BJ73 3b 3.4 fuel feed problems

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DutchBJ73

DutchBJ73

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Good afternoon fellow offroaders,

I am new to the forum, and i was looking for a thread with this similar issue i am experiencing on my BJ73, unfortunately i did'nt find any. I changed the headgasket (OEM) because of a leak between the cooling system and one of the cilinders. brought the head to the shop for a crack-check, rebuild, and re-used the head.

Everything seems to operate the way it should, except for the fuel consumption. I keep getting air into the system, even though i changed all the gaskets and washers. When i bleed the air and start the car, it runs fine for about 10 minutes stationary. After 10 minutes it starts stalling and the engine shuts off. I can't find any leaks around the hoses.

has anyone experienced this issue, or maybe knows a way to fix this (or check for other problems)? I would really apreciate any info about this problem. Thanks in advance :) !!

(here is a pic of my fuel pump)

IMG 20210812 143204
 
Rigster

Rigster

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May 6, 2010
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256
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Vernon, BC, Canada
This is going back a loooong time for me, but if you have a FSM, look at the fuel pump - there should be a diaphragm at the end of the pump. I would check that for starters, if it has a tear in it, that can cause issues like this. I had to replace one of those on one of my 3B's a while ago.
 
lacalvette

lacalvette

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Oct 15, 2010
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Quebec, Canada
Fuel line are under vacuum from tank to feed pump (where is the hand priming pump).
Feed pump build up fuel pressure so the main fuel injection pump doesn't Cavited.

Hense any leak after the feed pump will shows fuel. Any leak before will let air in...
So flex hose connection, tank pipe, hand priming Pump, a primary fuel filter(water separator)... may start there?
Just an idea.
 
DutchBJ73

DutchBJ73

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Hey @Rigster and @lacalvette thanks for the quick reactions! I will definitely check those hoses and connections. I just found out i didn't watch close enough at the hand priming pump. Because there was a very bad hose connected (fuel return) to the banjo bolt.
IMG 20210812 164906
if this hose isn't the only issue i will let you know. :D
 
Rigster

Rigster

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Yup, that could very well do it! I should also mention that the more I think about it... the bad diaphragm allows fuel back into the tank, so hard to start... but once running seems fine, but there can also be a higher RPM idle rate. Once the tear gets bigger, the idle tends to get higher and higher....

So, if you are not also seeing those problems, then it probably isn't the diaphragm. Like I said, it was a looong time ago and it takes a little longer to pull those files up and blow the dust off of them.... lol
 
Felde

Felde

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Sep 11, 2020
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Leverkusen , Germany
Yup, that could very well do it! I should also mention that the more I think about it... the bad diaphragm allows fuel back into the tank, so hard to start... but once running seems fine, but there can also be a higher RPM idle rate. Once the tear gets bigger, the idle tends to get higher and higher....

So, if you are not also seeing those problems, then it probably isn't the diaphragm. Like I said, it was a looong time ago and it takes a little longer to pull those files up and blow the dust off of them.... lol
Thanks anyway. I was always wondering what the symptoms of a teared diaphragm would be. Now I know :clap:

Good luck DutchBJ73. See you on the Buschtaxitreffen at September 10th?
 
DutchBJ73

DutchBJ73

Joined
Aug 9, 2021
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Netherlands
Good morning guys,

The bad hose/connection seemed to be the problem.
It starts and keeps running fine now.

@Rigster
I will check the diaphragm soon, because the first startup takes a while now.

@Felde thanks for the invite, i didn't know about the buschtaxitreffen yet. I googled it and it looks awesome! Unfortunately my cruiser won't be finished that soon, so maybe next year.
 

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