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Fuel tank cleaning

2K views 8 replies 4 participants last post by  12pulls 
#1 ·
I have gone through 2 high pressure fuel pumps on my 6L PFI engine in less than 60 hours total run time. All the plumbing looks good, low pressure pump working fine, etc so all I can come up with is that there is something leaching out of my fuel tank that is causing the problem.

The boat is an '87 Alumaweld formula V so there could be significant build up of varnish and other crud in the tank. Any good ideas on how to clean it out - if not cleaning, I will end up replacing the tank rather than keep putting in $300 fuel pumps.
 
#2 ·
Have you checked the fuel pressure while running? Could be a bad fuel pressure regulator. I had a similar issue on my 8.1L and ate 3 HP fuel pumps. Fuel pressure was all over the place until the regulator was changed. :twocents:
 
#3 ·
Hey Water Dog, didn't even know there was a fuel pressure regulator. Can you tell me where it is located on your 8.1L? What's it look like, etc.

Thanks for the idea - don't really want to pull the seats, floor, etc to replace the tank unless I really have to! Very annoying problem though - the last one failed on me at the boat launch on Vancouver Island as I headed out for a week of fishing/camping. Ended up using my kicker all week!
 
#4 ·
On my 8.1 it was on the back end of the engine, on top. Follow the fuel lines or rails and you'll see it. It's about 1.5" in diameter. Looks similar to this....



Get a fuel pressure gage and check that first. Pressure should be constant at a given RPM.
 
#5 ·
Visit with KEM. With the 10% ethanol content, there are vapor lock up problems with high pressure fuel pumps. With the engine inside the dog house, heat build can cause the ethanol to vaporize. This happens alot when the engine has been shut off hot and not restarted for a number minutes. Ethanol vaporizes at 130 to 135 degrees F. The vapor inside the fuel pump does not allow the fuel pump to work. Engine runs rough and it appears the fuel pump has failed. Easy solution is to cool down the fuel pump and get the ethanol back to a liquid.

It takes a few minutes for this to occur. It is enough of a problem that KEM is very much aware of it and can provide hints to help.
 
#6 ·
Might also find someone with a "techmate" and scan for any codes.

KEM has a fuel cooler that works awesome to cure vapor lock due to the the new crap fuel. KEM gave me one under warranty a couple months back. Vapor lock is easy to recognise and it will not eat a fuel pump. I'm not sure if it's related but I also lost several injectors, replaced the wire harness, replaced the MAP sensor and throttle position sensor as well.

I cured all those issues with a re-power and no longer have to worry about vapor lock and crappy gas. I now burn half the fuel and it's cheaper too. :D
 
#7 ·
Thanks for all the suggestions guys! I haven't scanned for codes, but the fuel pumps that have gone out are totally locked up. Putting 12v power to them results in a single click sound and then hot wires! KEM hasn't been too helpful so far, replaced the first one under warrantee, second one was on my dime.

WaterDog, did you repower with diesel?
 
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