Adjusting fuel/air mixture on B engine (1 Viewer)

[Rusto]

I've read some interesting threads on here and perused the engine manual for my B motor, but I couldn't find what I was looking for, so I thought I'd ask the experts.

When my B motor is running well, it's running rich with a steady stream of black smoke out the exhaust when under "hard" acceleration. I'm at 6,500 feet and plan to be up between 10,000 and 12,000 feet this summer regularly. I don't have an HAC yet nor do I have a pyrometer, but I know it's running rich. I've read somewhere that I can reduce the fuel going into the cylinders manually. And while it's not nearly as good as a functioning HAC, it would better than having it run rich all the time until said HAC can be procured. My old Toyota PU had the HAC installed and it was a godsend up here in the mountains.

Meanwhile, I don't know how to lower the amount of fuel being delivered. Can someone help a brother out?

 

[DEADSALT]

hint - it involves your right foot

 

[Rusto]

@DEADSALT - I always appreciate your input.. Definitely makes a difference. I get about halfway to 2/3rd down on the pedal and that's when the black smoke starts pouring out. I'd prefer to be able to mash the pedal all the way to the floor before black smoke comes out...

So.. is there a way for me to change the ratio of fuel being delivered to fuel pedal mash?

 

[duncanrm]

There's a Wide Open Throttle Max Fuel Screw... if you're happy to manually adjust it you can dial back fuel at High Altitudes, and return it to normal at sealevel.. you'd have to be pretty careful with the number of turns (maybe even less than 1) that you're doing. This is the screw on the 2H.. the B will have the same screw. A working HAC is an option, other clever people have rolled their own solution.

 

[Rusto]

That's what I'm talking about @duncanrm Help from 8,796 miles away. MUD Nation!

for the most part, I'll always be above at least 5,000 feet so I think I'm safe to manually adjust it for now for higher elevations. I'll adjust a little, drive some, adjust a little, drive some, until I get it right, then leave it there for now. I would like to get a functioning HAC on it at some point, and a turbo.. and a 5-speed... Add it to the list!

Thanks

 

[Diesel42]

The ultimate correction is a turbocharger

 

[Rusto]

@Diesel42 - hopefully, a turbo is in my future, but there are a lot of other things on the list first, that's for sure.

@duncanrm - I don't think the B engine injection pump is the exact same as the H, but I do think I've identified where I can adjust the fuel delivery amount on mine.
Here's a pic from the FSM

Does that look right?

 

[duncanrm]

That is going to adjust fuel at every throttle position. I know the same is available on the 2H but I have never had the courage to play with it. I would tread very carefully. Can you send a photo of your pump from a couple of angles?

 

[Rusto]

I may be okay with adjusting fuel at every throttle position. I am trying to adjust for the elevation. I'll almost always be above 6,000 feet around here, so that may be an option.
Anyway, thanks for your help @duncanrm . Here are some pics.

 

[DEADSALT]

before you start playing with the IP,
one might consider to continue baselining an unknown mileage B engine.

 

[Rusto]

I agree with you on that @DEADSALT . It doesn't look like it's ever been opened. I'm more building up the knowledge base as I go through it at this point.

I've changed all the fluids, filters and glow plugs. Adjusted the idle.

Next step is a compression test and possible valve adjustment.
Working on getting the fuel clean as well, which may require removing and cleaning the tank and blowing out the fuel lines.
Then I'll change the diaphragm (new part is on the shelf)

All my random threads on slightly different topics here lately have been me getting to know the truck and get it somewhat sorted engine-wise.

I do know that when it's running it's best, it's running rich.

when all of the above has been done and if it's still running rich, then I'll start adjusting the fuel/air mixture.

I can get ahead of myself sometimes...

Russ

 

[DEADSALT]

when you cleaned the prefilter on the IP,
how did it look;
crusty/rusty/algae coated

have you removed/cleaned/flushed the tank yet

hoses on throttle body checked and clamped (Pedal is linked to throttle butterfly not fuel)

EDIC functioning as intended ( 75 have an EDIC?)

change diaphragm

ensure you have clean fuel delivery


I would definitely adjust valves, they’ll be out of spec and It’s easy


and the biggest thing is to have your injectors serviced/rebuilt.



then,
lean out your IP with trepidacios caution!

 

[Rusto]

Pre-filter was clean and shiny. No rust, algae, etc.
Installed the inline filter to see what was coming through the line and it was rusty at first.
About 3/4 though this tank. I'm going to change out the inline and OEM fuel filter one more time on this tank. I'll confirm that it still has crap in it.

When that is the case, then I'll drain, pull and clean the tank.

Hoses seem to be in good shape, but I'll check again.

Then it's the next steps you describe.

May even try to source an HAC before I start messing with the fuel ratio..

 

[Rusto]

Anybody have a good source and estimated price for getting injectors serviced/rebuilt?