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Custom Tuning a Pathfinder ECU, the Project begins.


Nefarious
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Well I just finished getting the 240SX all up and running on a custom tuned ECU, got it all ready for the turbo setup. Now it's time to do the Pathfinder!

I've got a 1993 Pathfinder with a VG33E swap. VG30E cams, high flow custom intake, OBX headers, 2.5" custom exhaust (hi-flo magnaflow cat/flowmaster muffler). All this is running on a stock Pathfinder 3.0 fuel system and tune and frankly it's not keeping up. There is some serious untapped power and economy with my setup so it's time to tune the pathfinder! I will also be getting rid of the seriously tiny stock maf and using a massive N60 Maxima maf and modifying a modern vg33e intake manifold/65mm throttle body.

 

So here's the Pathfinders ECU once you remove the lid and desolder the stock EPROM IC.

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Here's a shot from the rear. Be careful when it's apart! Static damage and physical damage alike will can the board!

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Close-up of the desoldered traces. Still needs a little clean up before the new socket goes in.

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Here's the stock EPROM.

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28 pin DIP socket installed in the board and good to go!

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Stock EPROM back in for now, ready for custom tunes! Just waiting on a few more parts in the mail before the process begins.Will update asap!

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  • 2 weeks later...

Not to dog on the diy spirit, but i remember seeing a place that does "ecu tuning". It was a "ship your ecu in and we will tune it for this price or we send you a tuned ecu for this price", thingy. You know, for the smaller brained people.

 

And...related question.

Wide bands; I searched it on the forum and nothing fed my appetite. I want to install a wide band but since i know less than what i what to know, i am unsure i want go through the trouble now or down the road.

Does the 'puter see the wide band as a normal o2 senor?

If not, do/could i run a a narrow and a wide o2? One for the ecu and one for tinkering?

Will the wide band fit in my bung?

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P.s., if anyone wants a guide on wideband install I would be happy to make a write-up. I'll be installing one soon on the rig. (probably another mtx-l, as they are fantastic)

Edited by Nefarious
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Yeah there are companies that over charge for less than ideal tunes, which are stuck with one set of maps. My goal here is to experiment and see what I can get out of it with my ideal setup.

DIY is just my nature I guess.

And to answer your question about widebands; it totally depends on your choice of wideband. If you want to run tandem o2s (wide and narrow) then any wideband will be fine. If you want to run only one sensor (wide) then the only one that I know of that will work is the mtx-l. It has a simulated narrowband output that you can then wire into your factory ecu and eliminate the narrowband.

And to update, I got the eeprom programmer in the mail!! Just waiting on the eeproms so I can get started. First order will be to convert to n60 maf and optimize fuel and timing maps. Things are happening!!!

 

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Edited by Nefarious
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The stock pathfinder maf is fine for a stock truck, but it is no where near adequate for maximum performance on an engine with opened up flowpaths and larger pipes. There is definitely power to be had in just getting the maf itself swapped over. There is a reason they use a nearly 90mm maf on the vg33e pathfinders as well. The stock VG30 maf is TINY and definitely not even close to adequate for a modified VG30 or VG33. I'll also be working on modifying the VG33E intake manifold to fit in a WD21 chassis, it has much better flow as well as a larger throttle body. Should all stack together for quite the nice power/efficiency increase when coupled with a good set of fuel and timing maps as well. :)

Edited by Nefarious
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Diy is the usually path i take, but something of this scope is a little out of my league.

Now i take it this will be more intensive then like a obd2 system to reflash, could there even be a handheld to reflash , or am i jumping the gun?

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Your tuning would be, Burn new ROM, remove old ROM, put new ROM in, figure out your next changes, Burn a new EPROM, install it, check it, figure out your changes etc etc etc.

 

So no, not quite as easy as ODBII tuning lol!

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Yeah its time consuming, it's just the nature of the beast.

 

I plan to get started by reprogramming the chips. Once I get going, I will probably start using an 8bit emulator to do live tuning and datalogging. Once I have a solid tune for each setup (vg30, vg33e, etc) and the performance is maxed with no knock detected then I can just hard burn a chip that contains the tune file from the emulator and the ecu can then be socketted with that eeprom.

 

It is a long and tedious process but the benefits are worth it to me! There is a lot of room in the vg30 tune for more power and more economy. It is conservative in timing and quite rich as soon as any real throttle is applied. Adding larger pipes, maf, intake and cams only sweetens the deal.

 

I'll get my truck on a dyno once this is all done and see what happens!

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  • 2 weeks later...

so i am dooing a vg33 swap since my enging just blew the t belt. will i need a ecu tune or will it run with my stock vg30 tune

also can i use a A/T ecu on a M/T because i am getting a jdm vg33 with harness and ecu?

 

Or is this tuned chip somthing you will be selling in the future?

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Your truck will run well with just the vg33e swap and a stock vg30e efi system. You will definitely have more power than stock with the swap but I'm just trying to extract as much tune and bolt on performance I can get out of the vg n/a setup (for now). There is a lot of power to be had after the vg33 swap to extract the most performance and efficiency from the tune. I know from personal experience that my factory 3.0 tune and efi system are not up to the task of getting maximum performance out of my modified 3.3 setup.

 

Once the wideband and eeproms are in I will log and show my progress.:)

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I'm so happy someone's finally doing this. As a computer engineering student and eager-to-learn car fanatic this is seriously the perfect combination of my interests. Best of luck and keep us updated!

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I'm also in electronics engineering tech school. Going to specialize in automation next year and get into robotics or renewable energy depending where the jobs are.:)

 

What are you specializing in?? Nice to see some fellow tech nerds on the board.:)

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  • 2 weeks later...

Ah, that makes sense haha Not entirely sure what I'm going to be specializing in still :wacko: I'd love to get in at a company like Koenigsegg, it just looks like so much fun (although there's only a handful of those jobs in the world -___- )

 

But just look at how awesome this guy's job is!!

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  • 2 months later...

Just an update, work has finally been slowing down enough for me to have time to work on other projects. I will be working on the custom ecu tuning again after next week. I have nearly all the hardware to get started and I'm just waiting on my 8-bit eprom emulator to show up and I will begin the process.

 

Will keep posted as updates arrive. I'm getting excited to see what this truck will do!

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