S370 Beaver Injector Pump

[techwrtr2]

Finally got around to putting a new battery in the Beaver today as I've gotten tired of having to jump it when cold. To my chagrin, it doesn't want to start. Got great cranking speed thanks to the new battery, but no fire. It's actually behaving like it's out of fuel. It has a half tank.

I cracked the lines at the injectors and while things are damp, there was no appreciable fuel in the lines. I moved up stream to the fuel filter. Fuel in and out. I opened the bleeder valve on the injector pump, and fuel comes out there too.

This leads me to believe that I have an injector pump problem. Which does baffle me some since it has been running great other than the battery issue and it was running fine when I last parked it.

Before I dismantle it and try to either find a replacement pump or somebody to rebuild this one, anything else I might want to investigate or test?

This puts me in a bind because I have wood to split (lots of wood to split) and the Beaver is my power source for the splitter.

 

[Ilikeurtractor]

No idea here, but if it's your injector pump, it would be the first one I've ever heard of that was faulty to the point of not really pumping at all. Did you crank it over when the lines to the injectors were cracked at full rack setting?

 

[techwrtr2]

I had one cracked while cranking. I expected to have it forced out under some pressure and not just slightly wet line. I unhooked an injector line after cranking and there was no residual pressure which I'd expect. There also is nothing in the return line. I've never monitored that before so I don't have an idea of what should be there.

I have a hard time believing the pump as an issue myself since it's given absolutely no indication of being an issue up until now, and the fuel is fresh. Maybe a couple of months old at best. But since there is fuel up until the pump and apparently not after...

Not what I need right now.

 

[Ilikeurtractor]

One time I tested my pump for flow. At full rack setting each line put out about 2ml after 75 crankshaft revolutions or about 27 mm^3/rev. I just disconnected the lines going to the injectors, pulled the glow plugs (to prevent compression and subsequent battery drain/starter wear and tear) and cranked away into a graduated test tube. I was concerned each injector wasn't getting the same amount of fuel but they were within 0.2ml of each other after 75 cranks. Not sure if that is good or bad but I didn't pursue it further.

 

[techwrtr2]

Hmmm... seems like a reasonable test, even to confirm there is flow. Pull glow plugs and disconnect lines, perhaps direct into some tubing with initial interest to confirm any fuel flow. I can check volume later.

On the "bright" side, I found somebody who lists a replacement and has it in stock. Brand new. For only $550.

 

[techwrtr2]

And somebody who wants $450 used w/exchange.

Hopefully I can determine it is something else (cheaper).

 

[Ilikeurtractor]

I spent $500 to have mine rebuilt and it made no noticable difference in the way it performed despite it being diagnosed as "shot" by the rebuild shop. They claimed to have replaced all the internals.

 

[techwrtr2]

Which is a good reason to see if it pumps at all prior to buying anything. After that look for obvious things. I just wonder what I can look into or dismantle for cleaning maybe without special tools or knowledge.

 

[modifyit]

You didn't say you cranked the engine over with the injector lines cracked, so did you actually crank the engine for a reasonable length of time with those lines cracked. If I remember correctly, when I went through the same problem at one time, it took more cranking than I had expected to get fuel up to that point. Since you have fuel out of the filter, by opening the bleeder valve on the pump, I would expect a good flow of fuel after a very short time cranking the engine. I would also set it at full throttle while cranking. Just my two cents worth.

 

[techwrtr2]

Finally got around to checking for fuel flow. Almost nothing. Forward line gets some after substantial cranking, rear got some dribbles. I also realized that it slows cranking after a few cranks and seems labored after that. I believe it has started with that slow a crank speed in the past so I'm reasonably certain that isn't the problem. However I also don't recall it ever having that kind of an issue. Concerned I might have something more significant going on. When I first realized this was happening, I made sure the clutch was disengaged in the off chance something there was the problem, no effect of course. I think I'm going to have to drag it into the barn where I have better light and can have heat.

For the record, battery and starter are recent (very recent). I checked/cleaned cables and looked for any voltage drop, none. From the negative battery terminal to the block I have like .1ohm of resistance. Haven't changed cables yet.

Still I would think I'd see more fuel at that crank speed.