BJ74 13bt fuel pump adjustment (1 Viewer)

[Kris 74]

Hello everyone ,
My name is Kris , I have a 1986 bj74 with 13bt and I'm trying to adjust the fuel pump for slightly raised boost ( currently 12-14psi )
After searching and reading all available information I haven't found a way to just increase on boost fuel . 2 turns in of the main fuel screw gets the job done up top but idle is smokey .

Has anyone succeeded to do this ? I see other pumps have a aneroid pin in the boost compensator that can be ground , maybe the 13bt is the same ?

Cheers for any information

 

[FJBen]

Hello everyone ,
My name is Kris , I have a 1986 bj74 with 13bt and I'm trying to adjust the fuel pump for slightly raised boost ( currently 12-14psi )
After searching and reading all available information I haven't found a way to just increase on boost fuel . 2 turns in of the main fuel screw gets the job done up top but idle is smokey .

Has anyone succeeded to do this ? I see other pumps have a aneroid pin in the boost compensator that can be ground , maybe the 13bt is the same ?

Cheers for any information

Here is a great post on all the adjustments you can make on a 13bt.

13B-T Fuel Adjustment - Power Increase; ANSWERED! - https://forum.ih8mud.com/threads/13b-t-fuel-adjustment-power-increase-answered.256621/

The boost compensator adjustment is what you want if you are wanting to increase fuel under boost.

 

[Kris 74]

Here is a great post on all the adjustments you can make on a 13bt.

13B-T Fuel Adjustment - Power Increase; ANSWERED! - https://forum.ih8mud.com/threads/13b-t-fuel-adjustment-power-increase-answered.256621/

The boost compensator adjustment is what you want if you are wanting to increase fuel under boost.

Thanks for commenting , I have read the said thread many times .
And adjusted that screw many times . To my understanding and experience it does not add more fuel under boost . All it does is delay or advance when the additional fuel gets added .
The factory boost compensator adds enough fuel for the factory 6psi boost no more .

Unless I got it all wrong

 

[Hulsty]

Did you also increase the fuel via the guide bushing?

 

[Kris 74]

Did you also increase the fuel via the guide bushing?

I have not tried the guide bushing adjustment . My understanding of that adjustment is, its the spring tension behind the diaphragm . So loosening the tension will allow fuel increase with less boost but still not more fuel on boost , just earlier .

 

[FJBen]

I have not tried the guide bushing adjustment . My understanding of that adjustment is, its the spring tension behind the diaphragm . So loosening the tension will allow fuel increase with less boost but still not more fuel on boost , just earlier .

So is your goal to get more power?

Are you running the stock turbo?

I barely have my fuel turned up but I’ve put a Holset HE221w and mine boosts fast and hard up to 20psi hardly any smoke.

Drives way more modern feeling than the original turbo did. I haven’t even touched any other adjustments other than turned the max fuel up 1.5-2 turns.

 

[Hulsty]

I have not tried the guide bushing adjustment . My understanding of that adjustment is, its the spring tension behind the diaphragm . So loosening the tension will allow fuel increase with less boost but still not more fuel on boost , just earlier .

Correct, so if you want more max fuel, screw in the max fuel screw more, not sure what your issue is? On mine I have the max fuel screw all the way in.

 

[Kris 74]

Correct, so if you want more max fuel, screw in the max fuel screw more, not sure what your issue is? On mine I have the max fuel screw all the way in.

I have screwed in the max fuel screw in 2 turns . But I was under the understanding that screw increases fuel accross the whole range , including idle .
My issue is , it's very smokie at idle and before boost when I adjust the max fuel screw alone .

I would think your max fuel screw in all the way would smoke a lot at idle and before boost ...
Maybe it's very noticeable for me as I start it in the shed and it literally smokes out my whole shed haha .
When I turn the max fuel screw out 2 turns its much better but no power ...

i guess this is just the limitations of a mechanical pump..


Yes it's a standard ct26 , 3inch turbo back , pre turbo egt .

 

[FJBen]

Yes it's a standard ct26 , 3inch turbo back , pre turbo egt .

A standard ct26 is laggy. It’s too big for the 13bt. It will be Smokey when adding more fuel.

Also if its that Smokey at idle with only 2 turns, it could be the pump or injectors. When’s the last time the injectors were serviced?

 

[Kris 74]

A standard ct26 is laggy. It’s too big for the 13bt. It will be Smokey when adding more fuel.

Also if its that Smokey at idle with only 2 turns, it could be the pump or injectors. When’s the last time the injectors were serviced?

Yes the ct26 is laggy .
The injectors where reconditioned 20k ago (as per receipt only the injector body was reused)
The pump is untouched 365k on the clock currently .

so I guess there isn't a way to only increase on boost fuel, with out adding fuel at idle and before boost ...

 

[FJBen]

Yes the ct26 is laggy .
The injectors where reconditioned 20k ago (as per receipt only the injector body was reused)
The pump is untouched 365k on the clock currently .

so I guess there isn't a way to only increase on boost fuel, with out adding fuel at idle and before boost ...

Injectors should be good. I’m sure the pump could benefit from a rebuild, but not sure I’d tear it down without it showing some issues or leaking.

I think you would greatly benefit from a turbo upgrade. That would improve the drive ability and power curve of the 13bt quite a bit.

I rebuilt my 13bt, rebuilt the injection pump, injectors and a rebuilt ct26 turbo so I had about as new/fresh install as possible. It ran good but laggy. Putting the he221w transformed it, runs so much better.


Gturbo - bolt on, highly recommended on here
Munro racing - less used (pretty much Aussie only but great reviews) bolt on
Kinugawa - ok reviews, make sure to get the right model as they have lots of options that may or may not work. Cheaper than the above, should bolt on.

Others are more DIY.
Holset HE221 - get the right size and it pulls like crazy and fast. Cheaper overall than above but will need adapters, exhaust work etc.
tdo4hl - basically the same as a he221. Many different options. DIY.

 

[Kris 74]

Injectors should be good. I’m sure the pump could benefit from a rebuild, but not sure I’d tear it down without it showing some issues or leaking.

I think you would greatly benefit from a turbo upgrade. That would improve the drive ability and power curve of the 13bt quite a bit.

I rebuilt my 13bt, rebuilt the injection pump, injectors and a rebuilt ct26 turbo so I had about as new/fresh install as possible. It ran good but laggy. Putting the he221w transformed it, runs so much better.


Gturbo - bolt on, highly recommended on here
Munro racing - less used (pretty much Aussie only but great reviews) bolt on
Kinugawa - ok reviews, make sure to get the right model as they have lots of options that may or may not work. Cheaper than the above, should bolt on.

Others are more DIY.
Holset HE221 - get the right size and it pulls like crazy and fast. Cheaper overall than above but will need adapters, exhaust work etc.
tdo4hl - basically the same as a he221. Many different options. DIY.

Thank your very much for the advice . I agree with everyone, ct26 is slow spooling out of date turbo, I think mine does something around 2000-2200 .

I like the idea of the holset if that's the most responsive . Not afraid of some fab , after all I did make the whole exhaust from scratch .

Cheers