Jeff tries to make a hot rod out of a farm truck. '92 Mighty Max

[Jeff V.]

I'd have to add it up. I know it's a lot

Since it was half off day, I grabbed the flash ECU from that 98 Montero too

I've got code from 4 or 5 different 6G74 SUVs now, plus all the car stuff I've collected. If I can't get my engine swap running right after all that, then I really need to stop doing this

The main reason I dumped the code out of this is I want to see if I can write a version to upgrade the MAF.

In 1990, the trucks had the 'trash can' style MAF that the 1G DSMs used. In 1991, they switched to the plastic MAFs we're more familiar with from the 3S. This required code changes since the MAFs read differently. It's the same problem we run into with putting Evo MAFs into a 3S.

It's probably completely unnecessary, but it could be useful since parts for these trucks are somewhat scarce.

There were some technical curiosities I wanted to finally satisfy as far as how the really early V6 stuff relates to the DSM code. I'm not going to waste too much time on it, but I'll scratch the itch a little.

[DCIV]

I could just see you saving the file in a folder that has 100's of models of vehicles, enough that you forget if you already have that one done. Haha.

Coop

[Jeff V.]

I actually have a copy of a dealership update CD ROM that has hundreds of flash files on it. They're in a weird format, but I could extract them if I needed to.

That's in addition to the dozen or so actual ECUs I have.

[DCIV]

I know this was an issue with the gm mas but could you make the older style engine stuff work well with the newer mas? I seem to remember something about wave length or output style? But it's all okay if it's mitsu?


Coop

[Jeff V.]

That's exactly what I'm talking about doing. The Mitsu sensors output a frequency signal. The number of pulses per millisecond represents how much air is moving through the sensor. As the sensors get newer, the scale changes, but the principles stay the same until about 2004-ish. Some other sensors are voltage based. 0-5v. I think some of the GM sensors are also frequency based, but they're on a very different scale that makes it difficult to adapt our ECUs to.

[DCIV]

When do they move to blow through? Is the mas that big of restriction? Does it make that much difference on how it runs or tuned? I guess what's the big obsession with the mas?


Coop

[Jeff V.]

Other people may have different opinions. From what I've seen, the two issues are restriction and accuracy. After a certain airflow point, the sensor either becomes a restriction on air entering the system, or it just stops accurately counting the air that comes in. The newer sensors are more accurate across a wider range of airflows, which means better idle, better closed loop performance, and more accurate A/F ratios at WOT.

The DSM guys were concerned about the old MAFs because they weren't very accurate, and I think they were more prone to damage from vibration. Again, not a huge issues for the trucks, but it does open up some options to replace/upgrade your MAF and also load accurate calibration values into a newer ECU.

[aaronatstate]

[quote=""Jeff V.""]It's the same problem we run into with putting Evo MAFs into a 3S. [/quote]

What issues are there? I have one, but it's been a while since I put it in. I don't remember any issues though, except changing the values in the tables?

[Jeff V.]

I don't remember any issues though, except changing the values in the tables?

That's all I meant. You have to change the tables to go from a 1G MAF to a 2G, same as when you go from 2G to 3G on a 3S. It's just a little more work with the trucks because they're older and not all of them have EPROMs. It looks like SOHC Stealth ECUs with a code swap would be a valid replacement if you don't want to go to the trouble of doing an adapter harness for a flash swap.

[aaronatstate]

[quote=""Jeff V.""]That's all I meant. [/quote]

Whew, thought I was losing my mind!

[ChargerX3]

Part of me is tempted to stash an evo maf inside the trashcan to keep my stock look.

[Jeff V.]

Well, I've got a spare trash can if you want one to hack up. I'm selling the actual sensor to a guy on the truck forum.

[ChargerX3]

Ill save you the trouble of shipping. I wont need mine for anything anyways. I finally found a red bracket in a max to mount the 3s style airbox, so I may never go back. Was just a thought.

[stealthee]

[quote=""Jeff V.""]That's all I meant. You have to change the tables to go from a 1G MAF to a 2G, same as when you go from 2G to 3G on a 3S. It's just a little more work with the trucks because they're older and not all of them have EPROMs. It looks like SOHC Stealth ECUs with a code swap would be a valid replacement if you don't want to go to the trouble of doing an adapter harness for a flash swap.[/quote]

I had a 93 TSI that had a 2g MAS swapped on it. It was on it when I bought the car and I was told it is a direct swap. The wiring colors are even identical.

[Jeff V.]

Electrically it's fine. You can go all the way up to the late 3rd gen sensors with the same wiring.

From a calibration standpoint, it's very different. I doubt it's that big of an issue on a stock car. Especially a 150hp truck. But on something boosted, it's significant. And I just like doing things the right way

[stealthee]

Well, I was a little clueless when I had that car, and I ended up frying the compression rings due to some of my lack of knowledge anyway, but this is good to know. I know my cousin was talking about putting a 2g MAS in his 93 TSI so I'll make sure to help him do more investigation into the process.

[Jeff V.]

It's easy if he's got an EPROM ECU, flash ECU, or something like an SAFC.

I've actually got a DSM EPROM ECU in my box. Let me know if he wants it. I'll give him a good deal.

[stealthee]

I'll let him know. I'm not sure which direction he is headed with the car just yet. Also, he's one of those people that money burns a hole in his pocket and he tends to spend on things for RC cars before buying car parts he needs. Lol

[Duck Vader]

[Jeff V.]

Guess how many times my truck has left me stranded.