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Anyone know the injector opening pressure for a 4JB1-T?

Getting the best performance from your Isuzu, the in's and out's

Anyone know the injector opening pressure for a 4JB1-T?

Postby Waco1 » Wed Jan 24, 2024 10:12 am

Sending my diesel injectors into the shop and the tech can't find the opening pressure #/data/PSI to test against.

Thanks -

Bill
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Re: Anyone know the injector opening pressure for a 4JB1-T?

Postby geeves » Wed Jan 24, 2024 10:31 am

1891 psi
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Anyone know the injector opening pressure for a 4JB1-T?

Postby Roadrunner » Wed Jan 24, 2024 4:13 pm

The figures I found were 2650 psi for the 4jb1, and 2133 psi for the 4jg2 idi engine, the 4jg2 figure comes from the owners handbook, but I don't remember where I got the 4jb1 figure from. Personally, I'd ring another injection shop to see if they have the correct pressures.
Edit: I found another source of information, here's a link- https://manuals-free.com/uploads/files/ ... r_4jb1.pdf

This is for the 5 hole nozzles, 1st stage injector opening pressure 19.5 mpa (2683 psi), 2nd stage 26.5 mpa (3843 psi). I don't know if your engine has the same specs.
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Re: Anyone know the injector opening pressure for a 4JB1-T?

Postby paulthepilot5 » Fri Jan 26, 2024 10:10 pm

Depends on the injectors you have, there are multiple types with different specs
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