In vehicle injector flow testing

[JoshH]

I just had a thought. What do you guys think of checking injector flow balance by turning up the fuel pressure with the DVT function of the scan tool and checking balance rates? Good, bad, doesn't matter?

 

[TrentNell]

good question ! , hope this isnt a stupid question but how does the computer even measure balance rates to begin with ?

 

[JoshH]

The way I understand it, it senses if the RPM changes on each cylinder's power stroke. If it speeds up on an individual cylinder (as in too much fuel), the balance rate will be negative. If it slows down (as in not enough fuel), the balance rate will be positive. So in theory, if you had an injector that wasn't flowing as much as another one, it would have a positive number on the balance rate. I would imagine it would be exaggerated by increasing the rail pressure if it was an injector flow problem causing the balance rates to be off.

 

[IdahoRob]

Anytime pressure is changed at idle, It changes the balance rates.

So take a certain duration and change the pressure, the balance rates change.

Could be a good idea if you are wondering about a stock engine and keep the pressure the same, but Josh, you'll not need to worry about things like that.