Gear_Grinder

Rookie Expediter
Researching
I know a small bit of the MBE we do deal with a lot of them not as much as Detroit and Cummins. Is the code still showing the #6? If so I would say yes it definitely could be. Honestly I know it’s pricey I would always recommend all of them but I know it’s not always fees able to do that and correcting the problem. It absolutely could be the unit pump check the connections try to follow the harness and make sure it’s not the wires a lot of times when persistent reoccurrence people seem to think the part has failed again but bad wire, harness could be the problems. Make sure they replace the injector line they are not to be reused. It could be multiple problems but I would stay on the track your on. I mean it could as severe as cams or internal motor issues or as simple as bad fuel and other issues throwing the code and I can’t rule out the injector themselves if it’s a reman injector they can go bad at immediate install or last forever. I would start with inspecting the wires and unit pump make sure everything looks good and dry. Maybe pinched oring during install so browse around. See for harness and wire issues a lot of dealers have test harness where they just instal and just she how they run with those. I can tell you them Mercedes is the worst motor. But I did see people on here had good runs but there is always going to be those select few that will run amazing.
 

Boatcat

Seasoned Expediter
Owner/Operator
US Navy
Thanks, I appreciate the help.
I have a load to do tomorrow and then headed home for a week.
I will be checking all the harness connections, coating them with dielectric grease and giving it a good close inspection.
The oil and fuel filters were just done at the same shop that changed the injector.
The injector was a new one ,not a reman. New line also.
If I do need a unit pump, I will make sure to have a look at the cam lobes to check for excessive wear or damage and if that's the case, the truck will be parked. I will go drive Class A until I make enough money for a new short block and install labor.
Replacing the injector harness with a known good one is a great idea to isolate it down to the unit pump. Maybe even switch 5 and 6 pumps to see if that changes anything.
I'm a decent mechanic, could I change the unit pumps and harness myself?
I've been doing a Lot of idling lately and have noticed the check engine light does not come on until the engine is at normal operation temps, on for a second or two, then off for a while, especially at high idle.
Thanks again. This all helps as the closest shop that can work on this is 200 miles from my home.

Sent from my SM-N910V using EO Forums mobile app
 

Gear_Grinder

Rookie Expediter
Researching
I got to take care of some stuff this evening and I’ll get back to you. Talk to you in a bit though.
 

Treadmill

Veteran Expediter
Owner/Operator
Thanks, I appreciate the help.
I have a load to do tomorrow and then headed home for a week.
I will be checking all the harness connections, coating them with dielectric grease and giving it a good close inspection.
The oil and fuel filters were just done at the same shop that changed the injector.
The injector was a new one ,not a reman. New line also.
If I do need a unit pump, I will make sure to have a look at the cam lobes to check for excessive wear or damage and if that's the case, the truck will be parked. I will go drive Class A until I make enough money for a new short block and install labor.
Replacing the injector harness with a known good one is a great idea to isolate it down to the unit pump. Maybe even switch 5 and 6 pumps to see if that changes anything.
I'm a decent mechanic, could I change the unit pumps and harness myself?
I've been doing a Lot of idling lately and have noticed the check engine light does not come on until the engine is at normal operation temps, on for a second or two, then off for a while, especially at high idle.
Thanks again. This all helps as the closest shop that can work on this is 200 miles from my home.

Sent from my SM-N910V using EO Forums mobile app
Why don’t you send greasytshirt a pm and ask him about it. He is our resident mechanic?
 

piper1

Veteran Expediter
Owner/Operator
Sometimes folks don't like the answers from someone who knows*...so they keep asking others until they hear what they want...right or not.

*greasy knows
 
Last edited:

greasytshirt

Moderator
Staff member
Mechanic
Don't look at me! I still haven't figured out how to make a Sprinter happy.

Edit: I'd do a compression test to make sure the base engine is ok before throwing a bunch of parts at it.

Sent from my XT1585 using EO Forums mobile app
 
Last edited:

Boatcat

Seasoned Expediter
Owner/Operator
US Navy
Did that. Checks out ok.
I'm going to pull apart the engine harness connections make sure they are clean, coat them with dielectric grease and see if that changes anything.
Thanks.

Sent from my SM-N910V using EO Forums mobile app
 

Worn Out Manager

Veteran Expediter
Owner/Operator
US Air Force
When I started 3 years ago I thought about Str8 but took the lazy way in and got a van. Sure I have had some mechanical issues but when I read what some spend on a Str8 I think I made correct choice

Sent from my XT1710-02 using EO Forums mobile app
 
  • Like
Reactions: ntimevan

Boatcat

Seasoned Expediter
Owner/Operator
US Navy
When I started 3 years ago I thought about Str8 but took the lazy way in and got a van. Sure I have had some mechanical issues but when I read what some spend on a Str8 I think I made correct choice

Sent from my XT1710-02 using EO Forums mobile app
I just had the bad luck of buying a truck from a cheapskate, liar and someone who did not properly care for the truck.
I can deal with a lemon but I bought the whole orchard...

Sent from my SM-N910V using EO Forums mobile app
 

Gear_Grinder

Rookie Expediter
Researching
Hey Boatcat back yeah I would definitely do that honestly like I said usually when it’s a repeat several times it does tend to be wiring some. But remember I work at freightliner so I can look up anything freightliner, western star, sterling, we do have options for internationals but I haven’t been trained on it and really never wanted to be. We use to do sprinters and Mitsubishi to but dropped both of those. I have access to Mercedes, Detroit’s, Cummins, Cat and Maxforce (for international which I have no training for) I’m also ASE certified in everything except for drivetrain and parts and freightliner aftermarket parts. Anyways what I’m getting at is I have access to parts catalogs and repair manuals and electrical schematics and diagrams etc... for your truck so anything you need I can try to access for you just let me know. I think I’m able to at home to. Some things are not accessible but most all I need is the last 6 of your vin just let me know. I pulled a manual for the unit pumps though and the fuel lines. Also showed you my ASE so you don’t think I’m fooling with you. It’s hard to diagnose without having it but if you need to know parts or manuals I’ll see what I can for you to try and get you going or have to do yourself or have info for a local freightliner you are near. I attached 2 manuals to this so check them out of you need them. Let me know how you make out.
 

Attachments

  • mercedes 900 injector unit pump.pdf
    286.5 KB · Views: 9
  • mercedes 900 hpfl.pdf
    925 KB · Views: 0
  • 2D1A86E7-441F-4B52-A2A0-D11F661DFD4F.png
    2D1A86E7-441F-4B52-A2A0-D11F661DFD4F.png
    785.5 KB · Views: 15
Top