heykw

My 98 12 valve is low on power the egt only get up to 700 or so and it seams to me that the truck is not getting enough fuel. I have a banks plate full forward and the smoke screw all of the way in and all I can get the truck to do is smoke just a small puff at take off and then it clears right up the waste gate is blocked and I am making around 25 psi of boost this seams low. I changed the fuel filter today and it was dirty and definitely in need of changing. When I was priming the truck with the little plunger on the side of the block I could hear what sounded like compressed air leaking out near the injection pump. I did not see any leaking fuel and was unable to find exactly wear the compressed air leaking noise was coming from help please I need more power.

turbos10

What you are hearing is fuel bypassing the return valve. Could be that the return valve spring is shot; can cause low fuel pressure in the pump.

heykw

I just looked at the passenger side of the head near the injectors and it appears that all of the injectors at the return line are leaking? Could this be the problem?

And wear is the return valve located is it an easy fix do you have a part # Thanks for your help.

turbos10

The return valve is located in the injection pump right where the return line comes out. It is on the engine side of the pump about 1/2 way up and is a banjo fitting. Sorry no part number, but a cummins dealer can get it if someone else does not have it. I would check fuel pressure before you start buying parts. You could temporarily plumb in an oil pressure gauge if you have a spare one.

Any leaks are not good, but I would not think a leak on the returns would cause low power. None the less, you need to get them fixed.

heykw

Thanks for the input, what should the fuel pressure be?

turbos10

Search this site and you can find it. I dont know off the top of my head.