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DEV - Injection Pump Tuning Guide

Discussion in 'Diesel Tech / 24 volts' started by diby 2000, Apr 21, 2017.

  1. diby 2000

    diby 2000

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    This thread is not intended to replace the Official tuning thread but rather I would like some feedback on my understanding and procedure before I post in there.

    A little bit of background info. I have an 80 series 1HD-FT with the A442F Automatic transmission with 333,333 klms on the clock. I have previously tuned the pump and boost compensator with good results but now I have a new turbo on its way and I thought this was a good time to put some of my thoughts and understanding down in words before I embark on the tuning when the new turbo is on. With all the reading I have done with regards to tuning I have not seen a written step by step tuning procedure until recently.
    I plan to start tuning from step one and my intention is to get the best tune for my setup. My perception of the best tune may be different to others but I want a clean, safe tune with optimal boost response without smoke.
    I have on board boost (both pre and post intercooler) pre turbo EGT and AFR gauges plus the ability to measure pre and post intercooler temperatures and exhaust manifold pressure.

    Anyway, the next post will contain a tuning procedure that I have not yet used. I say again this is a theoretical procedure at this stage. I would like some feedback and thoughts from the wise folk here before my new turbo is installed and I begin tuning.
     
  2. diby 2000

    diby 2000

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    Start Tuning

    1. Find max boost target - The maximum fuel volume the injector pump and injectors can deliver may limit the maximum boost level target. To find this boost target ensure that the follower pin will travel to its maximum extension of the aneroid taper used and not travel up the over boost portion on the taper. For this step, I plan to remove the spring from beneath the diaphragm and add spacers between the pump body and the bottom of the diaphragm to limit the aneroid travel into the pump to ensure the follower pin cannot ride up the over boost taper. The aneroid taper used and spring tension is not critical at this point as long as the follower pin reaches its maximum extension as we are only finding the max boost target. The no boost and spooling fuel levels may be richer than desired at full throttle but we can control that with our foot for now. Set the boost controller to the desired boost level and set the maximum fuel screw position to a full boost, full load AFR (22:1). If the AFR target cannot be achieved and is lean, (>22:1) the injection pump/injector combo may not be able to deliver the fuel required so while leaving the max fuel screw at the maximum position, begin winding the boost back until the full boost, full load AFR is at the desired position. This boost level becomes the maximum boost target.


    2. Find the boost level required to transition from spooling fuel levels to full fuel level - Once step 1 is achieved, slowly wind the boost back without touching the max fuel screw until your spooling fuel AFR (18:1) is reached. This becomes the boost level where the aneroid should stop traveling into the pump and therefore the boost level where the follower pin stops extending out of the pump. After the turbo reaches this boost level, the fueling per psi should remain the same and the extra boost is used to lean the AFRs to full boost, full load levels (22:1).
    Note - Another option for tuning is to have a flat section on the aneroid taper at the max fuel position and allow the aneroid to continue traveling into the pump without the follower pin extending any further out of the pump. I see a few negatives to this method: 1. The max spooling rpm still has to be found and the flat section will have to be ground to this point. 2. This method effectively reduces the taper vs. boost resolution as the same taper distance is now used for a greater boost value. 3. Because of 2. the spring preload will have to be increased meaning there will be more boost required before the taper will begin to travel into the pump which reduces the no to low boost tuning ability of the compensator. Due to these reasons I will pursue the first method and ignore the second from here on.


    3. Find the maximum depth of the aneroid taper grind required to lean out the no boost fuel level - If after the max fuel is set in step 1, reinstall the spring beneath the diaphragm and test the no boost full throttle fuel level AFR. If this is found to be too lean (I'm plan to aim for <14:1 >16:1 with a performance turbo) ensure the spring seat star wheel is adjusted high enough that the start position of the aneroid is dictated by the smoke screw cam and then adjust the smoke screw to force the aneroid start position to deeper into the pump. This means the follower pin starts on the aneroid taper and not on the outer diameter of the aneroid. If the no boost fuel AFR is too rich adjust the smoke screw to allow the follower pin to ride higher toward the maximum aneroid taper diameter. I would like to keep the smoke screw adjustment if possible at this point. This may be a futile effort and may not be possible or required in the end, and I may have to grind the top of the aneroid and the profile from the smoke screw cam but I will cross that bridge if I find the no boost fuel is still too rich and the follower pin is still not riding on the aneroid outer diameter. To allow the aneroid to extend further up out of the pump I plan to insert a thick gasket under the top diaphragm cap. If after allowing the follower pin to start on the outer diameter of the aneroid the no boost fuel is still too rich, to increase the difference in the no boost fuel delivery to full boost fuel delivery the follower pin has to travel further from one (no boost) to the other (full boost). As we now have the follower pin starting at the aneroid maximum diameter the only change we can make now is to grind a deeper depth on the taper and set the full boost fuel again. I remember reading somewhere that the pin follower only extends so far out of the pump (6.2mm or 6.5mm I will have to confirm) so a grind any deeper than this is useless. To find the maximum distance the aneroid can travel into the pump I plan to use the follower pin to measure the distance that the aneroid can travel by removing the diaphragm from the aneroid and adding a spacer between the bottom of the diaphragm and the top of the pin to allow maximum travel before the diaphragm bottoms out on the pump body and rotating the aneroid once it is at max depth. The follower pin will then mark the end point for the maximum aneroid taper. Once this measurement is known I will then grind a deeper section of taper to this section and set up the full fuel to this point as per set 1. From my reading I expect that even when the follower pin rides from the outer aneroid diameter to the maximum aneroid taper depth, the no boost fuel may still be richer than desired. The is nothing else we can do about this without pump modifications.


    4. Find the spring preload required to allow the aneroid to travel the correct distance into the pump - The spring preload (the force already applied to the spring when the aneroid is at its starting position) and or spring free length (height of the uncompressed spring can be made longer by adding spacers) are the only adjustments we can make to this setup as the spring rate (distance the spring will compress as more pressure is applied) is set and short of replacing the spring there is nothing we can do about this. This means that we can only really adjust the preload (force required to be applied by the diaphragm before the aneroid will begin to move down into the pump) to limit how far the aneroid will travel into the pump at the desired pressure. This can be done by making a controlled pressure test rig to simulate boost pressure onto the top of the diaphragm. Start by removing the aneroid from the pump and the coloring the taper where the follower pin will ride with a permanent marker and then reinstalling the aneroid. At this point you simulate the maximum spooling boost level found in step 2 (not full boost) a few times with the test rig. This will show where the follower pin is riding on the aneroid taper. The spring seat star wheel will need to be adjusted up or down to allow the follower pin to ride along the whole taper. It is best to test that the follower is not traveling the whole taper to early by performing the same test with a slightly lower pressure and ensuring the follower pin does not travel the whole way up the taper. Ideally a new stiffer spring will provide the best solution here but I will proceed with the stock spring for now. Due to the stock spring being a bit soft, this setup is going to be a compromise between spring preload and aneroid travel. As the aneroid travel is more important this will be the deciding factor for me.


    5. Customize aneroid taper profile for best turbo response - Now that the maximum boost is set, the maximum fuel is set, the no boost maximum fuel is set and the aneroid travel is optimized to the maximum spooling boost level, we can begin customizing the aneroid taper to provide the optimal fueling levels to assist in making the turbo as responsive as possible. My intended method to achieve this will be a slow process but I intend to find the best taper possible for my turbo. My plan is to lower the boost controller pressure one psi at a time and grind the taper to suit maximum spooling AFR. For example if my maximum spooling pressure found in step 2 is 25spi (@18:1 AFR), reduce the boost controller to supply 24psi and drive to full load, full boost and note the AFR. If the AFR at this point is leaner than my spooling AFR of 18:1 I will grind a little bit from the taper at the 24spi mark and test again until the AFR at 24psi is at 18:1. Once this is right I will reduce the boost controller to 23psi and repeat the process again. Once I have reached a point that the boost controller is not controlling the boost at all because the delivered pressure is purely controlled by waste gate spring tension alone, I will try my best to load up the turbo at low rpm and note the AFR and boost pressure and grind from there. This will not be as accurate as the previous method but I cannot think of a another way to do this. I plan on watching the AFR and boost levels and slowly grind from the higher boost portion until I see the AFR reaching the spooling set point. Depending on the no to low boost turbo response, the no boost AFRs and the boost pressure required to overcome the spring preload I expect to maintain slightly higher AFRs until the turbo is delivering a few psi of boost.

    The other factor here that is unknown to me at this stage is the possible benefits to running a slightly deeper grind on the taper for spooling (resulting in a richer AFR than the setup described above) as the turbo may be able to build boost faster than the compensator can adjust for the extra boost. The benefit of this may be an even more responsive turbo still without a sooty exhaust. I will cross this bridge after I have finished all the steps above.
     
  3. ForealBoreal

    ForealBoreal 1HZ Boostin

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    adding to the other thread.
     
  4. diby 2000

    diby 2000

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    @ForealBoreal Did you add it to the official thread because that's where I should have posted it or because you like the procedure?
     
  5. mudgudgeon

    mudgudgeon

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    Dolby, I think keep this separate so you can log progress on this project. I'm very interested on following this separately from the "official" thread.

    Good write up. I'll have to have a better read after coffee kicks in a bit more

    I have an IP apart on my bench at the moment.
    I think there's a lot of room for improvement in adjusting the aneroid function by optimising the settings and position of all the different elements, and also in optimising the pin profile.

    I'm thinking a concaved pin profile that rapidly increases fueling as boost initially builds could help achieve max boost quicker.

    There's a lot of room for adjustment to allow the pin to travel as long a distance as possible.
    I'm also thinking the pin profile grind can be maximised to get as much travel from the follower pin, and the lever arm the follower pin acts on as possible.
     
  6. mudgudgeon

    mudgudgeon

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    I have a ZEXEL VE pump I'm going to cannibalize for the boost compensator components to go on my 1HZ turbo project.

    I'll be modifying some of the parts as I put it together to try and maximise the function of the aneroid

    If you want pics, or measurements of any parts, let me know.
     
  7. diby 2000

    diby 2000

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    Thanks mate.

    I was thinking to keep this separate until I had at least used this procedure myself and proven it before posting it in the official tuning thread.

    I was planning on doing some (or stealing) rough sketches of pin profiles and how I think they may work. I have differing thoughts on what the taper profile will look like every time I think about it. That is the reason for my last paragraph really.
    Theoretically the taper should be a constant ramp that maintains the same fuel increase for boost increase but like you say a concave ramp may work better as the pump/compensator response to the boost may not be quick enough. I'm guessing the turbos boost response to drive energy will be rather quick once it is making the first ??? of psi. That will mean the transition from slight boost to full boost could happen very quickly.
     
  8. diby 2000

    diby 2000

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    I would be interested to know if the follower pin travel could possibly be increased to increase the difference between no boost fuel and full boost fuel?
     
  9. mudgudgeon

    mudgudgeon

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    Yes, I think it can.
    I started looking at this the other night.

    Give me some time, I'll get some measurements of the maximum possible range of movement for the follower pin, and the lever it acts on.
     
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  10. mudgudgeon

    mudgudgeon

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    Ok, heres a couple of pics and dimensions

    IMG_20170417_185830.jpg

    pic of the threaded sleeve for the aneroid pin in place in the boost compensator housing

    IMG_20170422_132558.jpg

    pic of the aneroid pin and diaphragm, the star wheel and detent spring, and the threaded sleeve out of the housing, and the follower pin and control lever.

    the control lever pushes against the fuel governor lever and spring in the main pump body

    IMG_20170422_132620.jpg

    boost compensator housing with threaded sleeve removed
     

    Attached Files:

    Last edited: Apr 21, 2017
    jpsfj60 and diby 2000 like this.
  11. mudgudgeon

    mudgudgeon

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    Hmmm, I was hoping the PDFs would come up as images, not links.

    Ive put some dimensions on the cutaway diagram showing max possible travel of the aneroid pin, and the follower pin/lever.
     
  12. mudgudgeon

    mudgudgeon

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    I will be looking at adjusting the position of the threaded sleeve so it allows the aneroid pin to just bottom out in the housing. (Sleeve may need modification)

    I will also look at shimming the top cover and diaphragm up from the main body so when the aneroid pin is in the "off boost" position, the full diameter portion at the bottom of the pin is resting ~2-3mm below the follower pin, and can travel the max distance of ~17mm into the housing.

    pin taper can be up to 4mm from full diameter to maximum eccentricity in the grind. more than 4mm is pointless as the lever will contact the housing.

    after that, the usual spring preload, aneroid pin position, off boost screw, and fuel screw adjustments all come into play
     
  13. diby 2000

    diby 2000

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    Thanks @mudgudgeon

    That's all brilliant info.
    I have to say 4mm for follower pin isn't much. Taper grind is going to be fine!
     
  14. mudgudgeon

    mudgudgeon

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    no worries, hope it helps.

    4mm doesn't seem like a lot, but in the scheme of whats happening in the pump, its a fair bit.

    the pin in my picture has about 3mm taper, and very little eccentricity
     
  15. ForealBoreal

    ForealBoreal 1HZ Boostin

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    @diby 2000 figured we could complied it to one main thread.
    Yeah the procedure is good.