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Wastegate Questions; any old threads?


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I'll look again tomorrow when I am fresh and let you know; I am sure it goes up some, but I have too many configs in my head now so am not sure.

When the truck is shut off, the pressure spikes up for about 4 to 5 seconds, plateaus and then slowly drops to about 3 or 4 psi and this takes at most 10 to 15 seconds (I believe). Again, will confirm in the morning.

My fuel gauge setup starts off with an 1/8" tap into the banjo fitting as described. However, I used an 1/8 female npt to 1/4" barb, 1/4 inch hose about 4 ft long (so I can hold gauge in cab of truck), needle valve and gauge together. Assuming I got the air out (simply turned key on until electric fuel pump pushed fuel out the end of line while holding line up), it should be a closed hydraulic system and so not care about step up in size of line (1/8" npt to 1/4"). Might be more steady with needle valve at other end of the line with 4' of diesel filled hose adding to dampening?

Many thanks

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Mine are:

0402 736 841

PES6P120A120RS7275

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Great info. Thx. Confirms mine is a manual pump for a 1995, 175 hp.

--- Update to the previous post...

The plot thickens. I decided to go ahead and set the timing to 14.5 BTDC which I did. Tried starting the truck and it wouldn't run for crap and put out copious quantities of white smoke. Assumed the gear had slipped, so rechecked and timing spot on at where I had set it which is actually about 14 to 14. 25 BTDC or .178 inches of lift.

Process: Bring engine to approx TDC based on marks on harmonic pulley and both valves closed (loose in and ex rockers) on #1 cylinder, install dial indicator with about .3" preset, back engine until dial clearly has stopped moving, zero dial indicator, and turn harmonic pulley forward until pin drops into hole and read gauge .178"

Assuming I have not done something stupid, something is up. Any thoughts? Thank you

--- Update to the previous post...

Darn am I dumb; I had it at 14.5 BTDC all along and just changed it to something off the chart by pulling info from the wrong column; should have been a lift of .244 for 15 or .240 for 14.5; I had .240.

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What marks on the pulley are you talking about? The intake and exhaust are closed on #1 for a long time, a degree is like 1/16th of an inch and the duration they are both closed is several inches. Here is how to find true TDC. http://forum.mopar1973man.com/threads/3758-Finding-Absolute-TDC Just remember to do it EXACTLY as it says, I don't care how stupid you might look for checking the procedure 10 times before doing each step, one mistake can cost thousands. I also don't recommend doing this if you don't have a way to tediously bar the engine. You use the engine barring tool from cummins to do it. You need to be able to go forwards and backwards anyways so the alternator won't allow that. I am not gonna be able to do the fuel pressure thing today so maybe Sunday.

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the marks are painted on as approximate and I use them and the valve position only to get close to TDC ; again, using the dowel to get TDC. Reset timing at 15, 15.25 BTDC (it was 14.5 BTDC before I messed with it). For some reason I don't get, not I am getting consistent 30 PSI on my gauge with needle valve just cracked open. I truly do not get this as I haven't changed anything else at all. I guess I'll put the fuel lines back on the way they were and drive it and see where I am so to speak.

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Alright now I see where your coming from. I even put a needle valve at the pump and at the gauge in the cab, so there's 2. If you almost sinch it off it starts reading high pressures but that is so tight that it is just holding the peak pressures. It needs to be a little lower (some needle movement). I know it is bad for the gauge but that's just the way it has to be. These lift pumps pump too slowly to work like a 24V. If you watch Mike's vids on his 24V you can see his needle goes insane but I can leave my needle valve loose and the needle on the gauge just vibrates but isn't exactly insane. This means he can do it a lot easier than we can. I also noticed the overflow valve doing it's thing. You can get to about 35psi and then watch it fall to 25 then build back up. On a downhill left in gear coasting I can hit 43psi or so, I take it that is only because there is no fuel being used and the overflow is jamming out as much as it can but it's still not enough to regulate the pressure so it spikes to above 40.

I have it semi-permanent in my truck, last time I did just a quick run and that's all I did this time as well. I am going to play with it all week and see what it does. I wasn't able to get under 30psi at WOT but I am not sure if the needle valve was too tight so I will continue messing with it and eventually get some video.

I drew a picture showing the differences. The center line is what the gauge is doing with the perfect needle valve setting with the other lines being the pressure pulsations of the lift pump. It shows that even with it perfect, there is just too much time in between pulsations on the ppump lift pump to show a solid gauge needle, it will go up and down. This is idle speed.. As RPM goes up, it becomes possible to get the thing to stay solid, in theory, need to see if it works out through the week. The 24V pump is electric, so it's basically like we were doing 3000RPM continuously (maybe faster) so they have no problem with time between pulsations and are able to get the gauge to hold steady.

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