JD350 crawler slight miss

kilohertz

Member
Hi Guys,

Working on my JD350 (1969) dozer, and it has a slight miss that I am trying to diagnose before pulling things apart and ordering injectors etc. Could you fellows who know what Diesels sound like, when they have a little problem, let me know what you think this would be? Injectors, IP pump, simple valve adjustment needed etc,??

Thanks so much. I have linked this to a sound clip...hope it works.

Paul
JD350 audio clip
 
definitely works, I wish I could help with that one, don't know JD engines though, but its very audible, any puffs of smoke with it when it misfires ?

Cool you posted audio of it, that ought to help, I've often thought of doing the same thing well video too, but just figured I'd post back to let you know the link works fine, audio is loud and clear, good luck with the repair.
 
(quoted from post at 23:40:52 03/21/14) definitely works, I wish I could help with that one, don't know JD engines though, but its very audible, any puffs of smoke with it when it misfires ?

Cool you posted audio of it, that ought to help, I've often thought of doing the same thing well video too, but just figured I'd post back to let you know the link works fine, audio is loud and clear, good luck with the repair.

Hi Billy,

Thanks for the reply. Yes, it's an odd miss. No smoke at all when it misses. It took a bit to figure out the whole audio process...converting from my iPhone audio to MP3 then getting it onto my web server...then getting the link to work. I figured it would be much easier for people to hear it rather than me try to describe it.

Thanks again,

Paul
 
If you can get access to and borrow one of the infrared thermometers, it might show a slight temperature difference at the exhaust ports to indicate which cylinder is the problem. A lot of HVAC people use them. Or at worst Harbor Freight, but I am not sure you can find anything before you spend $30 at HF.
Bryce
 
That sounds like a generalized skip to me and not just specific to one cylinder. To be sure - take the exhaust manifold off. Very easy to do on a 350.
Then start it and look for any sign of smoke or noise in any specific exhaust port. You cannot tell with the manifold on. 350 use orifice-type pencil injectors and when they go bad they usually give symptoms similar to a fouled spark plug in a gas engine. Your engine sounds like it has a governor problem in the injection pump. I'd pull the timing window off and the top cover and look inside for any signs of debris. If you find anything other then diesel fuel - it's your problem. Post back here.
 
Good morning boys,

Thank you for the replies and guidance. I have one of those IR thermometers and will try that first. Good thinkin'. If that doesn't reveal anything then onto pulling the manifold and pursuing that avenue.

Agreed, it sounds random..and it wasn't like this 7 years ago when I bought it. Maybe just a little, but it has become worse. The fuel pump was supposedly new a few years before I bought the machine...but you never know. it's the Roosa Master DBGFC331-2DH. I've maybe put 500 hours on the machine. It's a 1969 350.

Cheers

Paul
 
It has a rotary-distributor pump and basically just
one set of high pressure plungers to power all the
cylinders. So unlike an inline pump that has an
injection pump for each cylinder, your pump has one
pump serving all the cylinders. The result is that
certain problems can make the engine run
"generally" bad instead of specific cylinders
skipping.
 
Thanks JD!

I started to work on it today...in a snow storm...and gave up when I couldn't get my pressure washer unstuck from the ice under the deck....but I did make a few more observations, which may or may not help.

1. Started cold and the smoke puffs were black, with the odd blue one in there...as it warmed up 30, seconds or so, the puffs went more bluish than black, then disappeared as it got warm. I also made a more detailed recording of various throttle positions.

If any of this info helps, please let me know. Once I get the pressure washer free, and the engine cleaned off, I can then start removing things like the manifold to test, and such. I also need to find the JD timing window for the IP, or is there a shadetree method of timing it?

Thanks again everybody!

Paul
JD350 audio clip part 2
 
The injection pump has an automatic timing advance that is supposed to advance the timing about 14 flywheel degrees as you rev the engine up. If it's sluggish or not working at all - it will really make it run lousy when you rev it but will not affect the way it idles at all. The plastic timing window allows you to check the advance with the engine running and adjust while it's running. There was a place on line selling them for $5 each but I might of bought up the last few of them. 60% off most prices posted. # 13366 at http://www.thompsondiesel.com/Stanadyne.htm
 
Hi JD et al.,

Okay great, thanks. Well here is what we woke up to this morning...looks like it might be a day or two before I get back to it. I'll find one of those timing windows in the meantime.

Cheers

Paul
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mvphoto5156.jpg
 
Doesn't look like your generator is generating any wind?? :lol:

It actually had 4" of snow on it before the sun hit it. Was going later in the day though. 2KW in 30KPH.

I ended up working on the winch (see separate thread) instead and now have another project. :roll:

Cheers
 
kilohertz
Pretty nice scenery in that spot you have there!
1. It sounds like poor fuel delivery to me too!
2. Just to eliminate one more thing, have the valves been adjusted recently?
Bring it up to temperature first, then adjust them all to specification, then see how you motor sounds. Sticking or tight intake valves can blow back into the intake, causing weird things to happen.
Please post back with your findings.
Brian
 
Hi Brian,

Thanks for the reply...yes it's pretty nice out here. No street lights in the valley and when it's dark, it's DARK.

No I haven't done the valves (ever) in about 500 hours of running. It's certainly on my list of things to do before spending money or pulling anything serious off. I also want to eliminate an air leak on the fuel line. I'm not sure how to do it...but was thinking of applying controlled low pressure, say 5 - 10 PSI with a hand tire pump and see how long it holds there. Probably just after the low pressure primary pump and will probably have to put a plug in the line just ahead of the IP. I don't know how much fuel would push past the IP with it not turning. Should be none, right?

I managed to get the pressure washer out of the ice, and am ready to wash the engine. I'll do that then pull the valve cover and adjust the valves :p

I'll keep you posted on my progress.

Cheers

Paul
 
HI Guys,

Today's update...pressure washed the whole machine, pulled off the valve cover and checked/adjusted the valves...everything was spot on, at worst, half turn off. Checked fuel lines, tightened all connections, again, no leaks or issues found. Bled the 2 filters, no air...drove it up the mountain for a 10 minute run and found under load in 3rd gear, somewhat bogged, when it missed, black smoke, just slightly as I had snow for a background. Running it back downhill, miss was still there but was less noticeable. Before I went on my little road trip I put 1/2 cup of each Varsol and ATF into the fuel tank, just to see if it may free anything up...of course, nothing. :roll:

Anyway, that's it. Going to order injectors, they seem to be everywhere now for around $30..not sure if the aftermarket ones are any good but we'll see.

JD, re: the cover on the IP, you said to pull the cover and look for mouse turds...those are the 3 slotted screws with the safety wire on one of them right? Think it has the low speed screw?? Will anything fly out or become dislodged that I need to be aware of? I'm working on a muddy wet driveway.

Cheers

Paul
 
Happy New Year!

Well, it's been almost a year, the snow is 3 feet deep and it's time to start working on the machine again. :roll:

So I have the injectors, but haven't changed them yet, and will when it warms up in March but am starting to do the simple things. Tried rotating the IP a little each way, not much difference, maybe a little better when I advanced it, but still skips.

John, you mentioned removing the top cover to see if there is any debris in there. Is that the cover with 3 screws that are held on with stainless safety wire?

One thing I noticed, while I was warming my hands in the exhaust stream, that when it misses, there is a noticeable strong "puff" associated with the skip. Not like the regular exhaust cycles that you can feel, it's a definite POP.

The machine runs fine and has been serving me well, I just want to fix this random skipping.

Thanks guys,
Paul
 
I think like Brian that you have a fuel problem,I would start by servicing the fuel system,start at the tank,make sure the fuel flow from the tank is not restricted,that the feed line from the tank to the feed pump is not drawing air,that the gauze in the feed pump is clean,replace the fuel filters,use a good quality anti gel,make sure the air cleaner is clean.
AJ
 
Oh great! Mouse turds! :cry:

Now what? JDemaris, as you suggested, I removed the top cover and found this, about 15-20 of them, they are crunchy and hard, like gravel, and very sharp and angular...WTH are these? I suctioned them all out and put it back together and of course it runs the same, but something is amiss. Did something let go, are these external contaminants??

AJ, yes, all of to your suggestions, thank you, which I did last year when I first started working on this.

mvphoto15283.jpg
 

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