by a diesel specialist shop as @Eurasiaoverland has suggested. All the best getting this sorted! :cheers:
 
There are numerous O-rings on a fuel injection pump. It seems that the leaking O-ring was not replaced, or another one has recently failed. To do a proper job, the pump should be removed from the engine and rebuilt with new O-rings and gaskets by a diesel specialist.

O-rings always leak with age and it does not indicate that there is anything mechanically wrong with the pump.

You need a new rubber travel stop for your front axle. Probably a pair.
Thank you for the reply. My shop replaced a couple o rings and now it is leaking at a lever. I am having trouble finding a mechanic who will take this on in LA. My shop who have helped me with a few things like brakes and axle things don't really have any experience with this pump because the 1HZ is a rare engine in the US. I don't blame them. I'm scratching my head about how to proceed.

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If it starts and runs/drives fine then you do not need a new pump. It is mechanically working fine. But is the mechanic you took it to a diesel specialist? Do they do pump and injector rebuilds?

If it were my truck, I would clean off all the wet areas, start it up, then watch to see where the leak is coming from. Then focus on that spot. It could be all you need to do is tighten the supply line, the return line or, (less likely) an injector line.

Worst case scenario, you may need to get the pump rebuilt by a diesel specialist shop as @Eurasiaoverland has suggested. All the best getting this sorted! :cheers:
Thank you - I appreciate the help. I have passed your thoughts along to my mechanic who has the truck now. (I live in an apartment and don't have any way to work on the truck in my own space). Again - thanks for sharing your thoughts on this.
 
This generation of diesel injection pumps were all basically the same - Bosch, Zexel, Denso which were fitted across many platforms. Try a diesel specialist. Even if they are used to Cummins etc engines, they should be able to work on it.
 
Good information. I think there is a Diesel shop in the PNW that rebuilds alot of the Toyota pumps, I don’t recall their name, but guessing someone else can post up contact information.

Also, is there anything that needs to be set/reset after the pump is removed and reinstalled?
 
The pump should be plug and play when it comes back. The pump timing may need some fine adjustment. Mine ran perfect after a rebuild so I left it as it is.
 
The pump should be plug and play when it comes back. The pump timing may need some fine adjustment. Mine ran perfect after a rebuild so I left it as it is.
Thanks!
 
Good information. I think there is a Diesel shop in the PNW that rebuilds alot of the Toyota pumps, I don’t recall their name, but guessing someone else can post up contact information.

Also, is there anything that needs to be set/reset after the pump is removed
Diesel Fuel Pump Repair Oregon – Diesel Fuel Injection Services - Scappoose, OR - https://dfispdx.com/diesel-fuel-pump-repair-oregon/

If needed DFIS in Portland have rebuilt a ton including mine last year.
 
When you refit the pump, you need to return the static timing to the correct position. There is a factory scribed mark along the edge of the left hand mounting flange which should align with a mark on the rear timing cover. If the pump has only been resealed, matching this mark should be fine. But if internal components of the pump have been replaced, it should technically be timed using a dial indicator.
 

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