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Discussion Starter · #1 ·
Hey guys so I’ve been having a air leak in my fuel for about two weeks now and so far I have replaced primer pump and filter along with new injectors and 12mm pump and still had the problem so I replaced fuel pickup in the tank and ran a new line from the tank to the filter and still had the problem so I replaced the hose from the filter to the fuel pump and still having the same issue… any help would be much appreciated cheers.
 

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Discussion Starter · #3 ·
Have you tried pressurising the tank?

fitted a lift pump behind the filter and it fixed the issue and couldn’t see any weeping etc but was pressurising the fuel pump too much and started to pushed fuel into the crank case so that caused me to have oil dilute so I took it out and replaced oil and I’m back to square one
 

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SUI GENERIS UTE
GQ Ute 1990 Silvertop
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You have changed the usual suspects so it may require some more investigation.

Usually a lift pump like a carter P4601 is fitted with a 12mm IP to keep a good supply of fuel and pressure at the IP. Because the lines will be under pressure to the IP and not under vacuum from the IP will usually not allow air in the lines. If you have a leak you will see fuel leaking at the problem area, but not always. I am somewhat confused by your statement you fitted a lift pump and have fuel in the crankcase. There is no connection to the crankcase with a VE pump. The only way to get fuel dilution in your oil is if the injectors are leaking when stopped or you have massive fuel being injected but your engine would be running very badly with massive EGT and smoke. Or your IP is somehow beyond logic is still pumping fuel when stopped or your 12mm element in the IP is somehow worn beyond i can imagine. Or you fitted a very high pressure lift pump like 40+ psi. Or your rings are very worn and you have very low compression, which is most likely.

Another way to check where air is leaking in the fuel without a lift pump is to fit some clear hose at specific points like between filter and IP, before filter and tank to main delivery line or steel lines. You suggested you have run a new line from tank to filter eliminating the steel line. Just be aware the std fuel line is a good quality hose but i have found it can have a crack allowing air in but under pressure it wont leak until its well over 15 psi pressure in the hose.
 

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Y2KGUII ZD Wgn
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fitted a lift pump behind the filter and it fixed the issue and couldn’t see any weeping etc but was pressurising the fuel pump too much and started to pushed fuel into the crank case so that caused me to have oil dilute so I took it out and replaced oil and I’m back to square one
Just to add to what Peter said, I have had a Carter 4601 lift pump in mine for many years, the pump is capable of 16psi through 13mm + hose, our hose is 10mm so wall friction limits pressure to 13psi max on mine, it runs at 10.2psi on normal cruising @ 100k. OK so I have a VP44 it really is only a electronic version of what you have so your pump would handle 16psi no worries, I knew a guy in the US putting 18psi in through using a bigger Fass lift pump.
If fuel was getting into the engine there is another issue.
 

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1989 GQ TD42 wagon
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Try installing a low pressure (make sure you can blow through it, and that it does actually work!) check valve in the fuel delivery line. Just cut the soft line and put it in.
 
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