Engine/Transmission (1994 - 1998) 94 2500 Injection Pump Question

[Rick Comenzo]

Limped home today after a 25 mile highway ride. Stalling/miss no power, and shut off. 331,000 miles on unopened engine 94 2500 2WD, regular cab, automatic. Fuel pressure a constant 25-30 PSI with mechanical gauge, and adjustable overflow valve. Mechanical lift pump and elbow hose replaced last year ,7500 miles ago. I changed fuel filter, (with new) cleaned checked strainer, all ok, bled filter manually with button on lift pump, no problem here. No unusual smoke or high temperatures as well. What is happening is, holding engine at 1500 RPM, no load, for perhaps a minute, suddenly a loud tapping noise and then stall out, with no immediare restart. Will restart after several tries, but the same will happen again. My question is time for a replacement injection pump,? Any help is graciously welcomed, as well as a source for a pump rebuild or replacement. Thank You. Rick.

 

[BigPapa]

suddenly a loud tapping noise and then stall out

Where's the tapping coming from? Have you checked your oil and coolant to see if you have any cross contamination?

 

[Rick Comenzo]

All OK there, tapping sound seems to be from the injection pump area. Thank you... ... ... Rick.

 

[MLee]

And the rubber fuel lines have been replaced? Sounds like lack of fuel, or air getting into the fuel lines. And You have a good seal on all fuel related connections.

 

[Rick Comenzo]

Thank you for the replies, Started truck this afternoon, a cooler day, ran with no load for 1/2 hour@ 1500 rpm, no problems, no stalling. Think this issue is temperature related. Will test drive and run locally. Alll fuel connections are tight, Engine started nearly instantly, but does seem to have a misfiring cylinder Rick.

 

[BigPapa]

Maybe he'll chime in here, but I've heard GAmes suggest to someone having pump issues to pour water on the pump when this happens to cool it down and see if it quits. You might PM him.

 

[GAmes]

There is a lot of documentation on the Cummins Forum about failed IPs in the '94-'96 trucks. There are several rebuilders on line, but my choice would be a local Bosch certified shop. The one in Austin has a lifetime warranty.

 

[trudydog]

Rick,

We had a similar tapping sound with temp during a recent 1800 mile road trip. I know you said you checked the fuel lines but just for a secondary QA mb put a wrench on em again. I got a 1/4 turn on one line and it solved the issue, I never thought that little twist of the wrench did anything but It did. I now make it part of a monthly routine to put a wrench on all lines and clamps;-)

 

[Rick Comenzo]

Thanks, will do a complete re check of all fittings and hoses. R

 

[KB0OU]

Have you still got the Fuel Heater on the Fuel Strainer Assembly? That may be leaking air. Remove the Heater, does not do any good anyway.

 

[bighammer]

You sure it's no the lift pump?

 

[Rick Comenzo]

Checked , tightened all fittings/hoses yesterday, found several hose clamps and fittings needing a turn, also replaced injectors, a long overdue chore. bled system, blew out lines from fuel tank forward ,runs smoother, will do a longer test drive today. The fuel heater is still in place, not connected, and the lift pump was changed less than 5000 miles ago. . But that does bring up a question... When pulling from a stop, my mechanical pressure gauge says 10-15 psi. Normally runs around 25-30 psi. but when the engine was shutting off the fuel pressure as normal. 25-30 psi??, Thank you for the replies. Rick.

 

[hsmith]

OFV getting weak?

 

[Rick Comenzo]

I don't believe so, adjustable overflow valve replaced last year, had it apart for a check yesterday,,,,,seems OK. Truck ran well today, will keep my fingers crossed. Thank You. Rick.