Another 870 thread- Engine vibration
09-17-2018, (Subject: Another 870 thread- Engine vibration ) 
Post: #1
Another 870 thread- Engine vibration
Greetings everyone, I'm not terribly good at this so please bear with me.

2005 870 in a 379 dump truck
534,xxx miles
De-mandate of questionable origins (I know, not good, but I didn't do it), was done at 340k miles, bought truck at around 400k miles.
No real major issues until now

The motor seems to have a slight vibration when driving, more pronounced when under a load and worse when engine braking. Has been going on for almost 2 months now, which is making me crazy. Let me backfill the problem for you all:

Early this year I noticed my mileage getting worse, usually around 6, then declining to between 5.5 and 5, depending where I was hauling. I also got a raw fuel smell coming out of the exhaust. Some guys said it smelled like a regen system.

Had talked to Gearhead last year about getting out there, but never made the trip, finally decided it was time. Unfortunately I didn't specify that I wanted him there(too check/fix the programming), so found out too late that he is/was apparently working at home most of the time. Anyway, the other guys there checked it all out- did all the cylinder/injector tests, bubble test( #1 was leaking) and ran the overhead. Now understand that the truck still ran fine, no real loss of power or driving issues that I could tell.

That was May, so I saved a few pennies and made an appointment about a month or two later to get the injector done at a local shop that does Cummins. Had it replaced with OEM Reman and did fuel filters as well. They have done other work for me and no issues, until now. After just a few days, I noticed that the engine had developed a little bit of a miss sometimes, and would run a bit rougher it seemed to me. Saw a good excuse to fire up the Insite to run a few tests and see what I could see. Managed to change something in the cutout test so now it will only do 1 bank at a time, or each cylinder in that bank, instead of each cylinder individually, so now it's worthless for that!

At least it can still read codes, and it showed a 2312- Timing Actuator #1 circuit error. I had bookmarked the post about actuators(http://rawze.com/forums/showthread.php?tid=110) so I pulled them off, cleaned really well, and reinstalled. Ran better, but not great. Grabbed one off a friends 871, cleaned it, installed in #1 slot, and didn't do much. Swapped #1 & #2: Holy crap, it was a whole new truck... For about 2 days. Then back to the same. Removed both, brake kleened really well, reinstalled, ran really well for a day. And that pesky 2312 was back, so I went ahead and replaced both actuators with OEM Remans. Again, ran good for couple days and then crap again.

----

The summary is that the truck ran just fine until the injector was changed, then it's been downhill ever since. Well, actually, it went downhill and now it's stayed the same.

I hate taking time off to go on flights of fancy, so that is why I've laid this all out here. My hope is that I can get a solid starting point so that I'm not wasting many days running around fruitlessly and can get some actual results.

So...

-I know the hot sauce is headed my way for that demandate that hasn't gotten fixed properly

-Yes, dampener has been changed

-Does my overhead need re-checked? I don't have the proper tools yet, but am working on it.

-Many threads on here about replacing the various harnesses on the motor. This truck does not lead an easy life, and at 13 yrs old and half-million miles, maybe not the worst idea?

- Could the Reman injector be a dud? Since I can't do diagnostics until a new Insite shows up I'm swimming in the dark.

-Should new Fueling actuators be in my future as well?

-Pretty sure motor and tranny mounts are not in great shape, I have them, just haven't gotten them in yet

Many thanks to anyone who has an idea of where to start. I don't mind being the idiot, as long as someone else can benefit from my idiocy!
replyreply
09-17-2018, (Subject: Another 870 thread- Engine vibration ) 
Post: #2
RE: Another 870 thread- Engine vibration
You may need new actuator plugs. The connectors inside tend to stretch over time and get loose...
replyreply
 Thanks given by: Rawze , ZeroNthedark
09-17-2018, (Subject: Another 870 thread- Engine vibration ) 
Post: #3
RE: Another 870 thread- Engine vibration
That whole harness looks pretty rough, so I'll get one ordered.
replyreply
04-26-2019, (Subject: Another 870 thread- Engine vibration ) 
Post: #4
RE: Another 870 thread- Engine vibration
==Well, I'm pretty stuck, so figured it was high time to dust this off and see what happens==

I won't bore anyone with mundane details yet, so the short version is thus-

Finally had no choice but to order a new harness. Had tried to do some troubleshooting by replacing wires that were obviously in terrible shape, just to see what did and didn't work. Truck had gotten so bad it was actually activating 3rd stage of engine brake randomly at idle, amongst other issues. Got it overnighted, installed today and now the truck will not start. Won't even try to fire. And I drove it home before taking old harness off.

Triple checked all connections and everything "looks" good. The harness fuse is good, besides being brand new. No bent or broken pins in ECM.

Tomorrow is another day, but until then any ideas are greatly appreciated.
replyreply
04-26-2019, (Subject: Another 870 thread- Engine vibration ) 
Post: #5
RE: Another 870 thread- Engine vibration
Have you got insite running yet? You can monitor the things such as whether or not the fuel shutoff solenoid has been commanded open or closed. Test the shutoff solenoid with a voltmeter or testlight to see if there is voltage there with the key on. Does the liftpump run with the key on? Need to know what is working and what isn't.
replyreply
 Thanks given by: Rawze , ZeroNthedark
04-27-2019, (Subject: Another 870 thread- Engine vibration ) 
Post: #6
RE: Another 870 thread- Engine vibration
The problem with your Insite not cutting out single injectors is that you need SP5 (service pack 5)
replyreply
 Thanks given by: Rawze , ZeroNthedark
04-27-2019, (Subject: Another 870 thread- Engine vibration ) 
Post: #7
RE: Another 870 thread- Engine vibration
Whoops, I knew I should've re-read and edited my initial post.
——————
- Fixed the computer problem by picking up an Inline 6 and upgrading to 7.6.2 version. Now it all works correctly.

- Got around 11.97 volts at the shut-off solenoid. And lift pump works fine, runs for its 2 minutes like it should.

Figuring I need to pull new harness off and reinstall old one, just to make sure it does still run.
replyreply
04-27-2019, (Subject: Another 870 thread- Engine vibration ) 
Post: #8
RE: Another 870 thread- Engine vibration
What does Insite say the status of the shut off solenoid?

What is your fuel pressure getting to while cranking?

Using Insite, Go to Data Monitor/Logger then Hard starting. It'll bring up a list of sensors and parameters that are involved with starting the truck. Start your troubleshooting there. Make sure those sensors are in the correct position for starting the engine. Also make sure they are reaching the correct pressures and voltages during cranking.
replyreply
 Thanks given by: ZeroNthedark
04-27-2019, (Subject: Another 870 thread- Engine vibration ) 
Post: #9
RE: Another 870 thread- Engine vibration
I also find it odd that your not reporting any codes....
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