Losing Power Uphill & Under Load (1 Viewer)

[92HDT]

I bought a 1992 HDJ-81 while in Japan and recently had it imported to Hawaii. Since I’ve gotten it, my injection pump busted and 1 of my injectors blew.

As a result I have had the following done:
1. Injection pump professionally rebuilt to factory standards
2. New timing belt put on
3. All new injectors installed

Since I have had it back on the road, I lose all power going up hill or under load.

Any suggestions of what it could be? Could it be a lack of fuel? Bad fuel?

 

[franklin40]

do you have a boost gauge to know if your turbo is making proper boost? also if you had your pump rebuilt did they tune it properly when reinstalled? could be your fuel is turned way down. boost and egt gauges are nice additions if you’re going to play with out of factory settings. if it’s blowing lots of smoke when under load probably don’t have enough boost. if it’s totally clear when you first step on it then probably not enough fuel. at least that’s been my experience. way smarter people than me will hopefully chime in too

nice looking cruiser too! what island are you on? looks like kauai but what does a flat lander like me know

 

[duncanrm]

Does it idle roughly when parked on a slope?

 

[David*BJ70]

Cheap thing first --> Fuel filter

 

[92HDT]

We're on Oahu. Love it so far. I have found some pretty good off-road trails too.

The turbo is the one thing I have not checked in depth yet. But I brought the pump to a reputable injection pump specialist. He said he set it to the factory settings. I've been thinking about increasing the fuel intake slightly and see what happens. I just don't want to flood the engine.

A boost gauge is much needed. Probably my next purchase

 

[kevin in okinawa]

We're on Oahu. Love it so far. I have found some pretty good off-road trails too.

The turbo is the one thing I have not checked in depth yet. But I brought the pump to a reputable injection pump specialist. He said he set it to the factory settings. I've been thinking about increasing the fuel intake slightly and see what happens. I just don't want to flood the engine.

A boost gauge is much needed. Probably my next purchase

EGT gauge then a boost gauge, THEN you may mess with fuel and boost settings. not until then. diesels are not gassers, you need to have those two measurements before you go and mess everything up real bad.

You must be a Hair Force guy, right?

 

[franklin40]

you wont flood your engine if you turn the fuel up. you’ll fry your turbo. increase fuel equals increased EGT if you don’t boost it to match. don’t just play with your fuel unless you have an egt gauge.

 

[MonsterCruiser]

Maybe lack of fuel. Check your pick up in the tank.

HDJ81 Fuel suction hose/filter, wow! - https://forum.ih8mud.com/threads/hdj81-fuel-suction-hose-filter-wow.437257/

Doesn't cost anything to check it before you start replacing more parts.

 

[perrobravo]

I'd echo the absolute need for a properly placed EGT probe and gauge before tweaking fuel delivery or boost.

With that, after reinstalling my injection pump after a professional rebuild (making sure to get pump timing right), I had similar symptoms on my HDJ81...low power uphill and under load. Following instructions in the official fuel pump thread, I adjusted spring tension in the boost compensator and solved the problem. Essentially the aneroid pin wasn't moving enough and therefore wasn't allowing enough fuel at higher speeds/load. Simple fix with a hex wrench and a flathead screwdriver to spin the star wheel. Again, don't do this without an EGT gauge.

From there I slid down the slippery slope of installing a more aggressive pin, increasing boost, and adding fuel and went way beyond stock performance. Now I can even leave the slow lane and (gasp) actually pass people on hills.

 

[Skippyd]

My fuel filter housing was sucking air and during that time I would have some power issues going up steeper grades.

 

[roscoFJ73]

Injection pump professionally rebuilt to factory standards

He said he set it to the factory settings.

Just for clarity, did he open the pump up and replace parts or just adjust the controls? Normally when they rebuild a pump and replace worn parts the bill is in the thousands. And the pump is always bench tested and the pressure is observed and recorded.