Loss of fuel pressure?

[Turbo Johansen]

Hey

i have an 2013 m800 with boondocker racegas turbo, it will not run on more than 1/4 throttle, i read about 44psi from pump. Changed pump and pickup assembly and its still the same. Testes both pumps outside tank without regulator and they deliver 50+psi.
throttle safety switch and key is disconnected. Only proarmor tether connected.

when i hit the throttle it will go to maybe 6000rpm before it looses fuelpressure, not sure its lossing it but is seems like its the problem. Any tips?

 

[kidwoo]

6k rpm is also about where the powervalves open. Unless you're looking at your pressure gauge I'm sure fuel pressure dropping is the obvious problem. 44psi is fine.

 

[FFLH]

Stator is bad

 

[Turbo Johansen]

Can a bad stator cause loss of fuel pressure? Going to measure the stator now.

 

[Turbo Johansen]

Measured stator, everything is within specs.

 

[Turbo Johansen]

Tried running the sled with battery powering the pump. Everything works fine then, the pump is not recieving rigth amount of voltage. Changing regulator and stator next.

 

[kidwoo]

Tried running the sled with battery powering the pump. Everything works fine then, the pump is not recieving rigth amount of voltage. Changing regulator and stator next.

Heh. I just spliced in a new plug on my fuel pump for the same reason.

What's your voltage coming out of the harness at the fuel pump connection?

 

[Turbo Johansen]

Heh. I just spliced in a new plug on my fuel pump for the same reason.

What's your voltage coming out of the harness at the fuel pump connection?

I have 16.6V at the connector for fuel pump. Where did you splice the plug in?

 

[kidwoo]

I have 16.6V at the connector for fuel pump. Where did you splice the plug in?

Mine was 16.1v at the plug for what it's worth. My problem was that the plug was only forming an intermittent connection. My fuel pressure would drop and then return to pressure while jiggling the plug.

I just cut the power wires on each side of the plug and soldered in a two wire waterproof one. I just have two plugs now, one for power and one for the float.

 

[Old & slow]

I have 16.6V at the connector for fuel pump. Where did you splice the plug in?

If you actually have 16.6 volts then your regulator has failed, spec is 12-15V. With to high of a voltage current will drop.

 

[kidwoo]

spec is 12-15V.

Where did you find this?

 

[Old & slow]

Where did you find this?

Service manual. Usually a VR will fail with low voltage but i have seen them fail with over voltage, Either way if your 16 volts is accurate the VR is failed.

 

[Turbo Johansen]

Yes, VR is failed. Same result with new stator.

 

[Turbo Johansen]

Okey, results so far!
Changed :
-Stator
-main harness
-Voltage regulator
- fuel pump
- blended fuel regulator.

Still same result, 25psi fuel pressure.

any ideas?

 

[spoon]

Bad harness or grounds. Poor connection somewhere. Had similar issues on stock M8, intermittent pump voltage and after rerouting main harness and tightening/adjusting ground wires, problem was gone. Factory routing of main harness had some tight/stretched sections pulling on connectors. No parts replaced to correct it but lots of hours and hair pulling. Never stranded me but surprised I still have original pull cord. Problem was always worse hot.

 

[Old & slow]

Okey, results so far!
Changed :
-Stator
-main harness
-Voltage regulator
- fuel pump
- blended fuel regulator.

Still same result, 25psi fuel pressure.

any ideas?

This is starting to be an ignorant one, did you check the smart valves ? I bad ground will also cause issues. Is all the other electrical working right? There is also a wiring schematic on Country Cats site that may assist.

 

[kidwoo]

Problem was always worse hot.

Preach it brother!!!

 

[Turbo Johansen]

Going to rip out the main harness again to check and measure all wires..i will update the results.