Insite cylinder cutout test

[Coco620]

Yes I have learned alot & thank you Rawze & the other good guys on the forum hope the gentleman that started this post finds his problem , Good day

[Bulljammer]

(03-25-2016 )Rawze Wrote:  

(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.

LOL, now I should have expected the RR (Rawze Rant) on a Friday night, walked right into that one. :tire:

So I did do the leak down test myself before I started using this guy about a month ago, no issues there. Just curious why 5 cylinders react the same way, when you turn them off one by one the engine stumbles a bit and then comes back up to idle, but when you turn off #2, the new injector, there is no noticeable difference? (It did this before replacement too)

Also, Insite will let me turn off a bank at a time, one at a time, but not "5 at a time". ???

[Hedley]

move the Injector to a different cylinder and see if the nag follows the Injector.

[Bulljammer]

So are you saying Rawze that this is not correct?

"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."

If it is not correct then why do five cylinders respond similarly and one doesn't? I trying to understand why the cylinders are responding the way they are and its frustrating that I can't shut off all but one cylinder on Insite!

[Rawze]

That statement comes form a pick-up truck forum and the guy is referring to a 6.7 litre dodge pickup truck engine!. Those things are not even wet-sleeve engines!. Besides that I STILL THINK IT IS UTTER BULLSHIT! -- FIRE THE ENGINE ON EACH INJECTOR ONE AT A TIME TO ENSURE THEY ARE OPERATING WELL!


A CLASS-8 ENGINE HAS A CORRECTIVE IDLE GOVERNER. -- A 6.7 LITRE ENGINE DOES NOT! -- They do not even respond the same when there is a misfire.

- You should also get with someone who has a known good working copy of Insite to do a proper test on the injectors. Listening to subtleties by cutting out only one at a time is almost always completely useless and leads you to believe in ghosts. i cannot count the number of times I have heard mechanics say shi#t like that, only to find the actual problems later, after the truck owner wasted a lot of money. An ISX is NOT a redneck pick-up truck engine!.



I said my peace, I am not about to perpetuate those kinds of statements. It leads people who do not know any better down a path chasing ghosts and wasting money.


I had one once that would not run for crap on cylinder #2. It would even stall the engine sometimes when firing it on only that injector. All other cylinders ran and fired great otherwise. We swapped the injector into number 4, and guess what! -- Number 2 still ran like crap!. It was wear in the valve seat/head that caused it. The guy just kept driving it like that for another few months, even though he was warned that it could come apart at any time. He eventually had to replace the head because his fuel mileage kept going down more and more.

[Bulljammer]

(03-27-2016 )Rawze Wrote:  I had one once that would not run for crap on cylinder #2. It would even stall the engine sometimes when firing it on only that injector. All other cylinders ran and fired great otherwise. We swapped the injector into number 4, and guess what! -- Number 2 still ran like crap!. It was wear in the valve seat/head that caused it. The guy just kept driving it like that for another few months, even though he was warned that it could come apart at any time. He eventually had to replace the head because his fuel mileage kept going down more and more.

I talked to the mechanic this morning and let him know that the cylinder is reacting the same way it was before we put the new injector in. His thought was that it could be a compression problem or the actuator. So is he going down a false road or is that possible? I am so discourage from one thing after another.

[snailexpress]

(03-28-2016 )Bulljammer Wrote:  

(03-27-2016 )Rawze Wrote:  I had one once that would not run for crap on cylinder #2. It would even stall the engine sometimes when firing it on only that injector. All other cylinders ran and fired great otherwise. We swapped the injector into number 4, and guess what! -- Number 2 still ran like crap!. It was wear in the valve seat/head that caused it. The guy just kept driving it like that for another few months, even though he was warned that it could come apart at any time. He eventually had to replace the head because his fuel mileage kept going down more and more.

I talked to the mechanic this morning and let him know that the cylinder is reacting the same way it was before we put the new injector in. His thought was that it could be a compression problem or the actuator. So is he going down a false road or is that possible? I am so discourage from one thing after another.

Bad actuator will affect 3 cylinders. Ask your mechanic to remove intake manifold an bare engine in quiet environment. Hissing sound from intake or exhaust at the cylinder top point means bad valves.
Rawze has my valve burnt intake valve picture. It was exactly same symptoms you have.

[Unilevers]

i think you have a cylinder problem personally. has a cylinder leakdown been done? has the valve stem height been checked for consistency?