Mine went to 11.0 stock.
The Official 1HD-T/FT Fuel Pump Mod Tuning Thread (8 Viewers)
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Mine went to 11.0 stock.
Mine was 10.5 at best stock.
Mine is an FT it that makes a difference though I don't think so.
Mine was 10-11psi stock as well, wouldn't go above that no matter the engine load.
Hmmm, interesting.
I guess when I say mine was stock, I don't know what was done with it before I had it. Mine was a grey import HDJ81, and some things had definitely been tweaked. thinking about it, I think my IP had no seal on the main fuel screw
I guess when I say mine was stock, I don't know what was done with it before I had it. Mine was a grey import HDJ81, and some things had definitely been tweaked. thinking about it, I think my IP had no seal on the main fuel screw
So, I decided to increase preload on the boost compensator spring today... and while I was at it, increase boost a few psi. I did that and the fueling "ramp" if you will was improved but my EGTs went up across the board. Just to be sure it wasn't boost related, I adjusted the boost back to where it was... still high EGTs. So, now I'm wondering if my main fuel screw is too open. Since, it seems like I'm running high EGTs across the entire RPM range and I'm getting a big puff of smoke if I stab the throttle in park. What do you guys think? I'd like to get this thing properly adjusted and be done with it...
@mudgudgeon
@mudgudgeon
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Also, if you guys say that I do need to adjust the main fuel screw to reduce fueling across the board... Is this the screw in the center of this pic?
yep, that is the main fuel screw. So changing preload made an improvement to performance?
if so, then yeah, try changing the main fuel screw a little. Start with 1/16, 1/8 of a turn. If you have the tuning close, you may not need to change the main fuel screw much at all.
Or leave the main fuel screw as is, and put preload back to what it was. Its a balancing act
if so, then yeah, try changing the main fuel screw a little. Start with 1/16, 1/8 of a turn. If you have the tuning close, you may not need to change the main fuel screw much at all.
Or leave the main fuel screw as is, and put preload back to what it was. Its a balancing act
Yeah, so what happened before was that at 3/4 throttle EGTs would climb to 1100 F on the long hill. But at full throttle, they would drop back down. From that, I guessed that I still was hitting fuel cutoff. So, I increased preload on the boost compensator a bit. This made performance, and EGTs climb quicker and, now, EGTs climb faster at full throttle than 3/4. Right now, I can climb up past 1300, if I stay in it. If I stay at 3/4 throttle, EGTs will climb to around 1100. It seems like the truck is running hot across the board. I backed the main screw off aobut 1/16th of a turn... still hot. Maybe better but still hot. Maybe I'll try backing it out a little more tomorrow. Just to be sure, I should be turning counter clockwise to reduce fuel, right?
Thanks for the help,
yes counter clockwise to reduce fuel. On the 'long hill' is the trans in lock up, lower revs (under 2000rpm) and not much boost? if so try switching off the overdrive button on the shifter, and put it back on when your over the top of the hill. EGT's will go up if its labouring with the auto in O/D at lower revs
On the the hill revs are 2200ish with trans locked up. But when I press the gas and down shift, the temps keep climbing.
@Lumpskie I'm in the same boat as you right now. My boost compensator is working correctly so now I am fine tuning with the fuel screw. Remember that you can also rotate your diaphragm (as long as you don't have a custom grind on your rod) and that will change your mid-high boost fueling as well.
My current methodology is to set the main fuel screw to get the off the line performance I want, then take fuel out of top end by rotating the diaphragm to a more shallow cut. I have it dialed in "close enough" considering I have a exhaust and inter-cooler going on in the not so distant future.
My current methodology is to set the main fuel screw to get the off the line performance I want, then take fuel out of top end by rotating the diaphragm to a more shallow cut. I have it dialed in "close enough" considering I have a exhaust and inter-cooler going on in the not so distant future.
I'm going to drop this here.
Its one peice of info I found about 10yrs ago and found it really helpful in understanding the VE pump and boost compensator.
its written for tuning a landrover VE pump, there is minor differences to toyota/Denso VE pump but gives some useful info.
Its one peice of info I found about 10yrs ago and found it really helpful in understanding the VE pump and boost compensator.
its written for tuning a landrover VE pump, there is minor differences to toyota/Denso VE pump but gives some useful info.
Reading now...
Ok, you guys... I believe I'm getting too much fuel across the board. Today, I am going to rotate my aneroid rod back to the minimum fueling position. If that doesn't work (I don't hold much hope), should I reduce fuel with the main fuel screw? Or should I just adjust the boost compensator back to where it was? I believe that it was running into fuel cutoff... just slightly. But, overall the vehicle drove pretty good. On the other hand, it wasn't truely "right" because when in 4th, with torque converter locked out, at 2000ish RPMs, I could push the gas peddle to 75% and get EGTs to really climb. I was hoping to get this rig tuned so that, under no circumstance, would I exceed 1100 degrees F...
If rotating your fuel pin to a less aggressive profile doesn't get you where you want to go, then I'd turn down the main fuel screw a bit and see how that goes.
Lugging the engine will cause EGT's to rise, so trying to pull a hill in 4th w/ TC locked up would bring those conditions. Maybe worth playing with the trans kickdown cable some more so it downshifts earlier in those conditions? Or manually downshift and see if it improves 1st?
Lugging the engine will cause EGT's to rise, so trying to pull a hill in 4th w/ TC locked up would bring those conditions. Maybe worth playing with the trans kickdown cable some more so it downshifts earlier in those conditions? Or manually downshift and see if it improves 1st?
Thanks for the advice, @IanB . I'll do that. (rotate pin and test... then turn down fuel screw if I need to cool EGTs further) Thanks for the advice about the kickdown cable too. That made a big difference and I think I have that pretty dialed in at this point.
I agree with Ian.
Just try and change only one thing at a time, then test or it becomes very easy to lose track of what you've done.
I tinkered with mine regularly for months trying to get it running at its best (partly because there was f-all info available).
Tweaking and fine tuning and testing yourself could take quite some time.
I had a good steep hill near me I drove every day to get to work. It was perfect for testing after a tweak, I could do a WOT run and load it up and check peak EGTs straight away.
Just try and change only one thing at a time, then test or it becomes very easy to lose track of what you've done.
I tinkered with mine regularly for months trying to get it running at its best (partly because there was f-all info available).
Tweaking and fine tuning and testing yourself could take quite some time.
I had a good steep hill near me I drove every day to get to work. It was perfect for testing after a tweak, I could do a WOT run and load it up and check peak EGTs straight away.
Where I live, the only significant hills are found in the river valleys...for HOURS in any direction. Even then, it's a hill, not a mountain, you can't keep the engine loaded up for more than 20 sec at a time, very different than the terrain out west. It's cheaper and quicker to pay for dyno time.
chapel gate
GOLD Star
Is it my eyes or is the anti tamper sleeve still on the main fuel screw?Also, if you guys say that I do need to adjust the main fuel screw to reduce fueling across the board... Is this the screw in the center of this pic?
