Datamaster Help

Forgive me for bringing this up if it has been asked before. I had no luck searching.

I have Datamaster and am interested in learning what everything means (more or less). I was wondering if there is some kind of FAQ or tutorial around. If not, I'd be willing to make a log and see if someone can take a look to see whats going on and maybe make a suggestion or two. My car seems kind of sluggish lately (maybe its just me) and I'd like to learn about this stuff.

Also, what is the best way to log some information for analyzation? Is it best to start out cold and let it warm through normal driving or start hot and go through all gears or some WOT?

Thanks in advance for any help.

http://members.aol.com/InjuneerZZ/Index.htm

Thanks...I'll check that out.

What you need to record depends on what your problem is. If it starts OK cold and runs OK cold, and survives the transition to closed loop with no problems, you could avoid logging a cold start. That's going to produce 2 minutes of data with limited value, waiting for it to go in to closed loop. On the other hand, if it starts hard, runs poorly after cold start, or shows signs of problems with the transition to closed loop, that's what you want to record.

Generally.....

-do NOT reset the PCM before you log. You lose all the stored long term corrections.
-get maybe 30 seconds of stable idle. Do NOT rev the engine while its sitting still - useless data.
-record a couple of minutes of "normal" driving, part load, varying the RPM and throttle postion over a wide range, to operate in as many of the fuel trim cells as possible.
-then try a WOT pull, through at least 2 gears. No need to take it to 120mph..... just reach your normal max rpm and shift it so you can see what happens on the shift, then run it up to max rpm in that gear.

If you can set up what parameters it records, delete the things you aren't interested in, or things that are essentially duplicate records that slow down the logging process and increase the volume of data. You will get both IAT temp in degrees and IAT sensor voltage. You really only need the temperature. Same with coolant temp. Record in degrees F. Some data logs show long term and short term fuel corrections in absolut numbers (e.g. - 128) and in "percent" (e.g. +15%). You don't need both. I prefer to so the absolute number.

The first thing I do when I get a data log is put it in an Excel spreadsheet, then move the colums of data I don't need off to the side. You will have a column for BAR, target idle RPM, learned IAC position, some cylinder numbers, other data that I have no idea what its for..... alll those get moved out of the way, so you can look at only the columns you need to look at.

Then I drop to the bottom, and do a table for "max", "average" and "min" readings in each column. That will often highlight the problem areas in really large logs. Using the "search" function in Excel, I can go to the specific cell that produced the data extreme.

After a while, you will get the hang of it.

Along with the info Fred has given ya look at this also:

http://www.seth-sons.com/offsite/tuningstuff/dm32man.pdf

Datamaster's PDF file..:)

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