Author Topic: Losing Prime again and again....MTDI AHU  (Read 2604 times)

November 10, 2009, 10:43:24 am

avocado

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Losing Prime again and again....MTDI AHU
« on: November 10, 2009, 10:43:24 am »
Hi

I put a AHU in a Suzuki Sidekick.  Bought amanual pump from a fellow on here and the little truck runs great!  Well...most of the time.

It seems to lose prime at really weird times. 

I recently put a clear fuel line (  5/16") between the fuel filter and the pump in order to see what the hell is going on.  I have found that sometimes after sitting the fuel line is completely empty of fuel.  I cannot figure out where the air is coming from...all lines are tight and new. 

I was wondering if the fuel is just pulling out of the line (air coming from the IP side after shutdown?) and going back into the tank. 

Should I put a check valve in the line at the tank to make sure fuel is only going to the engine and not back into the tank? 




Reply #1November 10, 2009, 06:46:04 pm

gldgti

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Re: Losing Prime again and again....MTDI AHU
« Reply #1 on: November 10, 2009, 06:46:04 pm »
check the injector return lines, and other return lines. when swtiched off, it will allow air in and all the fuel will drain backwards.
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Reply #2November 11, 2009, 01:20:14 pm

avocado

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Re: Losing Prime again and again....MTDI AHU
« Reply #2 on: November 11, 2009, 01:20:14 pm »
Wouldn't it be easier to just add a check valve? 

The thing is that I remember having put my return line into the tank at a pretty high level, so it may be sucking air from back in the tank...

Reply #3December 02, 2009, 11:17:24 pm

D.Loops

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Losing Prime again and again MTDI AHU
« Reply #3 on: December 02, 2009, 11:17:24 pm »
air in the fuel would be a problem for starting must be sucking air from somewhere or fuel could be leaking back to tank could try a non return valve?

Reply #4December 03, 2009, 01:57:22 am

westyventures

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Re: Losing Prime again and again....MTDI AHU
« Reply #4 on: December 03, 2009, 01:57:22 am »
Check the pump shaft seal.
Karl Mullendore
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