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PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - Printable Version

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RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - VNL670 - 07-01-2018

I did notice that after every PARKED REGEN I do, I get slightly better fuel mileage from 4.5 MPG to approximately 5.3 MPG. Then it starts to drop back down.
Here is what I am doing next week at the shop:
1. Overhead valve adjustment.
2. Fix the oil leak from the valve cover.
3. Injector leak test.
4. Pressure test the CAC.
5. Check turbo doser for leakage.
6. Check SCR for clogging.

I will keep you guys posted on the findings.


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - hhow55 - 07-01-2018

You mentioned earlier temps only go to 720f. May want to check for exhaust leaks, to your can. I bet you will find a leaky injector(s), also.


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - VNL670 - 07-02-2018

(07-01-2018 )hhow55 Wrote:  You mentioned earlier temps only go to 720f. May want to check for exhaust leaks, to your can. I bet you will find a leaky injector(s), also.

Just dropped the truck off at the shop. They are going to check for that also.


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - smorgan87 - 07-03-2018

You ever get over to atlanta area? Haggai is probably your best (and cheapest in the long run) bet on sorting all that out if your not able to do it all urself. Ive found the majority of mechanics don't know jack about isx engines. Judging by the mpg increase after a parked regen your creating WAAAAY too much soot (charge air leak, leaky injector/s, or EGR malfunction). Has the egr been cleaned?


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - VNL670 - 07-05-2018

I just got back from the shop. Major oil leak from injector #4 which I was aware of and thought it was the valve cover gasket. Does anyone know what could of caused it? And is it a cheap fix like a seal or something?[attachment=4026]


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - VNL670 - 07-05-2018

(07-03-2018 )smorgan87 Wrote:  You ever get over to atlanta area? Haggai is probably your best (and cheapest in the long run) bet on sorting all that out if your not able to do it all urself. Ive found the majority of mechanics don't know jack about isx engines. Judging by the mpg increase after a parked regen your creating WAAAAY too much soot (charge air leak, leaky injector/s, or EGR malfunction). Has the egr been cleaned?

I'll try to get up to Atlanta and swing by and even see if I can meet up with Rawze.


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - VNL670 - 07-06-2018

Mechanic said that someone had already ran the overhead on it but it was too too tight. Looks like they used the wrong gauges for clearances. He re-ran the overhead and fixed the mess up. He said that could be why I was getting bad MPGs. Guys, what other tests can I have the mechanic do while he in there with Cummins INSITE? I want to have him do the tests while the truck is in the shop.


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - smorgan87 - 07-06-2018

Fuel system leakdown to make sure none ur injectors are leaky. Maybe a cutout make sure ur firing on all 6.


RE: PLEASE help me! VNL670 with an ISX CM2350 4.4 MPG! - smorgan87 - 07-06-2018

That oil coming out an injector would have me real nervous. I might would wanna run a compression test.