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Tamip · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

I have a 2011 peterbilt 386 with the cm2250. For the last few weeks we have been chasing ghosts. This thing was running great until one day it started pumping out excess fuel out the exhaust. It was determined at that time that 1-3 weren't firing. Was told it could be the ecm. After 1st shop finished looking at it, it started running great again. I then left and drove approximately 80 miles from Duncan,ok to OKC when it started running bad again. Got towed to a shop in OKC and supposedly they had injectors and injector wiring tested. Was told both were fine (just got told at another shop that they were overfueling by 40%). Mr. hag connected to my truck remotely via insite and reprogrammed the ecm thinking it was a bad flash. Still ran bad. Replaced ecm and he programmed it remotely. Truck ran great for about 600 miles then started running like crap again. Got towed to current shop and they unplugged egr and it ran 100 times better. Left shop drove 10 miles and same issue.got towed back to shop where truck is right now. Put in 6 reman injectors yesterday and now 4-6 are overfueling. They think fuel relief valve is defective. Based on my reading it could be that or fuel pump or even the fuel pressure sensor. No codes on dash at all. Please help.

Rawze · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

Air getting into the fuel system?
bad wiring for injectors?

Tamip · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

Don't know about air getting in but supposedly the injector harness was checked at last shop and supposedly they put on a new one and still had same issues. I was told they then took the new one back off and put the old one on.

Tamip · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

How do you check to see if air is getting in somewhere?

Nilao · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

A tech would put in a clear line before the pump to see if any air was traveling through the line.

Tamip · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

Ok I will mention,that to them

Signature620 · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

There should be test points near the pressure fuel filter. Attach a line to the test point at the fuel filter inlet (preferably an orificed hose like the Cummins one) and check for bubbles. Any air entry before the gear pump will show up here and any issues after the gear pump should be noticable as external fuel leaks.

Tamip · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

Anyway of knowing if the fuel pump itself is the problem? The engine does run but like crap and smokes a lot of white smoke

Rawze · 12-05-2018, **(Subject: Cm2250 overfueling intermittently )**

(12-05-2018 )Tamip Wrote: Anyway of knowing if the fuel pump itself is the problem? The engine does run but like crap and smokes a lot of white smoke

white smoke can be coolant or oil too.