Hopefully someone can help me out.

2001 Peterbilt w/8.3 cummins, I have two active codes:
spn1077 fmi14 Engine fuel injection pump controller
spn94 fmi10 Engine fuel delivery pressure

When the truck is first started I have 10psi fuel pressure coming from lift pump, after about 2 min pressure dros below 0psi to a suction. Is this right?

Someone please tell me this truck didn't just puke another CAPS pump in a years time.

Truck idles fine, had it running idle and also had it running at around 17-1800rpm for about 15 minutes no lights no problems. Take it on the road and it seems like it runs out of fuel, stop engine and check engine lights flash and sets these two codes every time.

Thanks for any help

 

If I recall correctly, the lift pump should supply a steady flow of fuel when the truck is running. I don't recall there being anything else in the system.

As far as a CAPS pump living less than a year. For a long time, there was only a 6 month warranty on them, because the average service life was only about 7 1/2 months. They couldn't afford the warranty costs. I am not sure if this has changed recently. I basically gave up changing those pumps, and let other people do it now. I can at least expect SOME life out of a VP44. ( note: If you think you got the short end with the VP.... think again )

Now, much like a VP system, if you lose primary pressure, it can cause a timing issue in the main pump. Most CAPS pumps, when they fail, fail completely, no start, no go. So, start with the delivery side, even bypass the stock system, and run from a remote reservoir with a pump and hose, to see what it does. That is the quick and dirty way to diagnose it.


Good luck

 

I'm no expert on these but do have a 01 FL70 w/ISC & am looking for my daay that I'll be troubleshooting it too.2-things I found out,I always put a qt of 2-stroke oil in every tank & these pumps like clean fuel so you might try changing your fuel filters if they've been on a while.