Need Help, Fuel draining back

[alexx1060]

hey guys, 3 days in and I'm running out of options.
2011 KW T660
CM871 with electric low-pressure pump

Current symptoms:

Turn key to Ignition ON position, fuel drains into tanks from both Clear Housing filter (many air bubbles clearly visible) and from the on Engine filter. Seems to be free flowing as if someone is just pouring it out.

Tried Bypassing the Chassis filter, same result.

Can hear the low-pressure pump motor running for sure.

Any advice would be appreciated!

[schISM]

Are you getting any cel? How's the engine running? Not entirely sure but if the low pressure pump is running it's gonna return fuel to your tanks, I'm thinking it was designed that way.

[alexx1060]

engine runs good, yea low pressure pump primes the engine via electric motor.

(09-10-2016 )schISM Wrote:  Are you getting any cel? How's the engine running? Not entirely sure but if the low pressure pump is running it's gonna return fuel to your tanks, I'm thinking it was designed that way.

[alexx1060]

did a soft bypass by disconnecting the motor from power, engine was able to start but got same results as before

(09-10-2016 )schISM Wrote:  Are you getting any cel? How's the engine running? Not entirely sure but if the low pressure pump is running it's gonna return fuel to your tanks, I'm thinking it was designed that way.

[schISM]

So the engine wouldn't start and your seeing fuel being returned to the tanks when you cycle the key switch and think thats why it wont start?

[alexx1060]

well it won't start because there's not enough fuel, either in the main filter on engine or in the clear one or both.

after cycling the key switch, we took off the main filter to see if there's fuel in it and there's less than half which is not enough.

(09-10-2016 )schISM Wrote:  So the engine wouldn't start and your seeing fuel being returned to the tanks when you cycle the key switch and think thats why it wont start?

[schISM]

Did ya fill both filters and see if the engine would pick it up again?

[Signature620]

Lift pumps can sound normal but be very weak at the same time. If you tip fuel into the IFSM inlet, does it suck that in?

[Rawze]

(09-10-2016 )alexx1060 Wrote:  hey guys, 3 days in and I'm running out of options.
2011 KW T660
CM871 with electric low-pressure pump

Current symptoms:

Turn key to Ignition ON position, fuel drains into tanks from both Clear Housing filter (many air bubbles clearly visible) and from the on Engine filter. Seems to be free flowing as if someone is just pouring it out.

Tried Bypassing the Chassis filter, same result.

Can hear the low-pressure pump motor running for sure.

Any advice would be appreciated!

WTF??!?! Are you trying to say?

Clear housing filter??-- EH??!? Do you mean your DAVCO FILTER ??? -- THERE IS NO DRAIN LINE FROM THE DAVCO BACK TO THE FUEL TANKS!!!

on Engine filter??-- EH??!? Do you mean your THROUGH-FLOW FILTER? ??? -- THERE IS NO DRAIN LINE FROM THE THROUGH-FLOW FILTER TO THE FUEL TANKS!!!

===========

In an attempt to descern what you are trying to say...

Are you saying that there is LESS FUEL in both the davco AND the through-flow filters after you turn the key and the electric fuel pump runs?

Will the engine run or not?-- Does it run erraticly?

What are the circumstances surrounding this problem?? -- Engine suddenly loose power? -- Were you changing the filters? -- HOW DID YOU END UP WHERE YOU ARE AT WITH IT?