The Official 1HD-T/FT Fuel Pump Mod Tuning Thread (9 Viewers)

[NielsC]

Hi all, I came across this mod for the VE pump:

What is a Boost Ring & do they work on Land Rovers? | 4Mud

How to install a Dynamic Timing Advance Spacer kit | Steg's Supplies

Basically it is a spacer that gives more travel to the dynamic advanced timing plunger in the pump wich advances the timing at higher revs for a better combustion.
Apparently it is a popular mod with the cummins and landrover crowd.
I also noticed my 1HDFT pump has an adjusting screw there.
Anyone have done this mod or played with the adjusting screw?

 

[ForealBoreal]

You in theory should be able to tune the boost comp and not even touch the max fuel screw to advance the pump.
Make sure your pumps timing (plunger stroke) is set correctly.
Then mess with the boost comp to give the desired results.

I really need to look into making a fuel pin kit.
Lid, rod and spring.

 

[mudgudgeon]

Hi all, I came across this mod for the VE pump:

What is a Boost Ring & do they work on Land Rovers? | 4Mud

How to install a Dynamic Timing Advance Spacer kit | Steg's Supplies

Basically it is a spacer that gives more travel to the dynamic advanced timing plunger in the pump wich advances the timing at higher revs for a better combustion.
Apparently it is a popular mod with the cummins and landrover crowd.
I also noticed my 1HDFT pump has an adjusting screw there.
Anyone have done this mod or played with the adjusting screw?

I was advised not to alter it. It would be set using a proper test bench.
There's so many other variables that can change the tune, I think it would be difficult to find a way of testing any change

 

[NRS91]

Hi everyone,
I am Nick from Steg's Supplies.
I am currently looking into whether our Dynamic Timing Advance spacer kit will work on the Denso and Zexel manufactured VE pumps.
If anyone has any pictures of their pump from the side installed on the Land Cruiser that would be helpful!

mudgudgeon by the looks of the Denso pump you have a "tophat" cover plate with an adjustable screw for the timing advance spring rate correct? So adjusting this would change the rate at which the timing advances with case pressure (and therefore engine speed).
This will probably be set in a similar fashion to the Bosch VE pumps calibration shims using a gauge that bolts to the other side of the pump.

When we install the dynamic timing advance spacer kit on the Bosch pump we also install a shim to maintain the spring preload and keep the timing advance rate as close as possible to standard while allowing the timing piston so travel its full travel within the casing giving us more overall timing advance.
On a standard engine this isnt required but on a modified engine with increased fuelling this allows for sufficient time for the extra fuel to burn completely, reducing smoke and EGTs while giving more bang for your buck.

If I can get my hands on a Zexel and Denso VE pump in the UK I will strip it down and see if my kit will work or whether it will need modification.

 

[remy]

Seems that a differend shimmed pressure control valve will control the internal pump pressure a lot better than the original one. Messing around with the timing piston wont help when there isnt sufficient pump pressure on the high output pumps. Measured the pressure a few times and it will drop a lot when you hit the throttle. Timing will drop with it as well.

 

[NRS91]

Seems that a differend shimmed pressure control valve will control the internal pump pressure a lot better than the original one. Messing around with the timing piston wont help when there isnt sufficient pump pressure on the high output pumps. Measured the pressure a few times and it will drop a lot when you hit the throttle. Timing will drop with it as well.

On the Bosch VE you normally suffer case pressure dropping (which retards the timing) when you have a weak lift pump or a lift pump that cant keep up with larger injectors.
What is the spec on the engine that you were seeing case pressure drops on? Do you know what the fuel inlet pressure was?
I am keen to learn more about the Denso/Zexel pumps and play spot the difference like you guys already have with the AFC cap.

 

[mudgudgeon]

@NRS91 don't know the answers.

I do know the zexel, and Denso pumps are essentially Bosch VE pumps, made under license.
I would expect them to be functionally the same, but parts may differ for model specific applications or ease of manufacture

 

[ForealBoreal]

Also the 1h* series with the ve pumps don’t actually have lift pumps either.

 

[NRS91]

Also the 1h* series with the ve pumps don’t actually have lift pumps either.

Ah right, that might be why you see timing shift when you floor it with the fuelling increased?
Bosch version likes a minimum of 3psi and a max of 15psi.
Do the Denso/Zexel pumps return a lot of fuel or not?

 

[remy]

On the Bosch VE you normally suffer case pressure dropping (which retards the timing) when you have a weak lift pump or a lift pump that cant keep up with larger injectors.
What is the spec on the engine that you were seeing case pressure drops on? Do you know what the fuel inlet pressure was?
I am keen to learn more about the Denso/Zexel pumps and play spot the difference like you guys already have with the AFC cap.

Yes that is right, but with a different regulator it is a lot less worse. Tested on 3 1HDFT engines, most std pump maxed out.
Same results so I dont think the pump is bad.

Took some pictures for you about the timing piston. I guess there is some room left, so the spacer might work IF the case pressure can overcome the spring pressure to take advance of the spacer. I dont know this and have to install a spacer to test it with the timing tool.
Anyway it is not limited by the rotating assy itself, the pin or neither by the ASCD.

On this particular pump there wasnt almost any movement of the timing piston. You can clearly see the damage of a weared piston. Fuel will slip past the housing so there isnt any pressure against the piston. I dont know if this is a common Toyota injecton pump problem. I have put another much more simpeler piston style in my own pump to avoid this. Seems that only Toyota uses this kind of piston.

 

[NRS91]

Yes that is right, but with a different regulator it is a lot less worse. Tested on 3 1HDFT engines, most std pump maxed out.
Same results so I dont think the pump is bad.

Took some pictures for you about the timing piston. I guess there is some room left, so the spacer might work IF the case pressure can overcome the spring pressure to take advance of the spacer. I dont know this and have to install a spacer to test it with the timing tool.
Anyway it is not limited by the rotating assy itself, the pin or neither by the ASCD.

On this particular pump there wasnt almost any movement of the timing piston. You can clearly see the damage of a weared piston. Fuel will slip past the housing so there isnt any pressure against the piston. I dont know if this is a common Toyota injecton pump problem. I have put another much more simpeler piston style in my own pump to avoid this. Seems that only Toyota uses this kind of piston.

Brilliant info there Remy!
The piston and cap are a different style to the Bosch ones but the piston protrusion at max travel looks very similar to the Bosch shown below.

This is what it looks like with the cap held in place on max travel:

And then finally here is the Bosch pump with one of my prototype spacers in:

Do you have any pictures of the inside of the cap on the Cruiser pump Remy?
I would be interested if the shim we use could be installed or whether that would prevent the spring locating properly?
May be able to install the shim inside the piston instead and keep the cap end as Toyota intended.

 

[ForealBoreal]

I believe I had Bosch plunger and cummins pump stuff fitted when I got a 12mm pump built by Okanagan Fuel Injection after the XXi pump grenaded itself

 

[GTSSportCoupe]

I've had an idea for a while now of developing an electronic controlled fuel pin for these VE pumps. Tuning the mechanical pin is just such a PITA. What do you guys think?

Basically an electronic actuator that fits in the same spot as the Boost comp cover/diaphram/pin/spring etc. It would be a 'bolt-in' solution. The actuator would have fine electronic control with feedback and ability to react quickly. It would have an electronic controller in the cab that could control all the same aspects of the pin that you are doing now with the starwheel, spring and cam. Basically, with some small knobs, you could adjust the start fueling (position of pin out of boost), adjust the fuel curve, and adjust the fuel cut limit. It would give complete control of tuning right from the drivers seat. Could even do like other tuners and get fancy with a few different maps for different applications (economy, power, towing etc.). What do you guys think? I design electronics for a living, and a good friend of mine designs mechanical for a living (machinist). He has an HDJ81, and we've been thinking about doing a prototype for his truck for quite a while.

 

[NRS91]

I've had an idea for a while now of developing an electronic controlled fuel pin for these VE pumps. Tuning the mechanical pin is just such a PITA. What do you guys think?

Basically an electronic actuator that fits in the same spot as the Boost comp cover/diaphram/pin/spring etc. It would be a 'bolt-in' solution. The actuator would have fine electronic control with feedback and ability to react quickly. It would have an electronic controller in the cab that could control all the same aspects of the pin that you are doing now with the starwheel, spring and cam. Basically, with some small knobs, you could adjust the start fueling (position of pin out of boost), adjust the fuel curve, and adjust the fuel cut limit. It would give complete control of tuning right from the drivers seat. Could even do like other tuners and get fancy with a few different maps for different applications (economy, power, towing etc.). What do you guys think? I design electronics for a living, and a good friend of mine designs mechanical for a living (machinist). He has an HDJ81, and we've been thinking about doing a prototype for his truck for quite a while.

It would be an interesting project but for the effort i would try and make a VE44 and VP37 hybrid so you have a 12mm 6cyl VP37 EDC pump

 

[Rock40]

Thanks to all who have lent their knowledge here, there's a ton of great information if you can wade through it all. I recently had my pump done but I hadn't attempted to tune it yet. What a PAIN to get access to the comp cover on the FT motor, damn. I ended up loosening everything including all the injection pump lines just to get the comp cover off. Without doing that, I had zero chance of even getting to the top plate screws.

Here's a few things that worked for me, I marked the star wheel with 4 different colors of paint pen to help me keep track of it's orientation. Each mark is approximately 90 degrees from the other.

I also compared aneroid pins between a HD-T and the FT. The FT has a significantly more aggressive fueling profile and is shown above with white paint.

The aneroid pin on my FT also had a single shim which I ended up leaving in place for now

Instead of a bike pump, I used a Snap-On radiator tester to manually add pressure to the compensator. It's VERY accurate up to 30 psi and worked great.

I backed the smoke screw all the way off and reduced the tension on the star wheel 1/2 turn (180 degrees). When it came apart, the aneroid pin was already at max fuel although the pin hadn't been ground yet for easy re-assembly. Testing it with paint revealed that it was just getting maximum fuel at 15 psi which is where my manual boost controller is currently set to. My hope is that the motor will be less smoky at cold idle then I'll start the tune.

 

[Rock40]

Fiddled around with a bit of tuning today. I've no idea where the main fuel screw is on this pump but just about WOT on a fairly steep uphill (4th gear) and it has enough power to completely roast the stock Aisin clutch with only 30,000 miles on it. Boost spiked to almost 20psi on a stock CT26. Temps however, were very stable, 800-900 degress (F) max pushing it as hard as it would go. I couldn't see any smoke behind me.

For now, I'm hunting to try and eliminate the cold idle smoke. I turned the MBC down to compensate for the extra boost (idea is no more than 15psi max) and rotated the aneroid pin back a more conservative profile. My "hope" is that the pin (at idle) is resting on the widest part of the aneroid pin which has zero contour/grinding to it. If it's got less smoke at idle, I'll gradually turn the main fuel screw down and increase boost via the MBC.

Spec: 96' 1HD-FT, rebuilt IP, brand new OEM injectors, H151, rebuilt CT26, 3" inside the frame rail exhaust

I'm frankly happy with the performance/power at this point given the fact that I don't have an intercooler or larger turbo. It's plenty quick enough. Just less cold idle smoke please....

 

[Workhorse]

Steve or Ross, any updates with your mods? Impressions so far? Have you made tweeks to them?


Also, bump this to the top again!!!

Ross

 

[loucaojr]

I am happy with the new cap, it has good off boost adjustment and looks bling The ...

View attachment 1612354

HI!!

Quick one, Will this cap fit on my 1HD-T?

Cheers

 

[loucaojr]

HI!!

Quick one, Will this cap fit on my 1HD-T?

Cheers

Anyone?!

 

[ForealBoreal]

Yes it should.
The denso and the Bosch lids are interchangeable. It should work just fine