# Injectors Won't Fire



## F63 (Nov 2, 2008)

I'm working on a MF 35 with a Perkins. The engine just quit. I disconnected a fuel line going to an injector, cranked the engine and diesel came out. (No foam, no froth.) I pulled an injector, turned it upside down, reconnected the fuel line and cranked. No spray. I brought the injectors and the pump to a shop and everything tested fine. They suggested I make sure the return lines were clear. They were.
I put everything back together and the tractor started right up. It ran for about an hour and then just quit. I've repeated all above procedures with the same results: fuel everywhere it should be except coming out the injector nozzles.
I'm stumped and would appreciate any advice.


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## Upper5Percent (Jul 29, 2008)

Engine Starts and Stops
1.Air leak on the suction side of the system
2.Filter clogged
3.Fuel lines clogged or restricted
4.Water in fuel
5.Injection pump return fuel line or fittings restricted


My guess is Number 2...


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## F63 (Nov 2, 2008)

Thanks, Paul.
I've only got about 25 hours on the filters now, but it's worth replacing them and taking it from there.


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## Live Oak (Dec 22, 2003)

One other outside possibility. Check the tank vent to make sure it is open and clear. Mud Daubers can make nests in them or they can become obstructed for other reasons causing a tank vaccum after extended running which can cause the fuel flow to stop.


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## F63 (Nov 2, 2008)

I thought ya'll would appreciate a little follow-up. 
I changed the filters on that tractor, and/but, since I had the lines drained and needed a new prime anyway, I took every fuel line off, cleaned it really good, put it back together piece by everlovin' piece and followed the fuel through it. Everything checked out and the tractor started right up. I've since disked some rye into my upper field and made a few runs over to my neighbor's place, where I've got some junk stored ....
Everything points to the filters, of course, still a bit curious that they were impeding flow after 20 hours.
Thanks for the mud dauber tip, TF Admin. But there aren't any mad daubers in the tractor. You must've been thinking of my old Chevy. They usually build on the bottom of the alternator.
Thanks again, guys.


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## MFreund (May 2, 2008)

I was following along and wondered if you cut open the old filters and what you found inside? If you could would you?, I have always heard a scum (for lack of a better term) can grow in diesel in the heat of summer and wondered if this caused the filters to plug up.


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## F63 (Nov 2, 2008)

MFreund,
At your suggestion, I whacked the filters with a big hammer and leafed through the paper element. It was like new. I, too, have heard about the deisel dwelling bacteria. A hydro-carbon is a hydro-carbon, I guess.
I emptied the filters and all the lines into a clean bucket, and the fuel was clean, no water. This all remains a bit of a mystery.


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