fuel injectors

[jinmared]

How do I tell if one of my injectors is bad? My tractor is getting blue smoke in the exhaust.
My Jinma 354 is a 2004 model with 254 hours on it.

 

[Bob Rooks]

Blue smoke is not from a bad injector, it's from burning oil. It's possible your piston rings haven't seated yet at only 254 hours. What type of oil are you using, and have you been changing it? Have you ever performed a lube oil analysis to check for fuel dilution?

 

[Ranch_Hand_Supp]

#1; How do I tell if one of my injectors is bad?

#2; My tractor is getting blue smoke in the exhaust.


#3; My Jinma 354 is a 2004 model with 254 hours on it.

#1; The best way is with a pop tester. Is it hard to start or don't run right?

#2; When ???? all the time, when you start it, when it is at idle, under load, when you give it throttle or when .......... ?

#3; With what engine?



Ronald
Ranch Hand Supply

 

[Turbo]

Piston ring seat with in the first 25-50 hour if they haven't seated in that time the cylinders have glassed and you would of been blowing smoke from day one.
I am sure that's not the case since you have 254 hr. and now your having the problem.
1. broken piston ring, stuck ring from carbon, or cylinder liner wore out
2. intake or exhaust valve guide clearance beyond limits.
3. to much oil in the sump.
differential compression test is your next step for diagnosing the problem.

when I had a bad injector will sound like some one throw in steel ball bearing in the cylinder and blow blue smoke.

 

[Bob Rooks]

Piston ring seat with in the first 25-50 hour if they haven't seated in that time the cylinders have glassed and you would of been blowing smoke from day one.
If the engine isn't broken in properly and run lightly loaded, then yes, the liners can become glazed, but this would not necessarily manifest until some time later.

1. broken piston ring, stuck ring from carbon, (Result from running lightly loaded) or cylinder liner wore out (Result from dribbling (bad) injector washing the oil film from the liner walls and diluting the oil decreasing viscosity). Note: You will not necessairily be able to detect fuel dilution by smelling the oil.

2. intake or exhaust valve guide clearance beyond limits. At low engine hours this can be attributable to fuel diluted engine oil, which has low lubricating qualities, or very dirty engine oil - accelerates wear.

3. to much oil in the sump.
differential compression test is your next step for diagnosing the problem. What is a "differential" compression test. Do you mean a leak down test?

when I had a bad injector will sound like some one throw in steel ball bearing in the cylinder and blow blue smoke. They will sound like that if they are leaking by and not holding pressure. However, that is not an indication of improper spray pattern or correct popping pressure.

123456

 

[jinmared]

I use RPM Delo 400 LE 15W-40 oil and I change it about every 50 hours.
The tractor starts well and runs good at all loads.
The air filter is clean
It smokes at the start up and does so when I am operating it , the more load on the engine the heavier the smoke (blue). I think I will have the oil tested by a company in Portland and see what that will show.
The tractor has run in the cold range(45 degrees C) since I have had it but I think that I will
fix the Tstat as others have done.

 

[Bob Rooks]

Getting your engine up to 80° - 82° C will make a big difference, and also may eliminate the smoking issue. Since the engine is running "cold", it has not reached thermal equilibrium - where components have expanded or "grown" to meet their design tolerances. It is also referred to loosely as "thermal efficiency".
There are a couple of real good labs in Portland. I use Stavely Services - great folks, and they will put a rush on it if you ask and email the results.

An afterthought: Using oil analysis as a maintenance tool can extend your oil change intervals by at least 200 hours. That's where I'm at now.

 

[daman1]

How do I tell if one of my injectors is bad?

Well to tell if there firing right but not familiar with your engine design you could start engine crack the injector feed line to the injector if it misses dies down that one is good move to the next one.

but a 2004 model with 254 hours on it i cant see burning oil especially since you say you change oil @ 50hrs,that engine should be like new yet .

 

[Turbo]

Bob
a differential pressure tester is a two gages tester with a fixed orifice in between the gages. one gage is the regulated pressure, the other is the cylinder pressure.
with the piston on TDC. apply a reg. press. of 80 lbs, and if the cylinder is bad lets say its showing 60 lbs or so, and your able to tell where the leak is, for example a bad exhaust valve will be heard out the tail pipe. rings will pressure the crank case.
the trick is holding the crank at TDC. and bing no spark plug hole, how can you inject air into the cylinder? though the fuel injector?
primarily I use on in aircraft cylinders, but I have used it on cars as well, take a lot of guess work out of cylinder diagnoses.

 

[Bob Rooks]

Turbo,
OK, I understand now. That is commonly referred to as a cylinder leak down test. I have made adapters out of glow plugs as well as injectors, which is what you would have to do to perform that test (as well as a standard compression test) on these Chinese engines. No test kit I've seen so far has adapters for these engines.