Engine/Transmission (1994 - 1998) Timing Advance

[DogDiesel]

Finally got around to hooking up the electric fuel pump on my truck, which was an absolute requirement when my truck had a 6. 5L TD in it.



I figured I'd not need it, since the cummins has an awesome low pressure fuel pump. Wrong.



It runs quieter now, smoother and just drives sweet. Less vibration, idles better. If I'd only known.



Question: What makes for the timing advance on the 12V 5. 9L? Is it pneumatic off vacuum, or does fuel pressure affect it?



My truck feels like the timing is changed.



Does fuel pressure slightly alter timing?



Wayne

 

[ndurbin]

12 valves dont have the variable timing. their locked at whatever it is set at (stock is around 12-13*).



Sounds like it was just starving for fuel.



Nathan

 

[Joe G.]

Do you have a fuel pressure gauge?

 

[DogDiesel]

Yes, I have a fuel gage. No it was not starving for fuel. I replaced every line from the steel forward. It pulls near the same. Boost pressures about the same, maxing about 35-36PSI.





I suspect the pump itself could have served as a partial restricter, but I have towed heavy with it before, and it pulled well. Prior to replacing all rubber lines, I had restriction, and I could tell the difference pulling. I went with a size larger on the rubber.



Hopefully, mileage will remain the same or get better.



Thanks

 

[Cooker]

Did you remove the OEM lift pump and or fuel heater? What fuel PSI numbers are you seeing now?

 

[DogDiesel]

No, the OEM lift pump is still there. There was no fuel heater.

I saw vacuum before the pump, and correct pressure at idle after pump. Same# now.



Don't get me wrong, I like the way it humms now. Don't think the electric pump affected pressure, but it may have effected volume. Either way--good.



ndurbin answered my question.



All THANKS.

 

[Cooker]

Thanks for the reply.



Fuel pressure on a 12v should be 20-22 psi at idle. I would consider checking your overflow valve and see if it needs replacement.



No fuel heater? What year truck did you pull the motor out of? I was under the impression that all 6BT Cummins engines had a fuel heater, at least in a Dodge applicaiton I'm pretty sure they do.