HDJ81 bleed fuel system

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Apr 10, 2019
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Location
Gilroy, California
Hello fellow mudders. I own an imported 1990 Toyota Land Cruiser equipped with the HDJ81 4.2L inline 6 diesel engine. About a month ago the truck wouldn't start, after pumping the fuel primer on the fuel filter to build pressure then the truck fired right up. After a few seconds later I noticed fuel was leaking from the diesel injection pump. Pulled the injection pump off to get it rebuilt and reinstalled it.

After reinstalling everything, I have the fuel lines disconnected from the injectors and while cranking many times, I am not getting fuel out of the lines. I even have the fuel return hose capped off in hopes to help build the fuel pressure but still no fuel out of the lines. Tried looking up fuel bleed procedures for this particularly engine and didn't see anyone post anything.

The shop that rebuilt the pump mentioned that the pump was not outputting fuel pressure to specs after the rebuild. They asked if I had issues with starting which I never did so I decided to take the pump as is and give it a try. They said that if it didn't work then I would need to bring it back for a distributor replacement. I feel that even if it didn't build enough fuel pressure to specs that it should at least build some pressure to drip out of the fuel line at the injector but it doesn't.

Any suggestions or recommendations on what to check or how to prime the fuel system would be greatly appreciated. I want to rule anything out that I might have missed before pulling the injection pump back off to get the distributor replaced on it. Thanks in advance.
 

mudgudgeon

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Across the pond, and upside down
The shop that rebuilt the pump mentioned that the pump was not outputting fuel pressure to specs after the rebuild. They asked if I had issues with starting which I never did so I decided to take the pump as is and give it a try. They said that if it didn't work then I would need to bring it back for a distributor replacement. I feel that even if it didn't build enough fuel pressure to specs that it should at least build some pressure to drip out of the fuel line at the injector but it doesn't.

For starters, WTF!

How much did you pay for a rebuild, only to get it back not working to spec?


There is no real trick to bleeding these, unless there an issue with something. It can take a little patience though.

- Use the hand primer at the fuel filter to prime the pump.
- Remove glow plugs from the head so you can crank the engine over with no compression.
- Use the starter to turn it over until fuel comes out the injector lines. (This may take a minute or two or more, and you may have to reprime with the hand pump)
- Once you have fuel at each of the 6 injector lines, reattach lines, reinstall glow plugs and try to fire it up. It may run rough for a minute or two until all air is out of the pump and lines.

The hand pump primer on the fuel filter assembly are prone to failure and can leak fuel, or allow air to be sucked into the fuel pump. If air is getting drawn in to the pump, you won't get full pressure at the injectors. But I would expect to see some fuel if the injector lines aren't connected.

If you're getting nowhere, try using a 4-5litre bottle of fuel connected to gravity feed directly to the pump and bypass the filter system to see if you can get it to prime.

Also, I would think its better to leave to spill/return line connected, not plugged.
 
Joined
Apr 10, 2019
Messages
2
Location
Gilroy, California
@mudgudgeon thanks for the reply. Let me try removing the glow plugs to help with turning the engine over and see if this will prime it. After attempting to pump the hand pump primer on the fuel filter, I did notice some fuel was starting to leak from the top so I will have to get this replace once I get the truck fired up.
 

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