How to check for a bad injector

[lmbrsn]

How can you test for a bad injector with out pulling them all out and having them rebuilt.
I will have the bad one rebuilt if it is the problem. It has a slight miss at full RPM.

Thanks Jim

 

[ScottFarm]

How old is the tractor? I had a 1988 Case 385 that would miss a little at PTO range, and just didn't want to get to full throttle. Ende up it was a tiny hole in the fuel line. Small enough I didn't see a leak. It ran fine at 1500-1800 RPM's, but it didn't want to get any higher than 1800 and it seemed like it was missing. Replaced the fuel line and all is good.

Scott

 

[lmbrsn]

It is a Koiti LB1914. It is mostly noticeable at higher RPM'S. and it seems to be lacking some power. No smoke of any kind out of the exhaust. It blubbers a little bit when you throttle back from high speed, like it is not spraying right. Trying to figure out which injector is bad.
Jim

 

[Hooked_on_HP]

Here are a couple of ideas that may help. Bring the tractor up to the rpm where it is running rough.Take a temp gun and check the temp on each cyl. where the exhaust manifold bolts to the head. The coldest one could be the culprit. If you don't have a temp gun, take a spray bottle with water and spray where the manifold meets the head and watch how fast the water evaporates. Or crack each injector and see which one makes the least difference in rpm's. Unless the cyl. is totally dead they can be hard to isolate.
Merry Christmas
Bill

 

[lmbrsn]

Thanks for the temp idea, I hadn't thought of that. I will try it when it stops raining.
Jim

 

[atgreene]

Have you replaced your fuel filter lately?

 

[Hooked_on_HP]

One more thought. Have the valves ever been adjusted.
Bill

 

[lmbrsn]

atgreene: Yes the filter has been changed.
Hooked_on_HP: I will check the valves again.
Thanks. Jim

 

[john_bud]

I would try

FPPF

or similar.

 

[fordman6442]

At a higher rpm how do you know it is an injector. I think about all you can do is get them all checked. If you could isolate the cyl then you could swap injectors from hole to hole. High rpm miss can be advance in pump, weak valve springs or pump timing.