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First Day of Tuning Advice

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Old 03-21-2009, 11:01 AM
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Default First Day of Tuning Advice

Righto, I've spent the last couple of weeks reading, searching and preying to any sort of god, about Megasquirt. The week before last I went ahead and installed an M45 Jackson Racing setup, AEM wideband (would have gonna innovate but I bought this when I thought I was going for AEM F/IC), and a MSPNP unit for a 96/97 model.

At first it wouldn't idle... turned out the check valve in the vacuum line was the wrong way around. But after that I got it started it up and it was idling healthily. I then tried that little edit to make the AEM afr's show up in afr instead of voltage. I assume the values didn't get changed because it ran terrible! So I switched that back and also deleted the MAF. Got it idling again and was content with myself after a hectic week.

Took it for a drive and realised that it needed tuning in a few key areas. The most concerning area for me is regular cruising with light throttle at about 3k rpm, it gets dangerously lean. It goes off the chart on the wideband gauge and goes beyond 17 on the MS setup, to the point where the car jerks a bit. A similar jerky feeling to engaging the clutch without gas.

The other problem area is when I give it gas, it gets down to about 10 for the afr, bogs down like buggery and really goes slow.

Now, conquering this shouldn't be too much of a problem. I need to subtract some fuel under heavy load and add some for cruising. I also need to make sure that the accel rpm addition stuff is turned off (for some reason I think it may have been left on my base map).

The plan was to make some small changes, drive around datalog, stop and then use the VE analyzer and see what I need to do. Is that a good idea?

My main issue is the ms manuals are currently down,

http://www.msextra.com/manuals/MS_Ex...ing_Manual.htm

So I'm looking for a little extra guidance from you lot. How much should I try and change the fuel values with each attempt? How exactly do I rescale the table so that the max kpa is lower? I would just go at it and try the scale by box but not exactly sure how the number I put in pertains to the table. Any tips for tuning to a supercharger compared to a turbo? Any helpful insights?

Obviously, I'm not going to doing a tune of professional standards. I fully intend to make the trip to diyautotune and get it done properly in the not so distant future. But for now I need something that I can drive around without fear of damaging my motor.

Thanks for any help.

Jack

96 running stand alone mspnp96/97
aem wideband
jackson racing m45
Maf deleted
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Old 03-21-2009, 05:29 PM
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Have you tried using Megalog viewer?
Thats what I've been using, it will automatically adjust your fuel table based on your logs.
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Old 03-21-2009, 05:55 PM
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No I haven't. Me and my buddy tried some tuning on the fly that was going ok. We did start a log but it didn't seem to have saved properly. I guess we didn't hit the "off" button before disconnecting. Odd... when I check where they save in megatune, it shows a file but it won't appear anywhere else.
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Old 03-21-2009, 06:11 PM
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Sounds like you've got a pretty good idea what you're doing so far. You can scale the VE table by opening Megatune, going to Basic Settings, Fuel VE Table 1, then changing the kPa numbers on the Y axis. Of course you'll have to adjust the fuel cells to interpolate what they should be.

The first couple times you go out to datalog, I'd suggest you make sure it's warmed up, then just go drive around for 5 minutes or so, run the analyzer, save the map, then do it again. You'll make some huge steps improving the tune after a few scessions. Once the tune gets closer, no more stumbling or off the chart AFRs, then you can start making some longer logs to get the finer adjustments.
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Old 03-21-2009, 06:18 PM
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Originally Posted by jdmaddox88
No I haven't. Me and my buddy tried some tuning on the fly that was going ok. We did start a log but it didn't seem to have saved properly. I guess we didn't hit the "off" button before disconnecting. Odd... when I check where they save in megatune, it shows a file but it won't appear anywhere else.
It should let you pick where you're saving the file when you fist click to datalog (or alt+L). Mine saves no matter how I shut it down so that may not be the problem.
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Old 03-21-2009, 06:32 PM
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Well damn... Just read through the megalog manual, I had a completely wrong idea of what it did. That'll make things much easier!
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Old 03-21-2009, 06:35 PM
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I think the missing file is just a matter of first time errors.

Thanks a lot for that run down. Some simple steps like that should be a stickied post. Sometimes the problem, as it has been with me, is that you end up overlooking the simple steps and read some other hardcore stuff that has minimal effect.
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Old 03-21-2009, 06:39 PM
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A quick question, I had the rpm based acell enrichment disabled and the ego value set to 0. Should I change all this back to base map configs now that I'm going to let megalog have at it?

Also... my VE table really isn't suited for my driving. I assume to get one with better kpa positions I'm either going to have to change the current ones and re enter a bunch of values, or simply start a new one?

Or again, is this something megalog will take care of?

Thanks a ton.
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Old 03-22-2009, 03:20 PM
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Datalog is brilliant. The changes it makes are absolutely perfect, what a difference!
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Old 03-24-2009, 12:50 AM
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Going to look more into datalog and how it works, my main concern is what targets it uses for the fuel tables (it uses either the mlv default or the one from the msq file for anyone stumbles across this in a search). I think my ghetto rigged intake is way too restrictive and really causing some top end power issues. Running rich most everywhere too.

But on the whole, really pleased that a regular person like me is able to switch out the ecu and add a supercharger and make it work!

Last edited by jdmaddox88; 03-24-2009 at 09:34 AM.
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