Duramax Balance rates

[Cowboy63b]

Where are my Dmax guys? I have questions about balance rates, what they mean, and how to identify a possible failing injector?

 

[ironman_gq]

They should be +- 4 to be in spec, I've always liked them to be under 2. Look up a DIY on the bottle test for return rates. The balance rate just tells you there's an issue but it isn't necessarily a failing injector, it could just be dirty. Lots of symptoms for a bad injector, poor idle, lope, poor mileage, white smoke when warmed up, raw fuel smell in exhaust, fuel in oil.

Balance rates are only measured at idle on a fully warmed up engine, think of them like fuel trims on a gas engine. It's a rolling computation of how much each injector varies in contribution (flow rate) from a base rate table. It's the most basic injector diagnostic and is nothing more than a starting point, more useful to monitor for trends or knowing when the injectors are getting near the end of their service life.

 

[Weasel]

how to clean, remove and ultra sound or can be done in vehicle? My edge has balance rates and was told mine are probably close to needing to be replaced. 110k on them so far.

 

[Elvis-n-texas]

Great write up on the diesel page.

Locating the older formulation GM cleaner is difficult, but basically you bypass the fuel input to the CP3, and allow the cleaner mixture to run out at idle, and a few mid rpm punches.

What year Duramax?
All LB7 generation injectors will fail.
I swapped mine a 100,000 miles.

It's a good weekend job, as there is maintenance that you should tackle at the same time.

New style, new construction Bosch injectors, and an EFILive 5 tune transformed my LB7.

 

[Weasel]

LBZ is mine

 

[ironman_gq]

LBZ is mine

Stock LBZ injectors hold up as well as any of the pre-LML injectors. There are DIY cleaning procedures that don't require the injectors to be removed. I would start with that and see what happens, high bio-diesel blends also do a pretty good job of cleaning the injectors, unfortunately they also clean out the fuel tank and lines at the same time and you will be changing fuel filters fairly often until it's all cleaned out.

 

[Elvis-n-texas]

How To: DIY - Injector cleaning

www.duramaxforum.com

This process improved my balance rates, but 20K later the 1st gen injector monster bit.

Post up your injector balance, fully warmed after a good drive in park and in drive.

Best of luck

 

[Cowboy63b]

Great write up on the diesel page.

Locating the older formulation GM cleaner is difficult, but basically you bypass the fuel input to the CP3, and allow the cleaner mixture to run out at idle, and a few mid rpm punches.

What year Duramax?
All LB7 generation injectors will fail.
I swapped mine a 100,000 miles.

It's a good weekend job, as there is maintenance that you should tackle at the same time.

New style, new construction Bosch injectors, and an EFILive 5 tune transformed my LB7.

Mine is an LMM.