Thread: Td5 cylinder balance readings

think of it as electronics doing what a harmonic balancer used to do.

This is part of what lets the TD5 put down power smoothly and its only really doable with the style of injectors that the TD5 is using... Its also good for economy as each pot when fired only fires enough to do the job it needs to do......

for those that HAVE to these can be used as a guide as to how effeciently your using the engine the smaller the variation the less fuel the engine is going to burn up.

if you get a couple of pots returning sane numbers and a couple returning huge fluctuations something is amiss.

if all pots vary about the same thats a good thing.

Angus, Don't be concerned, the cylinder balancing program is there to help you diagnose individual cylinder outputs/ efficiency at idle only. The parrameters are + or - 15 before it will log a fault, such as a misfire due to oil in the harness etc, so seeing 30's and even 50's above idle speed is inconsequential.
RAVE will help explain all of the ins and outs of the Lucas Td5 system, I get on screen help menus with Rovacom Lite, which is a really helpful feature. Knowing WHY readings are what they are is a very important part of using a diagnostic tool.

JC

The ecu detects from the crankshaft position sensor differences in the crankshaft acceleration caused by each cylinder and adjusts fueling to try to make the acceleration the same on all cylinders. When 1 is a lot different to the others then maybe there's an injector or compression abnormality.

I'd like to see the figures for mine when its in its vibration rev range to see if there's an injector less than perfect, although the injectors can't be too bad as no fault codes are recorded.

Originally Posted by Graeme

The ecu detects from the crankshaft position sensor differences in the crankshaft acceleration caused by each cylinder and adjusts fueling to try to make the acceleration the same on all cylinders. When 1 is a lot different to the others then maybe there's an injector or compression abnormality.

I'd like to see the figures for mine when its in its vibration rev range to see if there's an injector less than perfect, although the injectors can't be too bad as no fault codes are recorded.

Graeme, I have tried to use this feature to detect the very same thing, that is when I discovered that above idle, the system won't report imbalances and the processor is too slow to give actual real time info that is of any use

I thought I was onto something there too at the time

JC

Justin, thats a shame as I was hoping a problem might show-up and be able to fix this dreaded vibration.

Thanks guys. Im not trying to be one of those people that suspects problems with every little thing I pick up with the Nanocom, its more that I was interested as to why there is a difference.

Thanks for the explanations though. JC - sounds like the extra you pay for the Rovacom is worth it as you get better explanations on what the readings mean.

Angus

Originally Posted by justinc

Angus, Don't be concerned, the cylinder balancing program is there to help you diagnose individual cylinder outputs/ efficiency at idle only.
JC

hey Justin
I found this old thread and pulled it up like Angus i was also trying to find out why on all the cylinders it will spike all over the place
This cylinder balancing program is this on the nanocom or is it built into the ecu?
now if its in the nanocom could you guide me to it ,or do i know where it is already where it reads cylinder 1 : 3 cylinder 2: -2 ect ect
sorry if its a stupid question but i am new to nanocom and trying to learn what it does
thanks Kelvin