N14 celect issues
 

We have a N14 celect that is missing under load. It seems to clear up above 1500rpm, and it doesn’t do it at idle, or when free revving it. I have unplugged injectors whole it’s idling, but all 6 make it miss. Temps on the exhaust manifold seem to vary between 120-200, with most hovering around the 130 range, and #4 being the only one distinctly higher at 200F.

Engine number is 11740205, Best I can tell from the tag.

Anyone have any trouble shooting advise?

Thanks,
Eric

It's a pain in the ass, but being that I'm sure you have at least one bad injector.
I've had customers that will purchase one injector, pick a cylinder and replace it. If that doesn't work. Put the one you just removed into the next cylinder, and so on until you hit the correct cylinder. Depending on mileage, you may want to think about buying 6, and be done. Cummins usually has a buy 6 get one free rebate going on.

This truck doesn’t get driven a lot, it’s got a 5000 gallon manure tanker on the back of it, so it spends most of its time in the barn when we can’t spread. Gets used twice a year, maybe no more than 1,000 miles a year. But a lot of them are field miles spent running wide open.

I was thinking it was an injector as well, which sucks because we put 6 new injectors in it a couple years ago.

Thanks for the info snedge. Looks like we might just have to buy one and start swapping.

That's about the only way to do it.
The miss/Stumble usually happens so fast that Insite won't pick it up, and cutting out cylinders during a road test is worthless. Insite allows us to do a cylinder performance test that will sometime smoke out the bad cylinder, but mostly we end up doing the process of elimination method. We can swap an N14 injector in under an hour in most cases, but it can still be time consuming.


If the truck sets for awhile, you could always pull all six and send them out for testing.

Can just about any competent injection service test them?

We use Diesel Controls over in Massillon Ohio

That’s not too far. We bought the injectors from mountaineer diesel

While we are on the n14 issues, sometimes both of our trucks with n14s roll for a very long time before they start. I briefly watched a video awhile ago that show a fuel fitting getting plugged up causing hard starts. Is this valid?

Yes, that is accurate. The one fitting by the ECM is a check valve. If anything gets in that check valve and causes it to stick open the fuel will drain back and cause an extended crank after they’ve sat for a bit. It’s been about 8 years ago that I dealt with it on an N14 Celect Plus that I had.

That makes sense, cause they always start if you crank them long enough.

Thanks for the help

On my N14 the fuel filter was on the back of the pump which meant the fuel was not filtered when it came thru that check valve. Mine had a piece of what looked like coating off of a wire stuck in it holding it open. An old Cummins mechanic got me all the parts (except 1 line I had to get made) to put a stand-alone fuel dampener on the pump, and move the filter up stream to where the fuel was filtered when it came thru the check valve. All OE parts, cost about $250, took a couple hours to do, and made a world of difference in how it started, and never had to mess with it again.

Run the motor and use an inferred thermometer on the manifold and to check each cylinder. A good way to test and see which cylinder may be giving you a problem.

Sent them up to diesel controls, one bad injector and two on the verge of going out. Being as new as they were, I was advised to check out the fuel filter situation. Turns out someone put a filter delete on the pump filter, and only used the water separator as a filter. Only 12 micron:bang

So we reinstalled a 5 micron on the pump filter. Napa 3406, does anyone have a cross reference for a 2 micron filter that will fit the same?

I also took both fittings out of the fuel cooler behind the ECM and neither fitting had a check valve in it

Recmmended filter is a FS1000, Donaldson version is P551000 and is 10 micron, I’m not sure I would want to go much smaller as they can restrict flow.

There is a P551311 that is 3 micron that says it is same flow as P551000, if need be run that one on the pump if you have room and the 1000 on the frame mounted filter.

Well after taking it for a drive, it seems to lack the power it previously had. Do you think the 5 micron could be restricting it, or if the injectors were not setup properly could that cause it as well? I was having trouble finding someone to tell me how to properly install the injectors. We set the valves and torqued the injector to 105 in lb.

I think it’s the Napa filter restricting it, not the micron.

I cannot run Napa filters on the engine in my puller.

Interesting, according to the interweb the 3406 filter will flow 12-15gpm. Is that not enough?

No way it flows that much, the Donaldson filters I mention flow 111gph, that is under 2gpm.

I got the 12-15 directly off a wix website. I think I’ll try putting the filter block off back on it and see if that brings it to life. If it doesn’t I know the filter isn’t the problem.

Thanks smokincat. I’ll let you know what I find out.

At what pressure does it state that flow? Wix might make Napa filters, but they're not the same.