ECMlink Why does my rpm and speed go up and down on a wot pull

[DJ23GSX]

Real simple question here. I've noticed that in most of my logs my rpm and speed are not smooth at all and bounce up and down on a wot pull. I know this is not normal as I've been looking at other peoples logs for a long time trying to educate myself before actually getting link. Is this a computer issue, mechanical issuer or a setting in link I'm overlooking? The laptop I use for link should be plenty powerful enough to run link (Toshiba U405-S2856)

 

[Chumpaumpalumpa]

are you getting enough fuel?

 

[DJ23GSX]

are you getting enough fuel?

I have plenty of fuel. Afr's on the wideband gauge are in mid to upper 10's. Those don't match the PLX in the datalog either but we'll leave that for another day . I actually had to lean out the mixture in order to get rid of knock from the previous pull.

 

[Chumpaumpalumpa]

Hmm maybe throttle position sensor or maf has gone a bit wonky I had a similar problem n I checked the maf n it was slightly unplugged on one side.... Unplugged it blew it off plugged it in and it was fine... Gotta chase down those gremlins before u can really diagnose what's happening

 

[henrysan]

I noticed my RPM and Speed also do this is my logs, but never thought much of it. maybe 1G have lower resolution/refresh or something compared to 2g? It seems most 2g logs i look at have smooth values.

 

[Chumpaumpalumpa]

very possible..... if the car accelerates smoothly its probably a reading issue of some sort

 

[DJ23GSX]

I noticed my RPM and Speed also do this is my logs, but never thought much of it. maybe 1G have lower resolution/refresh or something compared to 2g? It seems most 2g logs i look at have smooth values.

I've seen other 1g datalogs where all these parameters increase very smooth and linear through out a pull so I'm not sure its a 1g thing. On that note I was wondering if there might be a way to increase the sample rate of the datalogs?

very possible..... if the car accelerates smoothly its probably a reading issue of some sort

I've video recorded my boost gauge and tach to try and better adjust the maf comp sliders and boostEst and it is nice and smooth as I accelerate nothing weird going on with that part of it. It feels pretty smooth through the rpm band as I accelerate as well.

The more logs I look at the more I'm noticing it seems to be the RPM, Speed, Airflow, MAF and MAFRaw that are all very similar in the fact that none of them increase smoothly. They all jump around up and down through the entire pull.

 

[GSLENK]

One thing people do is make a smoothed rpm. Raw rpm is always jumpy in my logs. I forget how to add a smoothing factor, but one of calan's Link Tools videos (if he has not removed them along with link tools) shows you how to do this in link. Also I am sure you could ask tom or dave or anyone else on link forums how to make a smoothed graph.

The trade off is a slight phase shift to the right for better smoothness (as long as you are reasonable on the smoothing factor, use around 4, much more and it will go pretty far to the right). I am not so sure about speed. If you look at link tutorials for setting HP settings, they go over speed vs rpm, and even in those videos IIRC both are pretty choppy, and that's form the creators themselves.

Yours looks fine.

 

[Marchev]

My logs look exactly like yours, been like that ever since I've had link. At first I thought it was an issue too, but after some digging around it looks like that's just how it is.