Oil & Fuel diagnose injector pump

Abe460 · Feb 11, 2011

Hello,

Just wanted to ask if anyone could explain how to diagnose a possible injector pump issue. I have not tried to bleed the lines yet, will do that in the morning. I cracked an output line and it pulsed out some drops. What should the fuel flow look like with an open line off the pump? Already replaced the lift pump last year. I would like to have some knowledge going in...just in case I do get the lines bled and the problem persists.

I have a 2004 MF 471, it's a tier 2 model. It has run fine for the last year with only about 15 hours total. I ran it today for about an hour and shut it down to get some things ready to move. It would not start after that. It's done the same thing before once, I just waited a few minutes and it cranked right up.
This time I'm not so lucky.

Thanks for your time.
Abe

6sunset6 · Feb 11, 2011

Kind of hard to tell, not enough info. However I will tell you my experience with a MF 30e Perkins 3 cyl . 3 lift pumps over 6-7 years. You should get a good stream out of the bleed port on the side of the injection pump when cracking the engine on start. I finally got fed up with the mechanical lift pump and put in an electric in line. Plated off the port on the engine where the mechanical lift pump went. The psi delivery of the electric pump is a little more than the mechanical. I think I had a leak in the suction side of the lift pump which I found later. That may have been the original problem all along. But it starts and runs like brand new with the electric lift pump so I am leaving it in. The electric lift pump wanted a prefilter and I put an in line ahead of it. The original engine fuel filter is still in place downstream of the lift pump and recircs after the injection pump.
Don't know if this helps . Kind of basic knowledge though.

Abe460 · Feb 11, 2011

Thanks

The factory lift pump is electric. I didn't have time to check the flow from it, but would hope it's ok being I changed it a year ago.

I can't find the "bleed screw/port" on the injection pump. I looked in the book and didn't find anything. The manual does show a pressure, but I don't have any gauges to read it. I just need a slight description, so any info can help when I get to working on it. How much should you open the injector output to test the flow? I only turned it about 1/4 to 1/2 turn.