Question for those using MegaLogViewer

[Grover]

I'm having an issue where my motor doesn't always return to idle in a consistent fashion. For example, sometimes if I pull up to a stop light the rpm's will drop down to about 1350, whereas other times it will drop down to about 1100 (where I want idle to be.) Usually, if the idle doesn't drop all the way down but I give the throttle a quick blip, it will usually then drop down to 1100-ish. However, when looking in Tuner Studio or in MegaLog Viewer it will always show the TPS position as zero while at idle. What I'm trying to figure out if this is a tuning issue, or rather, if the throttle plate is just not quite shutting but the output signal from the TPS is low enough that the software is rounding the number down to zero.

So, based on the above, I'm trying to figure out if there is a way to get better granularity into what the TPS reading is (for example, could I get the number down to two decimal points.) Anybody know if this is doable?

[Colin]

I'm having an issue where my motor doesn't always return to idle in a consistent fashion. For example, sometimes if I pull up to a stop light the rpm's will drop down to about 1350, whereas other times it will drop down to about 1100 (where I want idle to be.) Usually, if the idle doesn't drop all the way down but I give the throttle a quick blip, it will usually then drop down to 1100-ish. However, when looking in Tuner Studio or in MegaLog Viewer it will always show the TPS position as zero while at idle. What I'm trying to figure out if this is a tuning issue, or rather, if the throttle plate is just not quite shutting but the output signal from the TPS is low enough that the software is rounding the number down to zero.

So, based on the above, I'm trying to figure out if there is a way to get better granularity into what the TPS reading is (for example, could I get the number down to two decimal points.) Anybody know if this is doable?

Usually a TPS has quite a bit of resolution.

How much "averaging factor" are you using for the tps?

My guess is it is the throttle plates. I know that with ITBs there can be issues with mis-alignment that will cause some of the plates to stick.

You aren't running closed-loop idle with the IAC, right?

Also, how are your map readings at idle, are they consistent?

[Grover]

Thanks for the ideas Colin. In regards to your questions:

My TPS averaging lag factor is set to 75

I'm not using closed loop IAC as I'm not running one through MS at all.

My MAP is remarkably stable at idle, hovering around 50kpa +/- 2 points.

I too have been thinking that it's likely the throttle plates not returning all the way, but thought an easy way I could measure this would be if I could get a true read on the TPS output. I know from experience that I can manually raise the rpm's quite a bit before the TPS signal finally moves from 0 to 1 percent.

A couple of years ago I used to be able to read the datalog info in Excel, but I can't see an option to change the format in MegaLogviewer. If I could do this I thought I could just re-format the cells in the TPS column to display down to a couple of decimal points.

[Colin]

It sounds like there is an issue with your TPS.

Maybe you need to re-calibrate it because it should be quite sensitive.

I run my TPS averaging at 95%. As long as you don't have a lot of noise in the signal than getting it as close to 100% as possible REALLY helps.

[02again]

Sounds like a Possible Air Leak. Saw that kind of a problem on a 325is, turned out to be a cracked vacuum line. Maybe?

[ar_kid]

You should still be able to open datalogs in Excel.

Open>Files of type>All files

There are options for importing various data sets

Do you have any adjustment on your TPS? Maybe the initial throttle opening is set at the 'dead' part of the pot.

Next time it idles high see if you can pull the throttle plate closed by hand