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Hi all. Mechanical question this time…

 

I’ve noticed the engine oil level is increasing, smells of fuel and seems thin, signs that diesel is getting in somehow. Going to send a sample for analysis though anyway. 
 

It’s an Isuzu 3KC1 with a mechanical lift pump, mounted next to the injection pump. What’s the chances of the lift pump leaking vs injection? And before I pull it apart, anyone know if the lift pump is rebuildable using off the shelf generic o rings/oil seals etc? I can’t find a rebuild kit anywhere… Oh, and all fuel lines are external so I’m guessing it’s got to be one of the pumps. 

I’ve attached the pages from the workshop manual about fuel delivery, and it doesn’t mention a lift pump at all, only injection! 
 

Thanks!

E670926E-E02D-41D5-BF0D-5EBE096BFAB6.jpeg

Edited by cheesegas
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I do not know the engine, but from what you say I would start by removing the lift pump and examining the diaphragm, if you can get to it.

 

In this day the complete pump may be the only spare available, but in any case the diaphragm is likely to be a special to the pump item.

N

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You can get an idea about the diaphragm but putting your thumb over the inlet port and spinning on the starter for a few turns. After 30 seconds the vacuum in the pump should still be significant. Then repeat on the outlet but this time you are assessing how well it holds pressure.

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Thanks both. 
 

Unfortunately I can’t find even the complete lift pump anywhere, not even a part number. It’s a 30 year old engine but starts and runs perfectly. Hoping it’s a shaft seal rather than the diaphragm - if it is, I may have to remove the lift pump, blank off the hole and install an electric one. 
 

I’ll do the vacuum test on the pump too, thanks!
 

 

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11 minutes ago, cheesegas said:

Thanks both. 
 

Unfortunately I can’t find even the complete lift pump anywhere, not even a part number. It’s a 30 year old engine but starts and runs perfectly. Hoping it’s a shaft seal rather than the diaphragm - if it is, I may have to remove the lift pump, blank off the hole and install an electric one. 
 

I’ll do the vacuum test on the pump too, thanks!
 

 

 

FWIW some Isuzus have an electric pump as standard so that would seem to be the easiest way to solve it.

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