Balance rates and injector health

'strokeThis_'07

'strokeThis_'07

New member
What's everyone seeing in terms of bad injectors? I have #4 at 3.9, #2 was in the 2.8-3.2 range, and everything else was about 1.2 or less. Have we established a cutoff point, say anything over 3 needs replaced or something like that?


Truck has been hard starting occasionally, little puff of white, but lastnight seemed dead in one cylinder upon startup but started running ok after 15 seconds or so.

Haven't seen much discussion on balance rates, unless I've missed it
 
Anything at or over 3 is gambling from what I have seen. Usually end up replacing them and problems were solved.
 
Here is what my balance rates looked like.

I was having the same issues as you. White/blue smoke at start up with about 3-5 seconds of rough idle.

PhotoApr2573642PM.jpg


From what I was told, + means the ECM is calling for that injector to spray more fuel and the - means the ECM is cutting fuel.

See my ECM is desperately trying to fire #3 while cutting fuel to #5 to balance the engine.

Sounds like its time for some injectors.
 
All six of mine are negative?

Edit: guess not. I snapped a pic of my monitoring with my phone when I initially suspected something was up a couple weeks ago; cyl #1 was 1.9, #2 was 0.7, #3 was 0.7, #4 -3, #5 0.7, and #6 -1. Today they all looked to be higher values across the board
 
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So does the balance rate number go by firing order?

Say I have a high rate on BALRCYL5 +2.9, would that then be the second hole back from the front 1,2,3,4,5,6

Since the firing order is 1,5,3,6,2,4? Or is this jus overthinkin?
 
No, cylinders are 1-6 from front to back. I haven't played with EFI, but with a Duramax the balance rates are only available at idl; they are not flow rates and are used to create a smooth idle. I know GM claims anything + or - 5.5 is a faulty injector. I don't like to see anything over + or - 4.
 
If you have the time I would send them in to be tested, EFI does not consider return rates, low compression, bad valves etc. If they all test good do a compression check ASAP. I have been through this with my 06 cummins, lost rings in # 1 and #6.
 
I have a friend at idle his rates are great, put his in gear and #3 and 4 go to -3.9 and +4.0 take it out and they go right back to like .09, does this mean they are on the wat out?

Strokethis is yours ar idle or in gear?
 
I wouldnt worry about those numbers in drive, foot on brake. I have checked a couple of cummins now and they are about the same..
 
So does this look like I have 2 injectors on the way out? BALRCYL3 and BALRCYL6. Both hover in the 3-4mm^3 range with the truck in park at idle. Truck isn't any harder to start.

Screen1.JPG


Screen2.JPG
 
youngun said:
Did you have to do anything with your injectors yet? What miles or engine hrs are you at now?

Thanks
Click to expand...

I haven't replaced them yet. I'll probably order some new ones up and when they come in, send these off to be tested

Tobin said:
So does this look like I have 2 injectors on the way out? BALRCYL3 and BALRCYL6. Both hover in the 3-4mm^3 range with the truck in park at idle. Truck isn't any harder to start.
Click to expand...

I was told around 4, time to start looking at replacing them.
 
Any idea what is going bad in them? Mechanical or electrical?

I would like to really get them tested to see the difference they are flowing and see if it matches up with what the data log is saying.

Tobin
 
It's been over a month since I talked to Harvey, but IIRC it's mechanical, too much wear or something. Injectors are still a black art for me so not real sure.

The balance rates are the ECM trying to equalize flow though I believe.

Hopefully I'm not regurgitating crap and misinformation:eek:
 
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good to know a little more about what i have been seeing. we were concerned with my #2 being a little bit out, but i guess i need not worry...

20121124_154338.jpg
 
Looks like #2 is stronger than the rest as it is cutting fuel from that injector. Looks good across the board though.

Tobin
 
See one of mine is at +3.8 at idle and all the others are less than 1. But as soon as i give it gas it drops down below 1 and stays there. My truck starts perfect, idles great, smokes for about 3-5sec on startup and ZERO smoke while driving. Doesnt seem like my injector could be that bad as i have no signs of it.

Heres my numbers at idle
1. +0.9
2. -0.6
3 -0.2
4. +0.4
5. +3.8
6. -0.2

I take it all 6 injectors should be working together at 0.0 to deliver the commanded idle fuel? is the efiLive injector balance rates actually meant to tell when an injector is going south?? id really like to make it through the winter with what i have
 
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