08-11-2015, 12:34 PM
MWrenchBig loss of power
Had a good one this weekend. Went to Mojave to officiate at a SCTA event. (Bonnevile was cancelled due to heavy rains a couple of week ago) While setting up the equipment, there was a big loss of power, No boost and would take forever to get to 35 MPH. Boost would come on slowly starting about 5 PSI and gradually getting to 15 PSI as the RPM would build.
Called a few diesel mechs I know and they all seemed to agree that it was fuel filters. I knew it wasn't the turbo because there was no smoke, it had to be a fuel delivery problem.
I was able to locate fuel filters at NAPA and got them ready to install after the event on Sunday. I made a list of things to check because It really didn't make sense to me about fuel filters as this loss came on suddenly, if filters were getting clogged up I was thinking it would be noticeable over a longer period of time.
List I made:
1. Fuel lines clogged or leaking
2. Fuel filters
3. Lift pump
4. Fuel shut off solenoid
5. Boost modulator diaphragm.
6. Injection pump
After the event, I parked and started to check the easy things first. Once I would start the filter change I would be committed and had to continue until finished and it is a messy job.
Checked and looked for any signs of fuel leaking around the fuel lines and filters, nothing found. Checked the lift pump, it would get firm after about 2-4 pushes so that seemed normal.
Went to the fuel shut off solenoid and checked for movement, along with throttle movement. Throttle seemed normal but the solenoid didn't seem right, I played with it a bit and then something went KLINCK! I could not get it to move at all! More wiggling and it went KLINCK again and viola, now I could pull the solenoid all the way up.
Started the engine and had full power again. The fuel solenoid was not pulling all the way up so therefore the injection pump was limited on fuel delivery. I closed up and headed home, so happy I didn't have to change fuel filters there and VERY HAPPY it wasn't anything more serious!
Cummins is VERY PROUD of this solenoid, list price is $389.00, stupid expensive, will be checking around today for an after market unit. as this morning the solenoid was again not pulling all the way up. I may have to change the linkage as well because it appears that once it is freed up, it will pull all the way. Something is jamming the lever. With over 235K miles, it has been actuated a lot of times!
08-11-2015, 11:45 PM
Gary CarterJust want to comment on fuel filters. I never change them unless they become plugged and that has happened to me when I got come bad fuel years ago. Went thru a number of filters until we got rid of most of the fuel. So I say if you have to change one then get a couple of extra as you will probably need them.