The Official 1HD-T/FT Fuel Pump Mod Tuning Thread (5 Viewers)

[remy]

I understand the approach. But the problem is not in the guide pin so a larger diameter wont help you.
The problem is when you turn in the main screw (which is nessesary to get top more end fuel) the whole mechanism moves and you just cant tune it back with the afc mechnism. When you screw in the main screw far enough, you'll come to a point that the whole afc is ruled out. Besides, to tune down 1mm on the main screw you have to decrease the afc 2mm. This ratio is built in in the fulcrum lever. My new lever has different ratio's.

I should have been done other things today but was to eager to try some mods in the pump head. Took a 1hdt manual with intercooler and fast spooling turbo fitted (std rebuild pump, so no new fulcrum lever in here). I wasnt able to get afrs lower than 27 on high rpm (that s on 30psi boost from about 1800rpm) before without having loads of smoke on low end.
After making mods and do some tuning today I can get now AFRS of 1:20 all the way to the redline on full boost and only having 18 from idle! So the main screw is turned in a lot, almost on max.
Happy now, the truck already wasn't slow but is now seriously quick (0-60 in 10.5-11 secs)

 

[IanB]

This thread should be a sticky, lots of new threads are made that could just as easily have been asked in here, so as to keep as much relevant info in the same place as possible. If this was at the top of the forum I'm sure it would get a lot more traffic.

 

[mudgudgeon]

This thread should be a sticky, lots of new threads are made that could just as easily have been asked in here, so as to keep as much relevant info in the same place as possible. If this was at the top of the forum I'm sure it would get a lot more traffic.

Agreed. There also a good chunk of this thread that gives a good guide for base lining and trouble shooting current tune.

 

[Lws80]

So after 5 years and 55 pages we aren’t any closer to finding a decent fuel pin to replace the standard??

 

[Lws80]

Anybody used RC springs or wastegate springs for the boost comp? I’m probably doing this the hard way but I like the range and data you get with them. Got a feeling the RC springs are going to be too small and the wastegate springs will be too big tho

 

[Dargieboy]

I'm new too mud8 but just started to play around with my 1hdt put a badboy gturbo and a intercooler played with the pump abit but seems to lean out after 15 psi I seen afew people play baround with the aneroid rod so I took some offand seems to be a lot better but new looking for a blank rod or after marked rods higher boost 1hdts thank guys

 

[zipdoa]

I have been working with my rebuilt fuel pump/1hdt and found that the max fuel screw is turned up to the point where I can't reduce idle any more. If the max fuel screw goes up any higher, the truck will rev itself up while in neutral/park. Any tips on reducing idle while increasing max fuel? Is this a limitation of the 1990-92 injection pump?

 

[Tapage]

I have been working with my rebuilt fuel pump/1hdt and found that the max fuel screw is turned up to the point where I can't reduce idle any more. If the max fuel screw goes up any higher, the truck will rev itself up while in neutral/park. Any tips on reducing idle while increasing max fuel? Is this a limitation of the 1990-92 injection pump?

You can't .. or at least in my Pump / experience ..

and got to be honest, when I was at that point

the max fuel screw is turned up to the point where I can't reduce idle any more

I had more than enough fuel to see my EGT's flying faster than my RPM at 24 PSI with no air filter on .. ( water / meth injection on too )

So I never wonder for " more " fuel at that point ..

 

[Dargieboy]

I'm at the same point idle is at 900-1100 rpm but I can still turn my idle screw back but still not getting enough fuel ATM egt is sitting around 300-350 but very sooty at take off not to bad during lower gears but seems to lean abit out at high way speed it's a auto with cross country intercooler and gturbo bad boy

 

[Tapage]

my pin ..

 

[Dargieboy]

Dam that's a sex curve iv taken some out of mine but may need to do more

 

[dan1554]

Dam that's a sex curve iv taken some out of mine but may need to do more

I’d show my pin but I’m afraid you guys would make fun of me.

 

[Dargieboy]

I’d show my pin but I’m afraid you guys would make fun of me.

Nah mate so us what Ya got and what it goes like when I fly back home from work I'll put mine up before and after I take some more out of it

 

[surfari-LC80]

What is the rough length and diameter of the stock 1HD-T aneroid pin and the diameter of the follower pin? Gonna get some 4130 and 4140 round bar and see what happens.

 

[Mcreight911]

my pin ..

If u make the deepest part of the grind higher on the pin you'll get smoother transition, easier to tune fuel ramp in . The idea is to have it deep enough to max the follower pin travel. And rather than the reverse taper (Toyota overboost protection style) after the deepest part on your pin just make a step 90o to the pin . That way it won't de fuel with a slight over boost it will just stay in the max position . Kind of like the pic

 

[Tapage]

That way it won't de fuel with a slight over boost it will just stay in the max position . Kind of like the pic

noted .. makes sense ..

 

[mudgudgeon]

What is the rough length and diameter of the stock 1HD-T aneroid pin and the diameter of the follower pin? Gonna get some 4130 and 4140 round bar and see what happens.

Diameter is 10.9mm.

Can 4130, 4140 be hardened? Standard pin is case hardened and polished

 

[surfari-LC80]

Diameter is 10.9mm.

Can 4130, 4140 be hardened? Standard pin is case hardened and polished

Short answer is yes 4130 and 4140 can be hardened. see:
https://www.secowarwick.com/wp-content/uploads/2017/03/HeatTreatingDataEBook.2011.pdf
Alloy Steel Heat Treating Normalizing, Annealing Temperature Table Chart | Engineers Edge | www.engineersedge.com
heat treating 4130 steel - Metal and Metallurgy engineering - Eng-Tips

1st and foremost, Ill have to Rockwell test the stock pin and see where we need to be in terms of hardness. I'm not sure if my brain is working right but i remember back reading this thread and saw someone say the pin is 4130 steel.

anyone know the diameter of the follower pin? the reason I ask is because I want to know how many profiles/ramp curves I can mill into 1 aneroid pin.

 

[mudgudgeon]

It's small, I'd guess 4mm, but have had no reason to measure it.
I think you'll struggle to get more than one taper onto a single pin due to depth of cut

 

[remy]

4mm