Jump to content

Injector line routing EC6-350


Recommended Posts

I picked up a 1984 Mack R model with an E-6 needing some attention.

The injection nozzle fuel inlet tubes between the pump and injectors 4-6 were out, along with the corresponding injectors.

The part that has me puzzled was that it seemed the inlet tubes were bent in such a manner that the sequence at the pump, from front to back was line 1, 2, 3, 6, 4, 5 (vs 1, 2, 3, 4, 5, 6).  It has a UTDS / Bosch / AMBAC PLM Model 300 injection pump on it.  Did somebody mess with this thing and bend lines all screwy?  Seems odd the tube/line sequence would not be 1-6 front to back on the pump.

I had it running that way, but was pushing a lot of fuel out the exhaust.  It also had a 45 second interval where rpms would drop way down, then pick back up (sticky governor after sitting a number of years)?

Thanks in advance for thoughts/advice.

Link to comment
Share on other sites

I think its just a puzzle..  they are in order 1-6,,  front to back. the last one I did, I had new lines and still had to mock them up individually to be sure..  (Ambach pump). the part numbers were Volvo numbers and I learned that part of the number was the position, however, someone took a few of mine out of the bags, so I had to build the puzzle. There are a bunch of guys here that could do a better job of helping you..  of course if a line has been bent, that will surely interfere. I cant remember if #5 goes in first, and then 4 and 6... anyway,  I bet Glenn chimes in on this, theres a few others as well...   jojo

Link to comment
Share on other sites

I took a picture and did some markup to help show what I'm talking about, although you are tracking jojo.

I've got injectors 1-3 at the shop getting pressure/pattern checked, so the tubes are loose at the pump.  It's the 4-6 positions that are definitely hand bent.

It appears my turbo comes out straight, others seem to kick up and have more room underneath to run tubes.  I attached a pic of an E6 4 valve from the interweb (although you can't see turbo well in my pic).  Thanks, Scott

Injection Pump tube routing.jpg

Engines-Mack-E6-Injectors 4-6 2.jpg

Link to comment
Share on other sites

Your lines are defiantly out of whack And the ambac pumps after warmed and years of use would surge as you described from Governor wear!The other thing that will make them surge is the throttle lever  breakover spring being loose and worn!

  • Thanks 1
Link to comment
Share on other sites

fjh is right on that one, check that breakover spring first. If that's not the problem you can check his idea about the governor by dropping the front or back of the truck in a low spot so the truck isn't level. If the idle smooths out then the governor is the problem.

Link to comment
Share on other sites

4 minutes ago, h67st said:

fjh is right on that one, check that breakover spring first. If that's not the problem you can check his idea about the governor by dropping the front or back of the truck in a low spot so the truck isn't level. If the idle smooths out then the governor is the problem.

Thanks guys, seems I'm battling a couple problems here. Going to verify injectors are decent (1), find new/used tubes or "adjust" existing to fit correctly (2), and then (3), see if my surge problem is still present after that.

Kinda surprised it was running with that drastic of timing problems on cylinders 4-6!!

  • Like 1
Link to comment
Share on other sites

All right, all six injectors checked out/cleaned up/corrected.

Fuel inlet tubes 4, 5 and 6 "adjusted" to line up correctly on the pump.  Definitely plan to replace them, they were in rough shape before my work over, they certainly aren't any better now...  Truck does run a LOT better with no fuel seeping out turbo/exhaust connection.

Still have the surge right after start up, even before it gets warm - fjh and/or jojo, is the throttle lever breakover spring shown in the photo?  I'm not counting out a worn or sticky governor though, it sat for a number of years.  Will try your idea of getting the truck unlevel and see if the surge goes away h67st.

The truck supposedly had an in-frame done and what looks like new heads. Ran like crap and prior owner started to work on it, but didn't get it done.  So I'm unraveling some of the history, but concerned a break-in was not done and that I might wash down cylinder walls.  Going to check if any local shops can put it on a dyno - I don't have a trailer/load to put on it for a proper break in.

throttle lever breakover spring.jpg

Link to comment
Share on other sites

that lever should still be available at your local pump shop...  just for kicks, do a 'Halo test' on a piece of cardboard..  put a decent drop of the engine oil on the cardboard and watch for a halo to form around the outside of the droplet..  if one forms quickly, (within seconds) the oil is saturated.  if it is slow to form, then mabey you dont have a lot of fuel in the oil..   of course oil analisys is the best way.  jojo

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

15 hours ago, sdthoren said:

All right, all six injectors checked out/cleaned up/corrected.

Fuel inlet tubes 4, 5 and 6 "adjusted" to line up correctly on the pump.  Definitely plan to replace them, they were in rough shape before my work over, they certainly aren't any better now...  Truck does run a LOT better with no fuel seeping out turbo/exhaust connection.

Still have the surge right after start up, even before it gets warm - fjh and/or jojo, is the throttle lever breakover spring shown in the photo?  I'm not counting out a worn or sticky governor though, it sat for a number of years.  Will try your idea of getting the truck unlevel and see if the surge goes away h67st.

The truck supposedly had an in-frame done and what looks like new heads. Ran like crap and prior owner started to work on it, but didn't get it done.  So I'm unraveling some of the history, but concerned a break-in was not done and that I might wash down cylinder walls.  Going to check if any local shops can put it on a dyno - I don't have a trailer/load to put on it for a proper break in.

throttle lever breakover spring.jpg

Yup if that spring has any slack either side it will can surge! Unfortunately as you obviously know the breakin is important Once everything is glazed over its hard to correct! The best breakin  is hard work! warm the engine to temp And give it all its got loaded! in moderation! bar non the best thing you can do for a new engine or rebuild ! Odiously some common sense is required here however................... 

  • Thanks 1
Link to comment
Share on other sites

On 6/17/2022 at 6:24 PM, sdthoren said:

Still have the surge right after start up, even before it gets warm - fjh and/or jojo, is the throttle lever breakover spring shown in the photo?  I'm not counting out a worn or sticky governor though, it sat for a number of years.  Will try your idea of getting the truck unlevel and see if the surge goes away h67st.

Yes, that's the breakover spring.

Link to comment
Share on other sites

Thanks guys - halo test was good, although with the extended oil change setup, there's a lot of oil there!  Break over spring didn't have any slop - directly working the lever (vs linkage from pedal) didn't indicate any dead spots where the spring wasn't tight.

I didn't work on the truck much since Friday.  I'm trying to minimize any low rpm/idle time on the engine as well (due to unknown engine break in after in frame).  So I'm gathering troubleshooting ideas to maximize benefit of run time.

Chasing some cooling system issues as well. Lot of reliability things creep in when a truck sits for several years (or a decade!).

Thanks again for all the advice and input!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...