B8200 Problems...D950 Help

[jhall30]

ok.... I have a 8200 HST- and was having problems with it missing on cylinder 1 (closest to the radiator) so I did a compression test and got the following results
cyl 1 = 350 dry 365 wet
cyl 2 = 350 dry 360 wet
cyl 3 = 400 dry 415 wet
after that I did a leak down test and all were good so I took the head off and had the head reworked with new springs/valves etc
after I installed the head back on I am still getting nothing on cylinder #1
I can take the exhaust manifold off (muffler)and it's cold as ice out of that #1 exhaust port
now I can give it some throttle and run it up to about 2200rpm's and #1 will try to fire but will not keep firing
I have triple checked the valve lash and all looks good there
have also checked to make sure there was no air in the line on the injector

any help or ideas would be greatly appreciated as I am scratching my head now

 

[kc8fbl]

Do you have a decompression lever on the tractor? I'm guessing that would affect all three cylinders though. I'm wondering if you have something in your injector nozzle? Have you tried to put any diesel additive in such as seafoam or the diesel 911?

Sounds like you have good fuel flow up to the injectors. I think I would try injectors. Hope this helps and it's an easy fix.

 

[Stumpy]

You're getting full compression on cylinder 1 though I'm not sure why 1 & 2 are so much lower than 3. The problem is probably with the injection system.

I assume you've bled the system a dozen times by now but are you seeing good fuel to injector #1? If you are I'd remove injector #1 and hook it back up so it will spray on the ground and see if you're getting a good pattern or anything at all out of it. It could be the fuel pump is moving fuel but isn't generating pressure from the cylinder #1 plunger for some reason. I think it's possible for the injector to get stuck shut too but I'm not sure.

 

[jhall30]

well today I tried to swap injectors and see if that would make any difference and it did not so I am back to the drawing board
this one's got me baffled for sure....not sure what to try next????

 

[Apogee]

I'd pull the injectors and injection pump and take them to an injection repair shop for testing and likely repair. At the very least, they will be able to verify the pump pressure as being correct. I'm guessing it's not and you have a problem with the #1 plunger. You might want to call to make sure your local injection shop can work on the Kubota (Zexel) pumps. Some have the equipment to do so and some don't. If they don't, they will likely know who to refer you to.

I'd bring in the injectors at the same time because they can test the spray patterns to make sure they are popping at the correct pressure. Might as well get them done while you're working on it.

Don't know who's around you, nor have I shopped for price. Nevertheless, here's a link if you want to do it by mail:

http://oregonfuelinjection.com/index.php?pid=65

Don't forget to order yourself new copper crush washers that sit under the injectors while you're at it.

Good luck,

Steve

 

[jhall30]

Hey Steve
Thanks for the advise on the pump....yeah that's my next move I suppose
although I have taken all the lines off and watched the pump cycle fuel as I turned the engine over it all looked good to me but who knows...it could be the pump???
I'm in NC so i'll start the search tomorrow for a place to get these parts tested

 

[jhall30]

Still haven't found a dealer around here to send the pump to get it checked

Have been poking around on the net trying to narrow it down a little more to see if anybody else has run into the same type problem and have come up with nothing????

I have went back through everything again just hoping I missed something but it still will not hit on #1 cyl
Could the pump timing be off for just that 1 cylinder?....I replaced the injector and it still runs the same
I would think it you advance or retard the pump timing it works for all 3 cylinders...or do the shims stack on either side on the pump?

 

[Apogee]

Hey Jayhall,

I think Stumpy nailed it when he mentioned that the #1 plunger is moving fuel but likely not generating pressure. I'm thinking the same thing.

The pump plungers are driven by a cam and you can't usually adjust timing on just one cylinder. The shims adjust all three cylinders at once. I do know they adjust the individual plungers to set the pressures, but as far as I know ,that's it.

I'm *guessing* that perhaps a piece of something got into the #1 plunger and scored the bore. I'm thinking perhaps a flake of rust from someplace (fuel pump) if it had been sitting. It's a shot in the dark, but it's pretty much the only thing that makes sense to me. Other than that, perhaps there's a problem with a lobe on the pump camshaft... Either way, it will need to come apart to find it.

For reference, look at the pics of the fuel pump from another thread and it'll make sense where the flake of rust might have come from:

http://www.orangetractortalks.com/forums/showpost.php?p=64601&postcount=12

I guess the only other idea would be if the metal line or the check valve on the top of the pump happens to be plugged, kinked or cracked (if cracked, I'd expect you'd have seen it though). However, I wouldn't expect the fuel volume to match the other cylinders if checked at the injector end. What I'm wondering is if you removed the lines from the pump or the injectors themselves when testing flow? It's unlikely it's the check valve because you'd have nothing, but it still couldn't hurt to take it off looking for crud. However, if you've only checked at the pump itself and not at the injector and there was junk in the line, that might be it. I'd certainly take it off and blow air through it... Removing the line is obvious, and the valve I'm referring to is the thingy that the metal line attaches to on the pump. It unscrews from the pump housing and you can check to see if it's plugged. I wouldn't recommend going any deeper into the pump though.

The other thing that I would second as it was mentioned above, is removing the injector, attaching it the line, cranking it and seeing if it is popping with a good spray pattern. Make sure you don't let it spray against your skin!!!!!! It is a quick and dirty way for you to check the pump pressure.

I wish I could help more, but I'm stumped.

Please keep us posted on what you find so we can all learn!

Steve

 

[jhall30]

Today I did a few things to troubleshoot this issue
first I took all the injector lines off and blew them out with air hose
took the barrels out of the pump to make sure there was no blockage and there wasn't so I put those back in and took the injectors out...hooked them up to the pump and spun the engine over ......all 3 injectors made a nice pattern of spray...all looked the same (spray wise) so now i'm wondering if it is a fuel issue??????????
i'm running out of options to check and troubleshoot
when I start the tractor and let it idle it just pours out the gray fuel smoke and the other two produce blackish smoke
when it warms up a little the smoking stops in 2 and 3 cylinder and dissipates some in cyl 1 ....when I wrap the throttle after it warms up I get black smoke out of 2 and 3 and gray un-burnt (I mean burn your eye's) gray smoke from #1
any more ideas are greatly appreciated
thanks Steve & Stumpy for all the help!!!

 

[Stumpy]

Yeah I'm stumped too. I would figure spray pattern to be a pretty good sign of injection pressure and if it is then all the signs say your motor should be working satisfactorily. If it was a fuel issue I'd expect all cylinders to malfunction not just #1. Has it been losing oil? I wonder if the stem seal on the intake valve is leaking. I'm grasping at straws here though.

 

[Apogee]

jhall,

Excellent that we have a good spray pattern! I presume you checked each injector hooked to it's appropriate pump port correct? Just want to make sure plunger #1 is developing good pressure. If so, at least we now know the pump and injector are working properly. That also rules out the pump camshaft so that's good.

Any chance that starting fluid has been used on this engine? I'm wondering if perhaps you have a cracked piston. I know you wrote that you compression checked it, but perhaps we should do it again as a double check...

Other thoughts would be either a cracked head or blown head gasket, but again one would expect to see low compression on a compression test.

Are you sure that you bled off the pressure on the compression gauge each time you tested? Mine both hold the pressure reading unless I manually bleed off the pressure between tests. Any chance that you overlooked doing that? I ask because both #1 and #2 have exactly the same pressure...

Last idea, which you also mentioned checking, would be if a valve was out of adjustment but I'm guessing they're fine.

Also, somebody else mentioned the compression release being out of adjustment...

Finally, only other thoughts that come to mind would be a bent pushrod, a flat camshaft or lifter (or both) on the #1 cylinder. You could check this with a dial indicator comparing the overall lift on both valves to the matching ones on a good cylinder without needing to take anything major apart.

There simply aren't many more options so I think it's time to start re-checking...

Does the engine have much blowby when running????

Please keep us posted on what you find.

Good luck,

Steve

 

[bandaidmd]

You taking your compression test thru the glow plug hole or the injector port? Maybe when your testing the hole is sealed but when the actual part is in place its letting compression escape. It dosn't take much loss on a compression ignition motor to prevent combustion? just my 2 cents

 

[jhall30]

So the latest is I talked to another Kubota service dept today and after a long conversation with the service manager...he is stumped to?????..told me to just put another motor in it
so I am hoping that someone see's all the post and has run into a similar problem and will be able share what they did to solve their problem

This is driving me crazy....there is no "logical" reason it should not be running fine on #1

 

[Apogee]

Bandaidmd might have nailed it. Perhaps you have a leaking crush washer under the #1 injector...

Any service manager that makes a statement like that is just trying to sell you VERY expensive parts. I know which dealership I wouldn't be going back to! What an idiot!

I'd be rechecking EVERYTHING. Somehow something's been missed...

I would definitely be rechecking the compression. Don't worry about the wet test, just do dry. See what you get and post back.

I'd also be ordering new copper washers for the injectors. Lastly, I'd also toss new glow plugs into it just in case the #1 plug is leaking somehow and you happen to be compression testing through the glow plug hole. If it was leaking, you wouldn't catch it with a compression test, and you'd be pulling your hair out - kind of like you are now doing...

Try swapping the #1 and #2 glow plugs and see if the miss also moves. Maybe the #1 glow plug has small crack in the tip and is venting out through the body of it.

Steve

 

[jhall30]

so I've been rechecking everything again for the oh 4th time or so
I have swapped glow plugs , injectors , almost everything and I have rechecked the valves and another compression test and leak down as well
one thing I did see different was the compression on #1 ....it is 345 now and was almost 400....something fishy going on in that cylinder...also now am getting about 25% leak down on that cylinder now...and I just replaced the head so that leads me to the bottom....I spoke to a Kubota tech last week and he suggested I put a couple of pump's of oil in the cylinder and try to crank it...he said if it starts firing for a little then it is more than likely stuck or a broke ring...well I did it...at this point in the game i'll try about anything
I put 2 pumps in the injector hole with my oil can and wala...it was firing on that cylinder...for a minute or so anyway
so....now I have to figure out what to do next?....I know these Kubota parts are very expensive
I may just try and find one used with low hours....I believe these D950's were used in a lot of different things

 

[Apogee]

jhall,

I think your recent test was consistent with your initial findings. Going back to your first post, you wrote you had 350 lbs on #1 and 400 on #3. Now you show 345 lbs which is pretty darn close.

I'd put a dial indicator on the valve train and compare #1 intake and exhaust lift to an adjacent cylinder. I'm wondering if you have a flat cam lobe or a bad lifter... It could cause a misfire like this and the compression would still be correct.

How much blow-by does it have when running?

 

[jhall30]

not to much blow by until it gets hot...after it warms up and I get it working there's quite a bit of smoke...no oil coming out of the breather tube but a good amount of smoke

 

[Apogee]

The smoke is likely because that cylinder isn't firing correctly. Some unburnt fuel may be washing past the rings into the crankcase and finding its way out the breather. Based on compression, it likely needs rings but they're not the show stopper that is going on here. I wouldn't worry about them. We need to find the gremlin that isn't letting that cylinder fire.

I guess the only other thing we haven't hit would be if ether was used on it. It tends to crack Kubota pistons, so maybe there is a hairline crack that opens up when it gets hot. Honestly, I doubt it though as you'd still see low compression on the cylinder.

I'm thinking valve train someplace since it's not fuel. It will be interesting to see if the lift is the same as one of the good cylinders.

You might also check the pushrods to make sure you don't have one that is bent. That would do it also because it would reduce the overall lift on the subject valve. You'd see it as reduced lift on the dial indicator similar to what you'd see with a flat cam lobe or bad lifter.

Any chance that when you had the head off that you noticed marks on the piston(s) from the valves hitting? Could happen if the motor was over-revved accidentally. All a valve would have to do is kiss that piston once and it could bend a pushrod...

Fingers crossed at this end!

Steve