codes p0251 ,p0370

[chevy6.5]

I have these codes driving me nuts, can anybody help , started on a trip from Fl. to N.J. I got to the S.C .broder stop and when I got back in and started down the road the ck. light cam on found a auto zone they ck. the codes p0251,p0370 was on a sat nobody to work on it it drove a little lazy, so I continue to n.j. when I got there they found the lift pump bad replace it and codes went away, drove back to Fl. then a week later I had to go to jersey again got to virgina an the codes came back p0251,p0370 drove to jersey park the truck , had to go back to Fl. so I flew back and back to jersey ,I started the truck ran fine about 50 miles later p0251,p0370 again , replace lift pump (again)pmb with 6ft and cooler, fuel filter , and I get a pint of fuel in 15 sec. is the injestion pump bad I read I lot about the sensor on top of the pump PLEASE HELP need to get back to florida

[More Power]

Welcome to the bulletin board.

P0251 Injection Pump Cam System
P0370 Timing Reference High Resolution

P0251 is due to a problem with the optical/electronic portion of the fuel injection pump.

P0370 is also produced when a problem exists in the optical/electronic portion of the fuel injection pump.

Though rarely the cause, a bubble in the fuel could distort the optical signal, and is mentioned in the GM service manuals as a possibility.

The standard rule (approach to solving problems) applies here when dealing with a problem fuel injection system.

1- Make sure plenty of clean commercial diesel fuel is in the tank.
2- Make sure the fuel filter is clean.
3- Make sure the electric fuel lift pump is generating fuel pressure.
4- Make sure you cannot identify any loose electrical connectors or abraded wiring associated with the fuel injection pump.
5- Make sure all of the above have been eliminated as a cause of this problem before spending any money on parts or labor.

The 6.5L Turbo Diesel Volumes I, II & II and the 6.2L/6.5L Diesel Troubleshooting & Repair Guide contain far more information. See more info here: http://www.thedieselpage.com/books.htm

[chevy6.5]

were is the best place to ck fuel pressure

[chevy6.5]

can it be ck. at the drain with the t on the front of the engine

[DmaxMaverick]

can it be ck. at the drain with the t on the front of the engine

That's as good a place as any. I use it. It works.

[More Power]

can it be ck. at the drain with the t on the front of the engine

Verifying pressure is pretty simple. If fuel flows out the drain line when the t-valve is opened, there's pressure. The exact pressure is less important than whether there "is" or isn't pressure.

The downside to opening the t-valve is that the engine will stall (airlock the injection pump) if the lift pump isn't generating pressure because air will be sucked into the drain line. A safer way to do it is to insert a fuel pressure gauge into the open end of the drain line before opening the t-valve.

Recovering from an airlocked fuel injection pump is sometimes easy and sometimes hard to solve.

Jim

[chevy6.5]

ck has pressure , cannot see any problems with wires , runs with the t open

[DmaxMaverick]

ck has pressure , cannot see any problems with wires , runs with the t open

With the Tee open, is it showing good fuel flow? It should flow at least a pint a minute with the engine idling. If it doesn't stall, and has no fuel flow with the Tee open, the line or valve may be blocked. As Jim said, it's much better to install a gage on the drain line and see what you actually have. At idle, it should maintain a steady 4-10 PSI.

[chevy6.5]

should I change the pump still have 0251,0370 driving me nuts (if it was a gas I could fix new to diesel) just got truck the truck is 1999 with 103,456 should I drop the tank or change the injection punp , I am new to diesel I drain the tank and put 10 gallon and 2cycle oil, drove it for 50 so milies still have codes , I I clear they come right back at start up , is there something I am missing

[More Power]

Once you've eliminated the possibilities listed here, the need to change the fuel injection pump looms large.

It appears there's a problem with the Optical Encoder Sensor (EOS). While a few intrepid souls have changed an EOS on their own, it's a risky situation with little guarrantee of success. For most people, I recommend a pump change - done by a well qualified tech using certified parts.

Jim

[chevy6.5]

Call chevy for new lines ,said N/A any more , any body know of aftermarket lines from tank to lift pump and return line from tank forward let me know please , mine are not leaking but showing a LOT of RUST may not last long:)