You are here:

Truck Repair/Cummins N-14 Engine


QUESTION: This is a 1993 N-14 Clect. It was diagnosed with a bad ECM, that was replaced with a rebuilt. It then logged a 121 fault code, for the engine position sensor, and it was replaced with a new one. Now there are no fault codes.      
But the engine has a surge or bark to it, at an idle and also high idle. There are no air bubbles in the sight glass, and the fuel pressure is running 155 psi at an idle and around 175 psi at high idle. What could cause this surging.

ANSWER: Have you singled out the injectors to make sure they are all working? The other is has the overhead been run recently? Was this doing this prior to ecm replacement and the crank position sensor?

---------- FOLLOW-UP ----------

QUESTION: No sir, I had unplugged each injector atthe pass-thru connector,and they all seem to be hitting, but I was told this was not always an accurate way of cutting out the injectors. I'm in the process of locating an electronic tool, such as an E-chek, ect. Also I have not ran the overhead, or checked it myself. The owner says It wasn't surging like this before the ECM went bad. I was leaning toward setting the overhead, but it's going to be a tough one,as this engine has jakes, and is laid sideways and halfway under the cab of a Ford L-9000.

Just checking to see how everything has come out and if you figured your problem out.

I figured you had unplugged the injectors. Do not believe its a injector issue anyway but its best to try you never know. you get more of a missing with a injector not a surge. Would definitely try to get a scan tool. Did you check for air in the fuel between the tanks and the pump or out the return line. If you did between the tanks and the pump i would try doing out the return line and see what that gives you could be a possible bad injector o-ring or cup. Might also try wiggling your harness around your ecm possible you have a intermittent problem there since youve moved that harness replacing the ecm.  

Truck Repair

All Answers

Ask Experts


Jeff Drumm


I Can answer any question pertaining to semi trucks and trailers. Have no experience in the automotive field so not able to help in that area.


My experiences in Semi Trucks is. I own my own truck and i presntly maintain a 80 truck fleet. Can handle any questions pertaining to a truck have tore apart and rebuilt every aspect on them. Fleet I deal with is Mainly Volvo trucks and a handful of freightliners. Work on automated transmissions on a daily basis along with carrier apu's. With engines my specialty is the 60 series Detroit but do work on the cummins isx the n-14 and the ism. and also the Volvo engines.

Have a College Degree from university of northwestern ohio in diesel and agriculture mechanics. Have 10 years behind the wheel driving a truck and 4 years working on trucks full time. Also have grown up on a farm so have been tinkering on trucks and tractors all my life.

Awards and Honors
I've gone through online schooling and have received certificates from webb wheel, Timken and Volvo academy.

©2017 All rights reserved.