General Tuning the MAF Translator

[3kgtaddict]

I recently discovered that my 2g (with a 1g motor and eBay evoIII turbo) came with 650cc injectors, so now I’m trying to get it running right using the MAF-T/3.5” GM MAF that came with it. I’ve been googling for like a week and EVERYONE I’ve seen online says “set it to all 0s and have your tuner do the rest” but with only 3 knobs(idle,mid,WOT) it can’t be that hard right?!? Can anyone just describe the basics??

So far I’ve tried AUX 5 BASE 7 (for 650cc injectors) and with the other 3 zeroed out my AFR is around 11.5. With the idle knob all the way lean “A”, it’s at 15.1, one notch up at “B” it’s 14.1. It doesn’t run very well and also seems like fuel cuts out if I press the gas pedal at all while idling.

I read someone online saying it worked better for their 650s when they set it for 550cc injectors and it worked a little better for me as well. So I did AUX 4 BASE C (for 550cc) and with them all zeroed out AFR was 10.4. Then I got it just about perfect at 14.7 when I turned the idle knob all the way lean to “A”. Also, no fuel cut when accelerating from idle.

Then I read someone say that you have to fine tune the BASE or AUX knobs first before messing with the idle knob, then mid, then WOT.

Am I doing it wrong By adjusting the AFR with the Idle knob first? Aren’t the BASE - AUX knobs set according to injector size and don’t need any extra tuning?

Also, Is it correct that I set the second SWITCH to “ON” because it’s a 2g with a 2g ecu? Even though I have a 1G motor with a 1G CAS ? I read somewhere that the settings might be different with the 1G CAS but I have no idea

Could my problem be that I have to turn the boost up to match the extra fuel coming from the 650s? Or should I be able to balance out my AFR right now before messing with the boost?

If anyone could just point me down the right path I’m sure I’ll be able to figure out the rest!!! I’m not even sure if I’ve got the ECU into closed loop yet while adjusting the MAF-T and I’m scared to take it on a drive until I know I’m not messing something up

 

[DSMPT]

Are you sure that you are using the correct base setting way that matches with the MAF-T box version you have? IIRC, V1 and V2 have a different way to set the base.

 

[3kgtaddict]

Are you sure that you are using the correct base setting way that matches with the MAF-T box version you have? IIRC, V1 and V2 have a different way to set the base.

I’m not sure How can I tell which version I have? It says “Cfg. 2.02” on the front cover and “1.7” at the bottom right of the board on the inside. Here are some pictures

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[DSMPT]

I’m not sure How can I tell which version I have? It says “Cfg. 2.02” on the front cover and “1.7” at the bottom right of the board on the inside. Here are some pictures

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Seems to be V2, but I see you are not selecting 3.5" MAF. If it's V2, I think the mode switch #2 should be off for 3.5" MAF but the mode switch #1/2 both are in ON position in the pic. Do you have the manual?

 

[3kgtaddict]

Seems to be V2, but I see you are not selecting 3.5" MAF. If it's V2, I think the mode switch #2 should be off for 3.5" MAF but the mode switch #1/2 both are in ON position in the pic. Do you have the manual?

I don’t have the manual this was just in the car when I bought it and the guy didn’t know much about it. I had the first switch down but read online that it’s supposed to be up For 3.5” (I’m not sure which model though) but it definitely runs better now that it’s switched up. Not sure on the second switch though, I have it up because the car/ecu is a 2g but maybe it should be down because the motor/cam sensor are from a 1G??

Do I need to turn up the boost? Or should I be able to tune it to run properly with these 650cc injectors first before doing that?

Also, how do i fine tune the AUX or BASE knobs before I start messing with the idle/mid/WOT knobs?? I’ve read that I should just set them to 650cc (some have better luck setting them to 550cc) THEN adjust the idle/mid/wot. But I’ve also read that they need to be adjusted BEFORE messing with the idle/mid/wot .

 

[steve]

2G DSM/3S 2.02 manual

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[We're on Boost]

Not sure on the second switch though, I have it up because the car/ecu is a 2g but maybe it should be down because the motor/cam sensor are from a 1G??

In the Rev 1.3 the 2nd switch would be up (On) to set it for 2g, but yours is a Rev 2.
In your Rev 2 the 2nd switch should be down (Off) for 3.5" MAF.
I think the 1g or 2g selection would be because of the very different MAF Hz used by 1g and 2g ecus.
In the manual for your Ver 2, it's not even clear to me that it can be set to work in a 1g.

There gets to be some confusion identifying the different models of these things because they used the terms Rev, Cfg, Ver, and then at some point there was Gen 2, and then there was yet a different number printed on the circuit board as you showed in your pic.

Anyway, 2nd switch down (off) for the 3.5" MAF.
BTW are you sure your MAF is a 3.5"? The 3" measures 3.25" across the OD on the inlet side of it. I don't know what the 3.5" measures.

Here's the pdf manual for the Rev 2. I think this is all the same as the pictures that Steve posted:

Here are some pictures

Have to say, that looks like it's in really good shape inside. Not all corroded like the ones we usually see in here. Was it located in the cabin or in the engine bay?

 

[steve]

Here's the pdf manual for the Rev 2. I think this is all the same as the pictures that Steve posted:

Your's is for software 2.X8, mine was for Software 2.02. There are differences but it's like Where's Waldo to find them.

 

[3kgtaddict]

Thank you guys so much that’s exactly what I needed!

I wanted to mess with it and make sure I got it right before replying so I’m sorry it took so long I just haven’t had much time to work on it . You were right though! I measured wrong (OD instead of ID) and turns out I have a 3” MAF , so I flipped up the #2 switch ONLY, rest are all down and I set AUX to 4 and BASE to C (which is for 550cc injectors , even tho mine are 650cc, it worked better like that) and that got it to idle nice, it revs past 4k, and it doesn’t cut all the way rich as soon as I start cruising anymore!

I might make a new post once I’ve started driving it , if I can’t get it tuned right hopefully you guys will be able to help me . I should be able to do it with those instructions you gave me though. I just got it registered so I can start breaking in the motor and try it out tomorrow finally.

Probably won’t get an answer on this old thread, but I turned the idle knob a couple clicks to get it to idle @ 14.7 A/F ratio, but I don’t think it’s gotten into closed loop yet. Should I put it back to all 0’s and drive it for a bit before I start messing with the knobs, to make sure it goes into closed loop?

 

[We're on Boost]

I kind of have to start from basics on this thing, so I'm starting by looking at Appendix A and I think that is where they show how to differentiate between 1g and 2g DSM. You use the AUX knob to do that.

For 2g DSM and 550cc injectors, the AUX knob should be set to 4 and the BASE knob should be set to C.
For 2g DSM and 650cc injectors, the AUX knob should be set to 5 and the BASE knob should be set to 7.

But the four Mode switches, 1 and 2 should both be down (off) for a 3" MAF. 3 and 4 should also be down. So all 4 Mode switches should be down (off) at first, for the basic setup. You might use mode switch 3 and 4 later.
Anyway I don't know why you have Mode switch 2 up. It should be down for a 3" MAF according to the table on page 4. The pages aren't numbered but it is the 4th page in the pdf.

but I turned the idle knob a couple clicks to get it to idle @ 14.7 A/F ratio, but I don’t think it’s gotten into closed loop yet. Should I put it back to all 0’s and drive it for a bit before I start messing with the knobs, to make sure it goes into closed loop?

Once you have the AUX, BASE, and Mode switches set, then you can twiddle with the Idle knob all you want. But do you have anything that tells you when it is in closed loop? Do you have anything that tells you what your fuel trims are? Do you have anything that tells you if you are getting knock?

The other thing I wonder is, I noticed on your specs page that there was a 3000GT MAF on it before. My understanding is that the 3000GT VR4 MAF is the same as a 2g MAF. If that MAF is working ok, it supposedly is good for up to about 50 lbs per minute airflow which is pretty good, plenty good for any 16g turbo. Although the 3" GM MAF can go higher (not sure how much higher). You are breaking in a new engine? If the 3000GT MAF is working well, it would be safer to break in your new engine with it. Fortunately you have a wideband. That is really important. That's the main thing you need for checking it in open loop which is basically any time you are in boost.

Here is a link to the ECMTuning wiki page that gives you basic flow ratings and other info on the Mitsubishi MAFs and the GM MAFs.