78 450c won’t turn over but one revolution?

[Wgarner1414]

Ok guys need some ideas of what might be going on. I have a 78 450c track loader. Loader was running fine last year and I hooked the back hoe up and blew a hose. Changed the hose after sitting a few months and wouldn’t start up. Hot battery good connections but would only turn about one revolution and pull high current on battery cables. Put a new starter on last year that was still under warranty so I pulled it off. Bench tested and it sounded a little rough so I sent it back for replacement. Installed new starter today and it is still doing the same thing. I have bypassed the battery cables and hooked directly to the starter with jumper cables and still no luck. Any ideas what could be causing the engine not to turn over? Could it be vapor locked or something? Is it worth cracking injector lines and trying to turn it over? Any ideas would be greatly appreciated.

[Jim B]

Does it turn part of a revolution each time or does it not turn at all since that first time?

Was it setting outside? If so was the stack covered?

I doubt vapor lock. More likely is it has hydro locked from liquid ( rain or coolant) in a cylinder. Pulling the injectors will tell you if there is liquid in a cylinder. It might have rusted a cylinder up and bound up on rust.

[Wgarner1414]

Jim,

It will turn one revolution every time you try to start it. Loader has been outside and I did forget to put bucket over the stack at one time during the sit. I don’t know if it got rain in it before I realized I left it off.

[shinnery]

The next thing I would check is to loosen the oil pan drain plug to see if there is any water in the pan. When you just loosen the plug and NOT remove it water (if there is any) will be the first thing to try to drain out. If it got any water in the stack some could have gotten around the rings and to the bottom of the pan. Water is heavier than oil. Then try removing the injectors.

[NWJD fan]

No way you could have messed something up installing the new line on the backhoe and you have some kind of hydraulic lock up like if hydraulic quick connects are not done up properly?

[LeonardL]

No way you could have messed something up installing the new line on the backhoe and you have some kind of hydraulic lock up like if hydraulic quick connects are not done up properly?

That is exactly my thoughts as well. I would make darn sure the main feed lines to the backhoe are coupled together at the couplers. This has caused more starters to be replaced when all it was is hydraulics. If they aren't coupled together it will allow your motor to turn about one revolution and then stop.

[Wgarner1414]

Thanks for the input guys. I will check for water today as seems most likely. No mix up on hose it was on out rigger and was running when it happened. Just moved loader to current location and parked after that happened. Will update with findings.

[Wgarner1414]

Ok guys still no luck getting it to turn over like it should. It did turn over more than once a few times messing with it but slow and very labored. Using jumper cables directly to starter so no wiring issues to worry about. What I’ve done so far.

1. New battery
2 New Starter
3. Pulled drain plug no water in oil pan.
4. Pulled one injector. 3rd from front of machine. No water in cylinder. Don’t have puller others were stuck and didn’t want to damage them.
5. Removed back hoe and hooked loader lines back together.

Any more ideas?? This thing is driving me crazy.

[Jim B]

Check to see that the loader valves are in neutral. Does yours have a diverter valve that could be in the wrong position?

[Wgarner1414]

No diverter valve. Have moved all controls everything feels normal and returns to center. Think these are open center valves anyway right? I’m wondering if there might possibly be an issue with hydraulic pump causing it to load the engine. I can’t rem Er if mine has the disconnect or not. Think I’m going to look at that next.

[gregjo1948]

Sounds like what happens when too much starting fluid is used.

[Wgarner1414]

Gregjo

I would agree no starting fluid has been used. Won’t turn fast enough to warrant it lol. Only ever used starting fluid a few times since I’ve owned it when it had sat a long time in cold temps. So I don’t think that’s the problem

[77 Ford]

Have you tried pulling the hoses to the hoe and connecting them together to create the bypass? It really sounds like a hydraulic issue to me.

[Wgarner1414]

Yes those have been connected back together on loader. Back hoe has been removed.

[LeonardL]

I know it is a pain in the ass but take the hydraulic pump loose at the front of the engine. If you have a disconnect...( That still functions ) you can use it. But you need to eliminate what is or isn't the problem. You can pull the hydraulic pump and see if it cranks like it should. I know it is a lot of work but you will need to do this. If that doesn't help then you have something internal causing the hard cranking. Check that and then you can go from there.