Surging power 237

[Freightrain]

Well, a little update from my trip today.   Just got in, and not quite ready to lay down.

First, it ran like a TOP.  Perfect.  It actually has a bit more UMPH then it did.  I noticed about 1# more of boost(about 16) and it definitely has more pull on the hills it basically never lost speed on any hill and it used to as I made this trip last July.  It held 10# fuel pressure minimum, 1800 rpm, 16# boost, flat out in OD on a grade.  Like typically I usually think as long as it has fuel pressure remaining, then it can't use anymore anyway?

Now, I've done three things to it this past week.  I put 2 new filters on it(old, but still pretty clean inside).  Next I replaced the original fuel pump with the one off my 673.  It made the same 15# at idle and running down the road for the most part other then max load as I mentioned above.  I also filled the tanks before I left.  I had thoughts that maybe I have a draw tube issue(cracked) and if it gets down to 1/2 tank or just above it was drawing air and causing the lack of power.  Since I did all three and it ran perfect I don't really know what fixed it?

The original pump was a bit weaker.  I just bobtailed it up the street and it dropped to 4# under a quick jab of the throttle under load.  So I think the pump was weak and I might look to get a new pump for it.  Not sure if those are hens teeth or easy(and cheap)?  Not sure about the draw tube in the tank?  Could be an issue, I didn't run it down as low on this trip(only 240 round trip) and I only have one more race and not sure if I want to top the tanks off and have to deal with draining them to work on the drivers tank.  Have to figure that out in the next couple weeks.  I've wanted to replace box these tanks, but just haven't come up with anything I like(price wise).

I'm happy with the results, but wish I knew the root cause of the problem.  One thing for sure, I HAVE to get that governor issue fixed.  What a PITA that was, as it is getting much worse.  It really holds RPM when you try to shift and even stop for a light.  It sits at 1100rpm and then slowly drops to idle or sometimes I have to smack the pedal and it will drop to idle.  Whatever, it has to get fixed.  I hope I can find a pump shop that might just fix THAT issue and not charge me $3000 for a full rebuild?

[Freightrain]

So does anyone know the real part number for a fuel pump?  Should I just hit the dealer with my IJ pump number and go from there?

Something like this?
 

http://www.ebay.com/itm/E6-Fuel-Supply-Pump-2-Valve-PAI-P-N-ESP-3598-Ref-Mack-314GC227-Bosch-0440008015-/262616166868?hash=item3d2524b1d4:g:3N8AAOSwEK9T37NI&vxp=mtr

 

Mine has the old school hand pump on it and looks more like this:
http://www.ebay.com/itm/Mack-E6-Fuel-Supply-Pump-w-Primer-PAI-EPA-3587-Ref-319GC110-Ambac-SPA22B6363A-/252530193697?hash=item3acbf8f521:g:s4IAAOSwZjJU9M2T&vxp=mtr

Edited October 7, 2016 by Freightrain

[j hancock]

I have an old note listing 314 GC 366X for a Robert Bosch pump equipped inline six engine.  Don't remember if it had a primer on it or not.  Maybe a superseded number now.

Probably different number for an American Bosch pump?

[Freightrain]

Talked to local Mack dealer.  I need to use the serial number I got from a member to chase down the right pump.  Easy enough.

I also think I traced down my surging idle issue.  The last trip it was getting really bad and by the time I got home it really had to play with the throttle to get it down to idle.  I looked at it tonight and think it was my hand throttle bracket was getting in the way of my linkage and holding it above idle.  With the playing I've done with the linkage it was getting very close to the bracket and I the bracket was just slightly rubbing the linkage and holding it.  I cut the bracket and redirected it to eliminate that problem.  I started the truck and it works fine now.  No fluctuation at all.   Just a steady idle speed.

I have one more trip this weekend and then I'm done for the season.  I'm going to run the fuel down low so I can transfer from one tank to another so I can empty them and check the suction tube.  I really want to replace the tanks but that might have to wait for another year.

[Freightrain]

Well, the last trip out this past weekend was a good one.  The truck ran flawless and seems like it has a bit more Umph.  Fuel pressure never dropped and I ran the drivers tank down to 1/2 tank or so.  If there was an issue with the pickup tube I would have expected to see an issue.  So I'm thinking either the pump was bad or the filters were that clogged up(even if they looked okay).

My buddy says he was surprised at how well it ran the hills and we ran 70 mph without breaking a sweat.  I actually passed a line of traffic going up a pretty good grade running 70+ mph and still accelerating.  I even turned to Karen and commented to her about how well it was running.

I got a reman Mack pump for it today.  I put it on tonight and fired it up.  Still only about 15# at idle.  I can slowly rev it up and it would randomly slide up to 20# or so.  Not every time but a bit more then I could ever get out of the other two pumps.  Still think there is something else that is messing with it.  The return line check valve?  I haven't been able to unscrew it yet, but now that I don't need the truck I might get a bit more persuasive with a bigger wrench.

[j hancock]

Sounds like you are gaining on it.  With the season done, let the tinkering begin.  It will be interesting to hear what you find because you should be getting a couple more psi on a consistent basis.

[Freightrain]

I'm going to try again to get that check valve off the injection pump.  If that was leaking off then maybe that is why the readings fluctuate some?