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I've been following the cackle threads since December. I've done the Tank and pre-pump mods and have all the stuff for the regulator mod. Just waiting for the time to do them. As you know if you have been following along, cackle is related to the 6-8 firing of the injectors too close to one another in time and proximity. There has been some talk of the , split shot releated robbing or adding to much to the fill of #8, enough pressure in the fuel rail, fuel flow, a harmonic wave etc etc. I was toying with the idea of a modified Fuel Rail Drain Plug to have more of a direct effect. Havent seen anybody mention the idea. I wanted to see what everybody thought of doing something like that and what ideas you may have. I was thinking of maybee an accumulator right off the drain (drivers side rear) or a variable length hose type deal to tune in the right volume or pressure spike rebound to make this PSD run right. I've been prompted to this by the posts of everybody who had done all mods and still have a knock. I have a machine shop pretty much at my disposal. If I do find something that works I will post a detailed dimensional drawing (I've worked a mechanical design engineer and draftsman in my time). Also looking for the International part number for the drain plug and o-ring so I can order one to work from. Any thoughts or comments? And as always, Thanks to everybody who has worked so hard to find the solution. Ray |
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Ray, I think Hutch had drawn up a cone looking affair at some point to do just what you are proposing. I will try to find his drawing. Maybe he will chime in here after awhile. Rob |
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DieselRay, In reply to:  Now your talking my language Hutch and I talked about this back in February of this year and you may want to review the following Posts which have some thoughts on what your looking at: 3/1/02 Post 3/2/02 Post 5/9/02 Post 5/10/02 Post 5/12/02 Post I personally would like to actually block( with either some shock absorbing material or spring blocker attached to the drain plug) the fuel rail between #6 and #8. Dead end feed 2,4,6 and the passenger side using the factory system and feed #8 (maybe with an accumulitaor) thru the drain plug and maybe use an orfice to return this fuel chamber via the rear driver's side fuel test port. This third supply might require a second fuel pump.  Larry |
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I don't think harmonics are playing too big a role in the fuel rails, the absence of fuel flow is the negative issue with the factory fuel system. I have always been sure and I am still convinced they are VERY TROUBLESOME surge harmonic/resonance issues in the HP oil rails and injectors. I still think the injectors cannot dump all the HP oil during very high HP oil rail and long duration injection cycles (high load on engine) plus I still do not think the equilization circuit for the popett is large enough to ensure the poppet valve will seat properly during these "high load" injection cycles. |
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Larry: KL tried separating the fuel rail between 6 & 8 and found that this was not the answer. This also suggests that flow alone is not the problem, nor necessarily the harmonic interaction to #8. Sorry to pose more questions than answers. Pat |
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Pat, In reply to: I remember seeing this being talked about HERE and HERE, but after THIS things seems to have gone underground.  I must have missed where the results of all these not working were posted. Can you point me to where I can find where this didn't work and exactly what was done. Also, I do find interesting the timing between what was going on in the two/three weeks prior to the third link above. Also recent posts such as THIS and my investigations still IMHO leave this an an open issue at least for me.I also have repeatedly stated that harmonics IMHO is only one potential problem. Simply installing a dispersion/absorption device will not address the effect of the direct shockwave from whatever source along with it's potential source as a air releasing phenomenon, #6 seems to be the selected source, but I haven't ruled out say either a direct or first reflect pressure/shockwave(from the front or back of the fuel rail) from either #2,4 or 6. Again, a dispersion/absorption on the back of the fuel rail won't have an effect on the direct or front reflected sources from #2,4, or 6. Finally, like Hutch I have never eliminated significant problems in the HP oil side contributing or actually being the or at least one of thes causes of the problem. I just haven't seen the data yet. Thanks, Larry |
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Interesting reading. Thanks guys. I knew you'd be in Larry  . I'm trying to take as logical of an approach as possible. I think what I'm going to do is install the regulator then experiment with some type of dampening device on the LH fuel rail drain plug port. I think the last part of the puzzle may be the shock wave dispersion of the fuel rail. My thought is that the ball valve before the spill port in the injector is hopping off its seat by the shock waves in the rail. Either that or something similar. I don't know for sure and I'm no expert. At any rate, its worth a shot but only after the other mods have been done. In my own experience just changing my dirty fuel filter got rid of most of the cackle my truck was experiencing. The tank mods only improved my truck for a much more responsive throttle with more power and improved MPG (1 mpg to be exact). Now I'm looking ahead to the next steps to take. Ray |
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DieselRay, In reply to: HERE is another one I missed that muses on this direct, reflected, harmonic situation and why IMHO TT's regulator mod might be working as discussed at the very end of the post which points to a one explanable instance of the actual cause of cackle and a reason a certain mod corrected it. Don't forget it could be a random combination plus PCM,IDM,ICP,etc. variances.
Larry Edited by Larry M (06/11/02 06:26 PM) |
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Well the wheels in my head are definately turning. Or was that spinning  I've fallen behind a bit in whats goin on. Too much info and too little time. I didnt even see the single circuit "mod to the mod", so to speak, until today. That plug looks easy to duplicate. To hard to pass up trying a little frankenstein mod Thanks again. Ray |
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Changing Harmonics of the Fuel Rail
Re: Changing Harmonics of the Fuel Rail
