Cummins problems HELP!!!

[MandBtrucking]

Ok so I got a 870 isx in my 05 Peterbilt little back story I bought this truck back in October now I have never been around a Cummins I was a cat man and decided I wanted something different ok so this thing has 100k on overhaul and injectors now the lift pump is hooked into a toggle switch (I don’t know why it was like that when I bought it) egr is unplugged now when you start it cold the thing sounds like it is going to fall apart popping and missing banging and clanging was told by a few people that is how they are. Once it warms up runs okish it has a miss a miss so bad that I have been chasing ujoints and ride hieght because it gets this buck going on at higher speeds like 60-65 and only at neutral throttle throw it out of gear and it quits didn’t really bug me to much but been keeping track of my fuel mileage here lately and it is clear down to 4.5 I pull a pig pot but most the time I am loaded with 3000 pounds of baby pigs I think it needs to do better and it had just gradually went down now I can run down the big road for a 170 miles get off the ramp and I have a dead throttle for a split second I let it idle for an hour load and go to take off it acts like it is running out of fuel then boom takes off again I let it idle for 10 minutes it doesn’t run smooth at all until I get out on the road and take off no loss of power in my opinion just runs like crap I can feel it in the throttle and seat I took injector actuators off on Wednesday took apart and cleaned them they didn’t look that dirty to me put them back in same location didn’t have time to do timing but got it goin and it ran about the same as it always has the now today went out and fired it up didn’t really pay attention to how it sounded let it warm up and took off about 20 miles from home I noticed it IT WAS RUNNING AMAZING!!!! No missing not rough or anything I didn’t get to excited because my luck it would just go back to the way it was once I stopped got to the barn to load idled it up I always do loaded took about an hour went to take off and it didn’t attempt to die like normal so I ran it over 600 miles ran amazing nice smooth stopped to get fuel checked my mileage and I was up to 5.2 pulled out and it started missing again and did it all the way home bout 120 miles now I don’t know if this has anything to do with it or not but my jakes run good and strong until about 1200 rpm then it is like you start shutting cylinders off it never did that before... now I know I need a overhead run I don’t like shops working on my stuff to much in my opinion why pay for something that I can do and will have to do in the end now if it was a cat I would jump right in it but beings how i am new to the world of Cummins I need some help here what do you guys recommend??? P.S. after talking to some guys that knew the guy that owned my truck prior sounds like he has been chasing this problem for awhile but i think he just gave up any help would be appreciated!!!!

[Rawze]

sounds like someone has butchered that thing up?

Maybe take it to Mr. Hags and get some professional help with it?. It is highly likely the last guy chased the problems and now you face them.

Also could be bad or wrong program in ecm?.

Wiring problems?

None of those things you describe are normal with an ISX 870.

[MandBtrucking]

I was going to start with replacing sensors The exhaust pressure sensor cam sensor stuff like that hoping it is an easy fix lol something he overlooked

[Wiseman]

What you’re describing sounds like unstable/unpredictable ECM mode do to unknown butchers copy/paste work . Add to that unplugged EGR and all you have is trouble.
My advice is to get in touch with MammBurt and get this thing straight immediately!
Everything else you need to know about your engine is on this site.
Reed, learn , work on it yourself and be happy.

[MandBtrucking]

Who is mammburt

[Waterloo]

(01-18-2019 )MandBtrucking Wrote:  Who is mammburt

A member here, PM him.

[MageRoyal]

(01-18-2019 )MandBtrucking Wrote:  Who is mammburt

mommaburt - http://rawze.com/forums/member.php?actio...e&uid=1079

[ynot]

Without knowing what's going on in the ecm tuning wise, here's a couple ideas too check look into.

Is the truck smoking on take off or gear changes? Check too see if the fuel temp sensor is plugged in or if buddy threw a resistor too trick the fuel temps for more power it just causes way too much fuel an shitty mpg an doesn't help anything in my opinion, the truck I bought a couple months ago had one hiding on it an it didn't help idle much. As your looking at the item the fuel temp sensor is on the left side at the bottom kinda behind the fuel filter.

You said the egr valve is unplugged have you tried plugging it back in? An what happens any check engine lights? I wonder if buddy was trying to unplug it while the valve was closed. In an attempt too get it in non egr gimp mode after reading some shitty info online. If that valve wasn't closed when unplugged it's still flowing an messing with everything idle an fueling going down the road, an will most definitely cause the truck too run like shi#t. If the egr valve was unplugged the egr temp sensor is probably unplugged as well.

There used too be a little filter/screen after the pre filter right before the lift pump that was known for plugging up an causing grief in earlier isx's, it was a brass fitting screwed right into the lift pump an the fuel line connected too it.

Do you use the lift pump too start the truck? Does it start fine with out it or just crank tell the lift pump is turned on? Have you tried driving the truck with the lift pump left on? I wonder if you've got a bad check valve in the ifsm or an air leak somewhere causing too loose prime.

[MandBtrucking]

I will try all that stuff yes it smokes on start up and in between gear changes I use the lift pump to start the truck I have tried running it down the road doesn’t seem to help at all it won’t start without it being on at all that was my first thought was it is loosing prime but it shouldn’t take that long to work the air out of the system should it?