Here are a couple vids on you tube dealing with the android pin and boost comp spring setting. You'll see in the second video he uses paint pen on the fuel pin to show the travel of the follower pin
The Official 1HD-T/FT Fuel Pump Mod Tuning Thread
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[/QUOTE][/QUOTE]Too late, it was heavily modified (with no indication of where stock was) when I brought the truck over from Japan. I have zero idea where the "stock" setting is on the main fuel screw.
How do I do that? Put paint pen on the pin?
I already have it running on the cut section. I didn't even try the stock.
Yes, there were 2 small washer like spacers that were there. One fatter one and one really skinny one.
Mostly. Not certain about the spring tension. Another thing I have noticed since putting the new pin in, is that my boost doesn't build as quickly. I'm thinking my other pin was just far, far more aggressive, resulting in way more fuel. Which means I may need to turn the main fuel screw up?
I figured that with the fuel screw.
You can use a light coating of white lithium grease... You'll be able to see.
All those washers do is prevent the pin from traveling deeper. They are stops essentially. They can be used in the tuning process if you need to raise your AFRs
The spring tension takes a bit of playing with. The gauge thing would probably work well.
Remember turning the star wheel counter clockwise you are increasing the spring tension and it would be the opposite turning it into the housing (less spring tension)
The pin will index differently depending where you have you're star wheel also.
Most people have a really good idea of tuning after screwing the the boost comp and setting it up to your driving style/AFR/EGT level.
Good luck this will make sense at some point here.
asutherland
VA7 HDT
Thanks, after watching that second video the spring tension makes more sense. If you alter your boost, you need to ensure the spring has enough tension to keep it from riding up into fuel cut out.. or the alternate, if the spring is under too much tension for the boost you have, it will not rid up far enough.
I'm going to try the bike pump trick after I take a look at my pin again. The part I don't get is, because the pin is currently installed with the (cut), more aggressive angle, and the adjustment screw is set to max... why would it behave so gutless compared to my old pin? Are they really that different? If that's the case, I assume the main fuel screw is my next thing to adjust, correct? (it's already been molested, so I have no problems adjusting it and testing)
Side note... the 2 small washers/spacers, should I remove them?
thx again
Andrew
I'm going to try the bike pump trick after I take a look at my pin again. The part I don't get is, because the pin is currently installed with the (cut), more aggressive angle, and the adjustment screw is set to max... why would it behave so gutless compared to my old pin? Are they really that different? If that's the case, I assume the main fuel screw is my next thing to adjust, correct? (it's already been molested, so I have no problems adjusting it and testing)
Side note... the 2 small washers/spacers, should I remove them?
thx again
Andrew
mudgudgeon
Resident galah
I would guess comparing the worn groove and your new rod profile, the follower pin will be in a significantly different position. I would hazard a guess that your new pin has reduced fuel available were you need it most for throttle response
The purpose of the boost compensator is to allow a richer setting on the main fuel screw (more fuel available under all conditions). The aneroid pin then reduces the fuel available when it's not needed ie, at idle, at cruise with very little throttle and low boost .
The boost compensator gives a large range of tune-ability and improves economy.
You need to consider
-Main fuel screw setting - adjusts fuel available at every other setting and max fuel
-off boost fuel settings. (Top of boost comp) allows you to tune for throttle response from a standing start
-spring pre-load (star wheel) - more spring preload delays the point at which aneroid rod will be shifted. More boost will be required to over come spring preload.
-orientation of the aneroid rod - the factory rod was ground eccentrically, rotating the rod changed the profile the follower pin would follow and therefore changed response.
(Sorry for clumsy explanation, it's a while since I fiddled with one of these)
All settings react and interact with all other settings. To an extent, it's a dark art tuning them. Takes a fair amount of trial and error to get a good grasp on what does what.
Given you have no clue what your starting point is due to PO's mods you have nothing to lose by tinkering.
Keep an eye on EGTS, AFRs (if you can get hold of a gauge) and peak boost.
Peak boost will change as you adjust fuel settings. If you have stock wastegate it probably doesn't matter much, if you have a boost controller, it's something to watch
The purpose of the boost compensator is to allow a richer setting on the main fuel screw (more fuel available under all conditions). The aneroid pin then reduces the fuel available when it's not needed ie, at idle, at cruise with very little throttle and low boost .
The boost compensator gives a large range of tune-ability and improves economy.
You need to consider
-Main fuel screw setting - adjusts fuel available at every other setting and max fuel
-off boost fuel settings. (Top of boost comp) allows you to tune for throttle response from a standing start
-spring pre-load (star wheel) - more spring preload delays the point at which aneroid rod will be shifted. More boost will be required to over come spring preload.
-orientation of the aneroid rod - the factory rod was ground eccentrically, rotating the rod changed the profile the follower pin would follow and therefore changed response.
(Sorry for clumsy explanation, it's a while since I fiddled with one of these)
All settings react and interact with all other settings. To an extent, it's a dark art tuning them. Takes a fair amount of trial and error to get a good grasp on what does what.
Given you have no clue what your starting point is due to PO's mods you have nothing to lose by tinkering.
Keep an eye on EGTS, AFRs (if you can get hold of a gauge) and peak boost.
Peak boost will change as you adjust fuel settings. If you have stock wastegate it probably doesn't matter much, if you have a boost controller, it's something to watch
asutherland
VA7 HDT
So I took the new pin out and laid it beside the aftermarket one. NO WONDER my "get going" low end is lacking!! Look at the difference... the aftermarket one I took out is 4mm longer, resulting in the guide pin on idle and low boost riding WAY higher on the full diameter of the (new) pin, instead of half way up the aftermarket one.
The last pic says it all! So, the end of the pin is your idle/low boost, and moving towards the threaded end is your high boost/rpm?
Edit: Weren't you complaining of a smoky idle at one point? Has that cleaned up with the stock pin?
Edit: Weren't you complaining of a smoky idle at one point? Has that cleaned up with the stock pin?
asutherland
VA7 HDT
Yep, and yep! Completely cleaned up. But I do need to figure out how to get it to come up a little faster. 5km to 35km takes like 10 seconds...
mudgudgeon
Resident galah
@asutherland , that last pic speaks volumes!
Is your new pin from Karter? If so, maybe that gives you a baseline.
The little follower pin is basically a valve. When the follower pin is low on the aneroid taper, the valve is reducing fuel flow. As the aneroid rod is pushed down and the taper is narrower, fuel flow increases.
Comparing those two rods, the worn rod is putting the follower pin at close to full flow, the new rod at the same depth from top has it close to minimum flow.
I think painting the new one, installing it , and applying 14psi to the aneroid as per the youtube vids will give you some idea what your starting with.
What's your setup?
What turbo do you have?
Intercooler?
Max EGTs?
Peak boost?
Exhaust?
The taper on the new aneroid rod looks too abrupt to my thinking.
I think it would be more suited to an aggressive turbo that builds boost quickly than a stock turbo. But I'm not certain of that
Is your new pin from Karter? If so, maybe that gives you a baseline.
The little follower pin is basically a valve. When the follower pin is low on the aneroid taper, the valve is reducing fuel flow. As the aneroid rod is pushed down and the taper is narrower, fuel flow increases.
Comparing those two rods, the worn rod is putting the follower pin at close to full flow, the new rod at the same depth from top has it close to minimum flow.
I think painting the new one, installing it , and applying 14psi to the aneroid as per the youtube vids will give you some idea what your starting with.
What's your setup?
What turbo do you have?
Intercooler?
Max EGTs?
Peak boost?
Exhaust?
The taper on the new aneroid rod looks too abrupt to my thinking.
I think it would be more suited to an aggressive turbo that builds boost quickly than a stock turbo. But I'm not certain of that
So, I'm real new to this pump tuning bit, but would stacking washers at the base of the pin, push the new pin out as though it were longer, putting you into the fueling part of the profile sooner? This would mimic the pin being longer like the 1st one you had?
Or is adjusting the spring pre-load via star wheel the proper way to go about addressing this?
Or is adjusting the spring pre-load via star wheel the proper way to go about addressing this?
asutherland
VA7 HDT
Yes it is.
Agreed. I did that last night, the follower pin appears to travel exactly 1cm from the full width of the pin (off boost, idle, at the bottom) into about 3/4 of the cut section. It's not so much the cut section I'm worried about, fuel up top and once I start to make boost above 5psi isn't really a problem... it's the GETTING to 5 psi that the truck is struggling with.
What's your setup?
What turbo do you have? - Stock turbo
Intercooler? - No
Max EGTs? - 1200 when pounding it up a hill (pre turbo)
Peak boost? - Manual adjustable, set to 14 psi currently
Exhaust? - 3 inch nice stainless
That wouldn't affect the initial "get up and go" fuel though would it? Just the top end?
asutherland
VA7 HDT
I have the same question. But, no room for washers above the diaphragm, and I think that's where they would have to be, no?
I've been thinking some more about this and have a couple thoughts/questions to better my understanding of how this works:
-how far the follower pin travels on the aneroid/s profile depends on the boost level? The boost compensator is the bit with the diaphram, and it acts on the boost level to push the aneroid pin in/out with the boost level?
-how does a non-turbo pump work in comparison? They still have an aneroid pin, correct? What controls how far the follower pin travels on the aneroid pin with no boost compensator?
asutherland
VA7 HDT
Yes, that's correct. Would also depend on the tension on the spring (adjusted by the star wheel).
Non boosted pump doesn't have a compensator as far as I know. Take a read through this, it really helped me understand... Mechanical Diesel Engine Tuning - No Chips! - Patrol 4x4 - Nissan Patrol Forum
Non boosted pump doesn't have a compensator as far as I know. Take a read through this, it really helped me understand... Mechanical Diesel Engine Tuning - No Chips! - Patrol 4x4 - Nissan Patrol Forum
That is a good read! So shims on the aneroid pin affect full boost fueling only, it's the no-boost fuel screw and star wheel adjustment you'll need to play with to get your off-boost fueling turned up to get your off the line performance back.
As for washers, it looks like they sandwich between the aneroid pin and the diaphram, so the pin is further into the pump at idle, moving the follower pin deeper into the pin's profile at idle/low boost operation.
On a pump with no boost compensator, you can really only play with the main fuel screw, and the aneroid pin profile for tuning, pretty limited in comparison.
mudgudgeon
Resident galah
You're both on the right track.
The off idle adjustment cam under the cover gives you your initial throttle response. Adjust it so the thickest part of the little cam plate is acting on the top of the aneroid rod. This pushes the rod down a little.
You want it so that with the truck stationary in neutral, jab the throttle hard for 1-2 seconds. You should get a puff of dark smoke initially, but it should clear quickly as the revs rise.
This should give adequate fuel for the truck to be responsive off the line. Ie, standing start, at idle, no boost, 1st gear, it should have enough torque to launch off the mark hard.
Then the star wheel spring preload comes into play.
If this setting is no good, your initial launch will fall flat. Boost will act on the spring progressively, so fuel delivery increases gradually, not in one hit.
Too much preload (effectively stiffens the spring) will delay fuel delivery until boost builds enough to overcome the preload. Fuel delivery can happen too late.
Not enough preload and increased fuel delivery will happen to soon and be all over before you gave your pants off.
Finding a happy medium is where the vodoo is
With EGTs at 1200F you still have a good safety margin for adding more fuel.
750C (1380F ?) is safe for sustained max temps, 800c (1450F ?) in short bursts is ok too, BUT definitely not as an extended max EGT.
(Mine typically ran to 750C, at times I would see 900C, but I wound fuel back so max spike would be around 800c. I ran it like this daily, 200km + daily, for 3yrs until I blew up a turbo and rebuilt the engine. Engine was pristine, nothing at all to indicate dangerous EGTs)
@asutherland I would first adjust the off idle cam, see what happens. (Probably not a lot)
I'd also increase main fuel setting. (Do it in tiny increments, it may only need 1/8th of a turn ).
I would adjust main fuel screw position before adding shims to the aneroid rod and diaphragm (if at all).
-Add fuel (main fuel screw)
-adjust idle screw (on the throttle arm) (mine idled happily as low as 650rpm which allowed a little more fuel and still good response)
-Check for puff of smoke when coming off idle (jab throttle hard, adjust off idle cam plate position if needed (most likely leave it on max),
-go for a drive.
-Find a big long hill and watch EGTs on a sustained full throttle run from around 1800 rpm through to red line.
Repeat as necessary.
Once you have it leaving the line ok, then fiddle with your star wheel position. This is all trial and error, and it's hard to keep track of what you've done and what effect your changes are having.
Keep an eye on EGTS and keep an eye on visible smoke as the engine comes off idle and builds boost and rpm as you accelerate. A little smoke on hard acceleration is ok, but you shouldn't be "rolling coal"
All the settings act together, a change at the star wheel might mean you take a little fuel out with the main screw, which then affects idle, off idle etc
Happy tinkering. Mine usually goes like this
The off idle adjustment cam under the cover gives you your initial throttle response. Adjust it so the thickest part of the little cam plate is acting on the top of the aneroid rod. This pushes the rod down a little.
You want it so that with the truck stationary in neutral, jab the throttle hard for 1-2 seconds. You should get a puff of dark smoke initially, but it should clear quickly as the revs rise.
This should give adequate fuel for the truck to be responsive off the line. Ie, standing start, at idle, no boost, 1st gear, it should have enough torque to launch off the mark hard.
Then the star wheel spring preload comes into play.
If this setting is no good, your initial launch will fall flat. Boost will act on the spring progressively, so fuel delivery increases gradually, not in one hit.
Too much preload (effectively stiffens the spring) will delay fuel delivery until boost builds enough to overcome the preload. Fuel delivery can happen too late.
Not enough preload and increased fuel delivery will happen to soon and be all over before you gave your pants off.
Finding a happy medium is where the vodoo is
With EGTs at 1200F you still have a good safety margin for adding more fuel.
750C (1380F ?) is safe for sustained max temps, 800c (1450F ?) in short bursts is ok too, BUT definitely not as an extended max EGT.
(Mine typically ran to 750C, at times I would see 900C, but I wound fuel back so max spike would be around 800c. I ran it like this daily, 200km + daily, for 3yrs until I blew up a turbo and rebuilt the engine. Engine was pristine, nothing at all to indicate dangerous EGTs)
@asutherland I would first adjust the off idle cam, see what happens. (Probably not a lot)
I'd also increase main fuel setting. (Do it in tiny increments, it may only need 1/8th of a turn ).
I would adjust main fuel screw position before adding shims to the aneroid rod and diaphragm (if at all).
-Add fuel (main fuel screw)
-adjust idle screw (on the throttle arm) (mine idled happily as low as 650rpm which allowed a little more fuel and still good response)
-Check for puff of smoke when coming off idle (jab throttle hard, adjust off idle cam plate position if needed (most likely leave it on max),
-go for a drive.
-Find a big long hill and watch EGTs on a sustained full throttle run from around 1800 rpm through to red line.
Repeat as necessary.
Once you have it leaving the line ok, then fiddle with your star wheel position. This is all trial and error, and it's hard to keep track of what you've done and what effect your changes are having.
Keep an eye on EGTS and keep an eye on visible smoke as the engine comes off idle and builds boost and rpm as you accelerate. A little smoke on hard acceleration is ok, but you shouldn't be "rolling coal"
All the settings act together, a change at the star wheel might mean you take a little fuel out with the main screw, which then affects idle, off idle etc
Happy tinkering. Mine usually goes like this
mudgudgeon
Resident galah
And yes, pumps on non-factory turbo models have no boost compensator.
You can adjust main fuel screw and idle screws only
You can adjust main fuel screw and idle screws only
asutherland
VA7 HDT
Thanks MG, what you said makes sense. I've upped the main fuel screw a bit and turned the compensator screw lobe down a bit. The truck is more drive able now, though I haven't hit a good highway hill to watch the egts yet. I did play with removing tension on the star wheel, but it resulted in smoke all the way through my range. Perhaps I turned the tension on the spring down too much. (3 full revs).
Next step is a long highway pull. I have a feeling the egts will be too high. Which means I suppose I will turn the main screw down a bit and maybe try lowering tension on the star wheel by say 1 full rev instead of 3.
What I was noticing most with the new pin was immediate off the line was ok, but then as I went into 2nd gear it would fall on its face until it got up to about 6psi and then pick up again.
Next step is a long highway pull. I have a feeling the egts will be too high. Which means I suppose I will turn the main screw down a bit and maybe try lowering tension on the star wheel by say 1 full rev instead of 3.
What I was noticing most with the new pin was immediate off the line was ok, but then as I went into 2nd gear it would fall on its face until it got up to about 6psi and then pick up again.
Did that improve when you tightened down the star wheel 3 turns (reducing spring preload)? That's what you would expect would help add fuel at lower boost levels, right?
I finally got a chance to watch these, everything is crystal clear now!
Non-turbo would have no boost compensator, so no aneroid pin at all, I was not getting that before.
How the boost compensator works is so much more clear now.
asutherland
VA7 HDT
Update on my tuning,
I've reached a tune that's pretty happy for me at the moment. When the weather gets hot it may need some adjusting. There's still some fine tuning to do, but the majority of it is working well now.
What I ended up doing to accommodate for the less aggressive afc pin was to turn the main fuel screw up about 1/4, turn down the compensator lobe screw to about 3/4, and lessen the spring tension by turning the "star wheel" in 3/4. I may be able to adjust things further by lessening the spring tension more and removing some of the main fuel, but we'll see.
Right now I have pretty consistent acceleration throughout the gears. It's no longer falling on it's face after shifting into 2nd, as it was doing before I adjusted the spring tension. I have max egt's of 1200 pre-turbo (if I'm trying hard) going up highway hills doing 120km/h in 4th gear w/lockup. ZERO smoke at idle and I cannot see ANY smoke while accelerating during the day... at night with car headlights there's just a touch of white coloured smoke, but I would say 10% of what I used to have!
I also am seeing better fuel economy - already. Since putting in the new pin I've added a good 4 days of daily driving (30km a day) to a tank, which is pretty significant!
No smoke and decent power and reasonable egt's make Andrew a happy boy
Thanks to everyone that helped me with this.
I've reached a tune that's pretty happy for me at the moment. When the weather gets hot it may need some adjusting. There's still some fine tuning to do, but the majority of it is working well now.
What I ended up doing to accommodate for the less aggressive afc pin was to turn the main fuel screw up about 1/4, turn down the compensator lobe screw to about 3/4, and lessen the spring tension by turning the "star wheel" in 3/4. I may be able to adjust things further by lessening the spring tension more and removing some of the main fuel, but we'll see.
Right now I have pretty consistent acceleration throughout the gears. It's no longer falling on it's face after shifting into 2nd, as it was doing before I adjusted the spring tension. I have max egt's of 1200 pre-turbo (if I'm trying hard) going up highway hills doing 120km/h in 4th gear w/lockup. ZERO smoke at idle and I cannot see ANY smoke while accelerating during the day... at night with car headlights there's just a touch of white coloured smoke, but I would say 10% of what I used to have!
I also am seeing better fuel economy - already. Since putting in the new pin I've added a good 4 days of daily driving (30km a day) to a tank, which is pretty significant!
No smoke and decent power and reasonable egt's make Andrew a happy boy
Thanks to everyone that helped me with this.
