Cummins N14 Celect Plus Hard Start Issue

I was reading that the N14 calls for a 7 micron fuel filter. The Baldwins are a 15 micron. The Donaldson that I have is a 10 micron. That should be better for now.

I also changed the fuel screen on the pump but that didn't help. I've always thought that this truck has lower power than it should (all though I've never had it on a dyno). I just put on a new turbo which helped but not 100%. My Tandem has a 3406B and feels like it has way more power than this N14 525HP.

 

I also got a 525hp n14 and it pulls like a train. You probably should also manually check your fuel pressure to see if your fuel pump is working correctly. Don't forget to pressure test your charge air cooler as well

 

OK. Thank you. I've got to find a fuel pressure gauge but I hope to check pressure tomorrow. I did a boost leak down test when I changed my turbo. I tried spraying the air cooler with soapy water but didn't see anything.

 

Do you have a fuel restriction gauge on this truck? I have seen the line go bad for them and cause hard starting and low power. If you have a 1/4 inch line going into your primary filter , block it off at the housing.

 

I have the filter restriction gauge but it doesn’t work. I’ll see if I can track down the line for it and see if it’s my culprit. Thank you

 

I changed the fuel filter to a Donaldson, changed the second check valve that I bought. There was one under the pump. Seems to start a little better but I only let it sit about 20 minutes. Fired after cranking about 7 seconds. I'll try starting it later after sitting for a few hours.

I wasn't able to check fuel pressure. There's not enough room on the valve on the back of the pump unless I pull off the ECU or get a better elbow fitting. This area has a line going to the dash (I assume thats for the filter gauge). Not sure if I'm trying to check pressure from the right spot.

I could have tapped into the line going to the fuel rail but I didn't want to disturb the line unless I'm sure my problem keeps up.

I won't be able to test drive until the ice in my area melts a little, hopefully next week.

 

I’m pretty sure I have either a bad pump, clogged line, or bad injector.

I drove my truck yesterday and it’s running rough between 1200-1500 rpm’s. Kind of a knock that clears up above 1500 rpm’s.

still having a hard start too.

not sure if I should do more troubleshooting or take it to a shop.

 

I also had loss of power and miss under load. Changed one suspected injector -did not help, new filters, new fuel pump, nothing changed.
Then my mechanic manually measured the fuel pressure at the pump, then disconnected the fuel hose before the ecm, put it in a bucket with fuel and measured again-big difference!
I installed new fuel lines, still no improvement. Then disconnected that fuel hose again and blew air through it, so fuel bubbled in tanks.
Since then got great fuel pressure and truck runs fine again

 

good idea! I could disconnect my hose before the ecm and run from a bucket of diesel. That will isolate if it’s a problem with my lines.

blowing air towards the tanks might be good too. I guess that could clear an obstruction in the pick up tube.

I’ll give this a try sometime in the next day or two. Supposed to get really cold here so might delay me. I’ll update what I find.
Thanks for the help

 

I checked the pressure today in 2 locations. I checked on the line that runs from the pump to the fuel rail. My gauge only went to 100 psi and I was well beyond that. The needle was buried.

but I tried on the little fitting on the back of the pump (where the line for my filter gauge is). I had no pressure on this line. Picture below. Shouldn’t that line have pressure?

makes me wonder if something is wrong with my pump.

I wasn’t able to try the bucket test. My battery got drained from starting the truck a few times. So I’m charging it over night.