Which is cylinder #1

[jewing3227]

According to the VCM Suite balance rate scanner, I had a injector acting up in cylinder #5 and the scanner showed it being a +4. Truck didn't white smoke or run rough at all but figured I'd play it safe. Installed a new injector in #5 and started the truck. The rates did not change for that cylinder. Shut the truck off and double checked to make sure connector tube was ok. After starting it back up, now cylinder #2 jumped to -3.6. And was originally -.7.

For clarification, when you are viewing Injector balance rates with the vcm suite is cylinder #1 next to the radiator or back by the firewall. I've heard EFI Live puts #1 back by firewall. Maybe someone from HP Tuner support can chime in to clear this up.

Also for a piece of mind.......exactly how accurate is the balance rate it is showing? I feel like I'm doing all this for nothing for some reason. Just trying to be proactive based of what the scanner is reading. Something is definitely wierd, truck starrs, idles, runs really well

Thanks

[InlineSix]

Companion cylinder performance can and will effect balance rate. Without replacing the entire set of injectors on a common rail injection system one never know what to expect. I seriously doubt the software switches cylinder location. As a 20 yr diesel tech I've experienced quite the variety of diagnostic equipment and tuning/scanning software and have never found one that switches cylinder location. Some have reported EFILive to switch cylinder locations and I've experienced scenarios where I thought the same was true but after deeper investigation found cylinder location to be correct.

[jewing3227]

Companion cylinder performance can and will effect balance rate. Without replacing the entire set of injectors on a common rail injection system one never know what to expect. I seriously doubt the software switches cylinder location. As a 20 yr diesel tech I've experienced quite the variety of diagnostic equipment and tuning/scanning software and have never found one that switches cylinder location. Some have reported EFILive to switch cylinder locations and I've experienced scenarios where I thought the same was true but after deeper investigation found cylinder location to be correct.

I believe what you have to say here. I've heard talk about the companion cylinder but not alot on what effects either positive or negative that it may have. I swapped a good known injector to what I thought was a bad one. The supposedly bad injector went from a -3.6 to. +4 but then settled to +2 and the good injector from cylinder 2 that was +.7 went to +4. I've decided to stop where I'm at and drive the truck until it runs rough, takes longer than normal to start, or white smokes normaly. I'll do like others have and run ATF and 2 stroke oil occasionally and let it be. If not careful I believe one can "wear them self out" with what seems to be a problem but really isnt.

[InlineSix]

The ecm senses crankshaft speed fluctuations between the pulses off the crankshaft tone ring and uses that to change injector balance to smooth the rpm at idle.
What's so dangerous is that past idle the balancing effect is not possible and any fuel deliver imbalance is magnified as rail pressure increases.
What seems to be a small imbalance at idle can quickly turn into a piston melter at higher rpm.

[jewing3227]

So based off your experience and my input on this so far, what do you make of it. I just find it strange how a good known injector goes south just by swapping spots. I've also took a thermal gun and shot cylinder Temps at the manifold and their all consistant. Starts right up and No smoke on start up, idles smooth as one could expect from a cummins. I'm trying to be as proactive as possible here but feel I'm running in circles. I'm thinking based off what I already know versus what I have tried, like mentioned before, 6 new injectors who be the logical next step if anything changes.

[muz79]

A bit of light reading for you. Hope I haven't muddied the waters!

http://www.thetruckstop.us/forum/thr...e-rates.41579/

[jewing3227]

A bit of light reading for you. Hope I haven't muddied the waters!

http://www.thetruckstop.us/forum/thr...e-rates.41579/

I seen this post a few weeks back and didn't read it due to it concerning the duramax. I did read it this time and according to it, if you have anything beside a stock tune loaded while checking it can throw the readings off. Hell, just thinking about what this guy is saying.......just because the rates are what they are doesn't mean anything bad will happen.......according to him it is a factor to consider.

I, unfortunately, look to make everything I am involved it to be the best it can be (aka Anal or OCD) I believe I will take a step back and just drive the truck for awhile and just be aware of any white smoke, lose of power, rough idle, or hard start conditions.

Thanks for any and all participation in this post!


By the way, support emailed me back and said the numbering order of the rates is per Cummins numbers......#1 closest to radiator and #6 back by the firewall