Hello, I’ve been through just about every related post on 955k starting issues and am not sure what the pursue next. A couple months ago it was running strong then all of a sudden puffed some black smoke and slowly died. I suspect it could have been bad fuel. Couldn’t get it to start back. So far I’ve drained the tank and changed all filters. Changed out the transfer pump and all injectors. The injectors were full of junk when I swapped those out. I’m pretty sure I’ve got all the air out of the system. But I’m noticing I’m not getting much pressure at the injector line when I crank it and crack the injector lines but there seems to be plenty of volume. Any suggestions on where to go next? thanks
Did you change air cleaner and precleaner.
I checked the air filter and precleaner, both are nearly new.
We bought a 955 many years pass with brinth new motor with new big air filter and small air filter was like new the motor was starting but not easy and was smoking and maybe 30hours working the motor died and the probleme was the small air filter you could removed the 2 air filter and try to start with no air filter now am going to slepped.
I wish EVERY diagnostic thread started with.. REMOVE THE AIR CLEANERS.. I can’t count the number of times I’ve made a service call for a “NO START” condition, only to find the air filters packed full of crud.. I take’m out, throw them on the ground and watch a dust cloud like I let off a nuke.!! Lol Then of course comes the 30 minutes of bleeding the air out of the system..
I was assuming it was fuel related since I’m not getting any kind of white smoke while cranking. Previously when I bled the air out the fuel system the fuel when cracking the injectors lines would shoot out 6–7 inches when cranking now it’s more of a dribble out of each of the lines. I’ll try taking the pre-cleaner and air filter out and report back. Thanks
If you have no white smoke when you starting with trottle on or off with the fuel tank cop loosed and if you are missing fuel you could disconnect the rear fuel line from the tank if you have full fuel and if fuel is oké disconnect the front fuel line and put air in if the line is plugged
Fuel flow may be stopped up in the tank. Blow compressed air back through the supply line.
I’m getting good fuel flow when unscrewing the bleeder valve on top of the secondary filter housing. Seems to be getting good flow up to the injectors. The fuel doesn’t seem to be building much pressure in both the throttle off or on position. Are there any tell tell signs the injection pump has failed ? I’m gonna try removing the air filter to rule that out when weather permits.
Does your machine have a lift kickoff that could be engaged? I drove my former neighbors 955K a couple times and it wouldn't start 1 time because the loader valve was engaged.
You have to have oil pressure on some models before your injection pump will allow any fuel injection pressure for starting. There is a fuel stop that has to be overcome by oil pressure in the injector pump. Have you got good oil pressure when cranking over?
I’m getting around 60-70 psi on the oil gauge when cranking.
You do not have proper fuel flow if that's all you're getting. Which injector pump do you have on there, or what is the serial number of the machine? If the flow is restricted, it could be air locked. That's what it sounds like to me. Did you look for an inline fuel filter between the tank and the lift pump that could be plugged?
The serial number is 71J3060.
OK, that is the Japanese built equivalent of the USA made 85J1-4672 version. Should have the D330T engine.
Yes it has a D330T in it from what I can tell.
OK, first thing I can think of after looking at an 85J model online is the primer pump...they're notorious for sucking air. The o-rings inside them get worn out and air can be allowed in. You can rebuild them easily. Have you pumped it up with the primer pump? Does it pump up and get really hard to pump or does it bypass when you do it?
The one I looked at has the scroll type injection pump, above.
I actually just put a primer pump back on it. Someone who owned it previously took the pump and lines off and plugged the holes. I may have some air trapped in it somewhere because it never really gets firm.
Yes looks identical to the picture you posted.
Pretty sure that's your issue. You can unscrew the handle in place and the replaceable o-rings are on the stem. If you don't have a parts book, you need one. You should be able to get any part you need from your local Cat dealer, but you need to have the part number for them because they can't look it up in their computer system more than likely. Here's one on Ebay:
Hi d9gdon, The primer pump I put on it is brand new. I did notice when pulling out on handle the action isn’t as smooth as when pushing the handle in.
A restricted fuel flow will not allow it to prime either though.
Update: So after further digging into things it appeared the fuel rack was stuck in the off position. I took the injection pump and governor off as an assembly. Opened up the governor and and freed up the rack. The rack seems to be moving freely until it sits for a few days and then won’t move from the fuel off position unless I give the rack a little tap from the side that mounts to the accessory drive. Is the movement dependent on oil pressure and should expect normal operation when I reinstall the pump? Any tips for getting the injection pump to line back up with the offset tang on the accessory driveshaft? I attempted to put it back on and wasn’t able to get them aligned. My next step is to set the engine to TDC and try again.