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.

 

[Ilikeurtractor]

The speed at which it cranks is independent of the fuel flow per crank. Even cranking slowly each injection will yield the same amount of fuel if things are working correctly. You can actually turn the engine over with a bar and socket on the front of the engine and you'll hear the injectors "popping" fuel at the time of injection (you have to listen carefully as it's not that loud - kind of makes a subtle, quick "vibration noise"). I'd focus on fuel getting to the pump at this point and make absolutely sure that is happening, even if it means running a new line to it, filling it with fuel while held vertical, bleeding it at the pump, and watching it go down as you crank the engine which it will if the pump is working correctly. Use some clear tubing for this. It certainly still could be the pump itself but I'd only look at that last.

 

[techwrtr2]

How about a temporary fuel supply to the pump, bypass everything? I did see fuel run from the bleeder but I really don't have method to verify flow. Project may have to wait a while longer, I'm going to add the power beyond kit to my JD since I have it and it's been on the shelf for years and use it to split wood. Or rent one. Catch up on everything else and ultimately pull the Beaver from its rather cramped home into the barn where I have good light and even a smattering of heat to keep my fingers movable.

 

[techwrtr2]

Stuck a new fuel filter on today. Opened the bleeder screw on the pump and saw bubbles as the filter filled and then eventually some fuel. No difference in the starting issue thought. I'm going to have to do some finagling to get a different fuel line in place, there's a screen covering the injector pump attached to the fan shroud.

 

[techwrtr2]

As an update to this old post... I have crap for compression on 1 cylinder and sort of better on the other. Ugh. Don't have time for this.

 

[techwrtr2]

And in other news... I really need to retest the compression. I decided today to address a minor problem which gave me a nagging feeling it might have major implications. In the course of trying to get the old beast to run, I'd replaced my fuel filter. Sometime after that, I discovered my entire tank of fuel drained out. Needless to say, I believe the old fuel lines the culprit so I replaced them and added fuel to test for leaks of which I found none. Things got interesting when I decided on a lark to try starting it. It cranked over much better, I don't understand why it would crank more readily when there's fuel versus not but it did. And then it started. The blankity blankity thing fired up and ran beautifully. I don't have much fuel in the tank so I shut it down after dancing around a little. A half hour later, I tried again. And it fired up again.

So I want to test compression with the engine warm to see what I get for results. But as long as the thing runs, I'm going to avoid going nuts with repairs I don't have the funds to complete.

 

[oliver28472]

Like!

 

[techwrtr2]

Kind of embarrassed that I didn't do this a long time ago. And also very glad I didn't buy an injection pump or tear the thing apart. Could have saved a lot of trouble and a little money. I think I'll end up doing an engine refresh soon, but I also think I can put it off for a bit. I hope.

 

[Ilikeurtractor]

...I don't understand why it would crank more readily when there's fuel versus not but it did.

Glad to hear the good results. My guess on the cranking when fuel is present is that it is burning somewhat while cranking therefore reducing some of the load on the starter and ultimately allowing the engine to crank faster (i.e. more power is being sent to the engine through the starter + burning fuel).

Technically, one should shut off the fuel supply valve or crack the injector lines when testing compression because these engines do supply a small amount of fuel even when the rack is in the "off" position which can causing readings to go a little higher than if no fuel is supplied.

 

[techwrtr2]

Your thoughts on why it cranks faster match my own. I'll plan to add a fuel shut off valve so when I test compression again, fuel will be cut.

 

[Jptech]

Glad to hear you got it running!!! I haven't had a chance to retest my compression, but maybe some of your luck will transfer over to me! I checked mine with the lines disconnected the last time. I'm going to check it again after I finish my Beer. I'll let you know what I get. -------------------John
:drink: