lack of power under load

[KRaiskio]

So after some searchin and lots of diagnostics and replacement Im at a loss. The truck will start normally and at a stand still run right up to 2500 rpm easily. If I try going down the road it breaks up and has no power. I replaced all the filters ( spin-ons), in tank hose, and all the plastic return lines due to sucking air. I pulled all the injectors and cleaned them. Checked the plunger on the HH and in tank pump is working. While running I cracked each inj line at the inj itself and starts to stumble a lil or skip. Drined the tank, cleaned and refilled w clean straight Diesel. I also tried to turn up the fuel just to see what would happen with no change. Im hoping someone may have some insight before I spend the money on an inj pump and or hyd head.

 

[Floridianson]

If you were going by the troubleshooting the465tm then you could put a pressure gage on the finials and see if you got the 4/ 30/70 psi. Sounds like you checked most things. The only trouble I have is I don't do my own injectors. They need to be popped and checked for spray. New injectors pop at 3500. Some can be adjusted some can't.
Did you pull the intank pump out just for a look sea?
Just because the plunger is going up and down does not mean it is going compleatly up and down eather or that there is no problem with the head.

 

[KRaiskio]

I pulled the intank pump and replaced that rubber line no gunk or anything. I have to get a gauge to check my pressures. I brought the injectors to shop I used to work at they bench tested them for me and said they were good.

 

[Floridianson]

Ok then you did good. Lets check pressures.

 

[73m819]

How about draging brakes

 

[jasonjc]

All 3 filters? And did you check the line that goes from the frame mounted filter around the front of the eng to the pump? That line seems to get crushed and limtes flow.

 

[KRaiskio]

Yes all three filters, cleaned what little was on the screen on intank pump all lines are good and tight. Brakes arent hung up and seems to break up like sucking air or lack of fuel when going down road. Where should I check fuel press? After secondary fuel filters Id assume. Something doesnt look right as far as fuel lines go but I have about 6000 miles on her before I had any problems.

 

[phil2968]

What about valve adjustment?

 

[islandguydon]

Did you fuel up with Bio Diesel..? That will do it.

 

[Squirt-Truck]

Sounds like low boost pressure refer to checking pressures from Floridianson, this is critical for the HH to fill and be able to consistently deliver fuel under load. BUT, this shows itself as skipping and breaking up under load when the main fuel line either from the filters to the compensator or compensator to HH is cracked. (Generally at the ferrell) Under load the HH will literally pull air into the system and that acts like a skip.
Last stop is the overflow valve but, lets check pressures first.

 

[KRaiskio]

That was my next step to just replace all the primary fuel lines just so I don't have to worry. I don't see any air in the lines but I'll pry just replace the lines when I check the pressures hopefully later today. Thanks everyone for the quick responses!

 

[hemichallenger]

I would check the timing.

 

[gimpyrobb]

Nah, not a timing issue. Make sure the filter housings are on right. High speed can suck air into them if they are off just a little.

 

[KRaiskio]

Yeah I pulled those all apart too just to be sure.

 

[KRaiskio]

So quick update. Have 7psi where main line goes into HH. What has me concerned is that on the back of the IP there are two fittings with just loops of hose going back into itself. I'll try and get a pic posted soon.

 

[phil2968]

That's just the hoses that used to connect the fdc. They used them to plug openings.
Is the pressure with it running and at what rpm?

 

[KRaiskio]

The pressure was just the in tank pump. I took the fitting off going into the HH from the filters and put a gauge on there. I will try one inline there I guess tomm. What should the pressures be and where?

 

[phil2968]

Check out post 2 in this thread. James listed them.

 

[Floridianson]

=KRaiskio where?

I could tell you to read my post again but once again at the finial fuel filters bleed screw. That will be 30 at idle and close to 70 at the upper end of the rpm. Happy hunting

 

[KRaiskio]

Sitting here w the pressure gauge in it ( which I may install ) its around 7 psi w switch on, 15psi at idle, and goes up to 70 psi at wot except takes a while to rev up