Fuel restriction spn95 fc 2343

[W9L]

So, in the last couple of weeks I have been getting this code and associated derate. Sent a driver out in it and it did it 4 times in one trip. You can shut it off for a few minutes and it seems to get rid of the derate. After he got back, I replaced all the stratoflex fuel lines, the return splitter tank vents, restriction sender in top of primary filter head and filters. After doing this the engine ran SOOOO much smoother and power and mpg up. I had been suspicious it was sucking air... I ran it 3000mi before it did it again. Also sounds like it is sucking air again. Just a flutter in exhaust. I put an inline sightglass between primary and secondary filters and find no air after it starts and runs a couple of min at 1000rpm. Injectors were all replaced about 80k ago and fuel pump is quickly approaching 400k. Everything I find on Quickserve seems to lean towards a restriction in lines for at primary filter. The restriction gauge with new sender rarely gets above 2in hg. Is this the same sensor that ecm reads and uses to calculate differential pressure ? I find it interesting that it was doing it several times a week before I replaced all the stuff and then waits 3000k before it repeats.

[Rawze]

will it pass a rail leak-down test?

[W9L]

Still waiting on inline 6, so I really don't know. Put 6pack of injectors in in Feb. Would not shock me if it had a leaker. The test you refer to is done through the ecm isn't it? Something straight forward I can get one of the guys at KW to run through pretty quick. So many people with Covid /Delta around here the shops are all a week behind. And quite honestly I prefer to do or my own troubleshooting or oversee it anyway. Just baffles me how great it ran for the first 2000k mi after the lines and such were replaced then it started going downhill for the next 1000k mi until it derated. Made me wonder if possibly the pump might be getting weak and by replacing lines and such it might have masked the problem temporarily?

[Mirafail]

Probably a long shot but I'm dealing with what sounds like this exact same issue on a 2010 386 with a cm871, did you ever figure out the root cause with this? Driver says it's been doing this for going on 3 years. Used to be very intermittent but now seems to be happening more frequently. Definitely appears to be worse during the summer months and especially on hotter days. Or if anyone else has any insight or suggestions, I'm all ears. Thanks!

[Nhramember]

(07-04-2021 )W9L Wrote:  So, in the last couple of weeks I have been getting this code and associated derate
...

Did u ever find your problem because I’m having the same exact problem. Thanks nate