Engine/Transmission (1998.5 - 2002) Is this the VP 44

[lukesdiesel]

I have noticed that It seems like I have no top end power. I can have my comp set on 5X5 going up a 4% grade and I cant get the truck over 85mph. When in running 70mph and I lay the hammer down my transmission doesnt down shift like it should.

 

[blacksheepdiesel]

What is your fuel pressure when under load like you describe? If it is low then the lift pump could be the cause. If not, could be the VP44. What boost do you show when in that situation? Checked for boost leaks? Any codes?



Godspeed,

Trent

 

[Timbeaux38]

You throwing any codes?

Could be a bad sensor... . or a bad Comp

 

[lukesdiesel]

I have installed a Holly Blue pump so I know the VP is getting fuel. My boost is around 34psi when this occurs. I have also used a scan tool and I don't have any codes. My EGT's are around 1100.

 

[blacksheepdiesel]

Luke,

If you do not have a fuel pressure gauge that reads post fuel filter then you do not know what fuel pressure is reaching the VP44. My pressure is monitered right before the VP so I know when the fuel filter needs changing. My guess is the fuel filter is the problem.

Godspeed,
Trent

 

[brianv31]

Has your fuel filter been replaced recently?

 

[lukesdiesel]

Filter was changed about 5K ago... My fuel pressure is 10psi at Idle post filter... ...

 

[telliott]

10 psi at idle? with a holly blue? i would think it should be higher than that. what are you seeing at WOT? i would start to get uncomfortable with anything to much below 10

 

[lukesdiesel]

Im going to check my APPS Signal Voltage.

 

[brianv31]

10 psi at idle? with a holly blue? i would think it should be higher than that. what are you seeing at WOT? i would start to get uncomfortable with anything to much below 10

I'd have thought so too, but my neighbor put a Holley blue on his '02 about 6 weeks ago and sees about the same at idle (he has 1/2" fuel lines). 10-12 psi when the fuel warms up.

 

[lukesdiesel]

Truck pulls hard until Overdrive... .

 

[AFarmer]

Change your fuel filter - ULSD is breaking stuff down in tanks and lines and causing filters to clog.

 

[GiesJ]

My EGT's are around 1100.

This seems pretty low for a comp on kill. Just driving around town on 5x5 what sort of smoke are you seeing?

 

[lukesdiesel]

It pours the smoke at WOT on take off... . then clears up

 

[lukesdiesel]

Im sending my comp into Edge to have it tested. Today I was fooling around with the settings and I could hit 95MPH, 1300egt's and 40psi boost. My box is also making my truck miss on the lower fueling settings.