Hi everyone. Ok here goes. I’ve got an 08 kubota rtv900. All cylinders have good compression. Replaced all 3 injectors. It will start and run but only if the number 1 cylinder injector line is cracked open and spewing diesel fuel out. Once I close it, it dies. I think it might be an injection pump problem but how do I know for sure before paying 500.00 for a new one. Thanks
Running on 2 cylinders
- Thread starter Mikeheinkel
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85Hokie
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Equipment
BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
these replacements ................ OEM? or aftermarket?
Swap out #1 with #2 and see if the problem follows the injector or stays at #1
Swap out #1 with #2 and see if the problem follows the injector or stays at #1
Yes OEM. I’ve tried swapping them. No luck. It’s so weird, all 3 lines are getting fuel but when I close that one line it dies and it won’t start either unless I crack it back open
So what you are seeing is that back pressure on the line to #1 cylinder causes fuel to cut off to the other cylinders.
I do not know anything about injector pumps, but in a previous life did troubleshoot a lot of industrial control systems. Sure seems like something is wrong with the injector pump.
Would a normal running engine completely shut down if the line to one of the injectors was closed off? I would not think so. Maybe someone can answer this question and satisfy my intellectual curiosity.
Yeah I wonder if there’s a way to measure psi out of each port on the injection pump. I would just hate to order a new pump and that not be the problem
Assuming you did, what would it tell you (in addition to what you can deduce presently)?
Again, no expert, just thinking out loud.
But the fact that the engine quits, but does run when #1 line is open (so there is little back pressure) sure seems to indicate the pressure of the fuel at the other injectors must be dropping when #1 line is offering restriction to flow. And the injector pump is the source of that pressure.
Hopefully someone with actual knowledge of injector pumps will chime in.
I agree. Probably going to lead to a new injection pump. I did remove the pump and everything looked fine. All the spring pressures felt the same. Nothing looked out of the ordinary.
if you loosened it at the pump there is a possibility that the delivery valve turned in the pump; which means you get to either replace the pump or send it off for repair. Sorry to be the bearer of bad news.
never ever ever 'crack the lines loose' at the pump without knowing what you are doing it's too easy to mess up
never ever ever 'crack the lines loose' at the pump without knowing what you are doing it's too easy to mess up
I tried it at the injector to bleed the air out. Then tried it with the bleeder bolt on the pump. Then tried it at the pump line. Got the same results every time. But yeah you’re probably right, going to need a new pump. I can’t think of anything else it would be. Just wish I could test it for output pressure somehow