I get sporadic RPM readings whenever datalogging. Like it will jump up and down between each reading.
I remember reading somewhere that the stock RPM sensors aren’t accurate enough for datalogging. Does anyone know a good replacement? The RPM sensor is in the distributor, ain’t it?
bump for the mans question.
Anybody?!?
Think about what you just said. If the “RPM sensor” AKA distreibutor assembly, isn’t accurate enough to datalog, then it sure as hell isn’t accurate enough to run the engine properly.
If your RPM is sporadic, then your settings are probably incorrect, you are running a different DL protocol than what you DL software is expecting, etc.
You might want to include details when you ask a question like this.
What data logging software are you using, and how are you interpreting the RPM signal?
yea, i’ve spoken with a couple people on this and now realize there is no RPM sensor. I thought I’d read that you could switch sensors to get a cleaner signal to fix this…so that confused me - i realize it’s something else now.
I’m really just getting the feel for this and testing it out right now before my new build goes in. I’m just putting the log into excel to look at it and graph some indicators - RPM, speed, accel, TRQ/HP (from calculations). Datalogging with ECUcontrol using a bin from crome. The RPM readings are about accurate, they just fluctuate considerably. It’ll go up and down over over a few samples although the car isn’t stuttering at all.
I’ve played a bit with the poll time thinking that might have something to do with it, but haven’t had any luck. There don’t seem to be any other relevant settings. Does anyone have a recommended poll time?
Here’s a graph that shows RPM over time. Note the speedo also fluctuates. What’s up with that? Interference? That should be smoother to tune from right? Notice that I took about 650 samples from the bottom to the top of 3rd gear…Is that good? Unfortunately I need to fix my datalogging header/cable before testing again.
I doubt that a fluctuation of 100RPM over a second would make the engine run improperly. A 100RPM difference on the fuel and timing maps isn’t significant enough to stop the engine from running properly. Sure, it could harm performance - but it’ll still run alright.
