Insite cylinder cutout test

[Bulljammer]

I watched in one of Rawze's videos how to do this test, he cuts out all but one cylinder, but my program only allows for a bank at a time. Is there a way to change this in Insite or is that specific to the CM870?

Also, could some point me towards a resource that describes what to look for on this test?

I found this in another forum, is it accurate?

"cut out each injector and watch the rpm, a good injector will drop in rpm then rise above the normal rpm. a bad injector will not drop or rise the rpm. the screen shot below shows normal rpm befor the injector is disabled. the next screen shows the injector being disabled, the red arrow shows the rpm drop then the rpm will rise. this is a good working injector, a bad one will not drop rpm or have a rpm rise."

Last week the tech did this and #2 hardly had any drop off, so we concluded that #2 injector was bad and replaced it. I just recheck it and same results with the brand new injector, hardly any drop in rpm when cutout. How can that be?

[Rawze]

Never had that problem. I am using Insite 7.6.2

What I look for is that all cylinders fire about the same, and that each one can keep the engine going the same way.

The test is only really valid if you first do an injector leak-down test first though. At the time i made the video, i did not mention it, because I didn't know this either, so that is why it is not mentioned in the video.

The proper method is to first do an injector leak down test, then do this test after it is all back together and no injectors are leaking.

[Bulljammer]

Just updated the post with more info Rawze.

[Rawze]

(03-25-2016 )Bulljammer Wrote:  Just updated the post with more info Rawze.

Sounds like the "other forum" is taking guesses. If an injector is bad, it will leak, or not fire a cylinder much at all, or continue to fire a cylinder when it is not supposed to. - If the leak-down passes, and each cylinder fires and runs the motor generally well, the injector is most likely good. If an injector was/is bad, it will leak, and/or the engine would die almost immediately, run rough etc. It sounds like someone wasted money on injector that may not have been bad. Did they even do an injector leak test first? -- I doubt it.

I have heard lots of bullshit stories where guys "claim to hear" subtle differences, like cutting out only one injector, listening for very subtle pinging or other differences, subtle rpm fluctuations etc. It is pure bullshit!. If there is not something VERY significant, and VERY noticeable, not subtle, then there is no evidence of a failing component. To replace parts just because there is a very slight fluctuation etc. is wasting money and blindly guessing hands down!.

I do not run my truck on "guessing" bullshit results. No one else should either.

If you got 6 injectors that are very old, 3 of them are now leaky and failing, -- A logical "guess" would be to conclude that your likely facing all 6 being worn out. -- Is that a guess -- sure,.. but a logical one that makes sense and has merit based on normal component wear and the laws of physics.

To blindly look for obscure subtleties in an engine, trying to compare already old, worn components with little or no merit is not a logical "guess". It would be normal for there to be differences, so the only thing that can be relied upon is significant differences, like finding an actual leaky component, or one that significantly does not perform well and causes significant engine problems. Anything less is generally a waste of time, and changing components based on such subtleties is pure guessing and will not likely produce results that warrant the component change.

Just my own Bullshit $0.02 cents worth on it any ways. My own truck breaks still 9 mpg all day long, and the engine is now surging at idle, runs a bit rough, etc. Are the actuators worn out -- Hell yes, they got 960,000 miles on them!. Are the injectors worn out? -- Hell yes, they got that many miles too!. Am I going to replace them? -- Not until I do my inframe, and even then, I do so reluctantly, but only because the engine is now surging at idle sometimes, and not because the components are old, or have subtle differences.

When there is clear cut evidence of a failing component, or one that will fail in "x" number of hours on my truck, I replace it before it becomes a problem. Otherwise, I run the damn thing down the road and not worry too much about it because that is in fact what its purpose is. To make me money and get every last ounce of component life I can before having to spend money on component replacement. In the mean time, I look for signs of failure or concern, but only take note of them until the evidence is clear enough for me to make a decision without having to "guess blindly" unless I have no other choice, and it is rendering my truck unreliable or un-profitable. - Even then, I will only replace something on a "guess" or "suspicion" if that component has lived well past its expected lifespan already, and there is no way to test it on another vehicle etc.. This way it is not a wasted expense.

[ashdan2010]

Agree 100%! I just replaced to leaky injectors this past weekend, did leak test again and injector cut out test. The 4 old injectors ran better then the 2 I replaced. Leak test is defiantly the way to go. BTW thanks for the videos on replacing injectors, made my weekend alot easier.

[Coco620]

Funny I showed my mechanic buddy a screen shot of the injector leak test tool on Rawze's vid and clearly he had no clue what it was & told me I waste too much time reading internet b.s.!! Lol

[Rawze]

(03-26-2016 )Coco620 Wrote:  Funny I showed my mechanic buddy a screen shot of the injector leak test tool on Rawze's vid and clearly he had no clue what it was & told me I waste too much time reading internet b.s.!! Lol

I like how we are all full of s%it, yet he does not even know a certified tool when he is starring at it. -- I think you just caught him with his foot in his mouth in a big way. That one tool alone has found so many rough idle and fuel mileage problems that other shops could not solve it is not even funny.

Keep the scoops of Internet bullshit from this site headed his way. Maybe someday he will learn how to work on an ISX properly!> I like being full of S^$T!.

[Coco620]

Lol he was p....d!! Told me to go find something to do .

[Rawze]

(03-26-2016 )Coco620 Wrote:  Lol he was p....d!! Told me to go find something to do .

I would highly encourage him to "read too much b.s." too. At least he can be up on the latest ideas and methods. -- Not doing so, only makes what he does, and his ideas antiquated very fast in this world full of open information.

BTW: You found something to do ... You educated yourself towards knowing more about what should be done to your truck/engine when others work on it.