ramses666

iTrader: (1)

I'm starting a New Thread to Explore What's Old & What's New with ECU's for my ancient '88 S4 NA.

I'm basically stock with an RB True Dual Exhaust & would like to be able to pursue "Various" Upgrades in the Future.

I'm interested in Forum Members' Experiences & Opinions about a Sustainable Upgrade Path & the Various Failings of Past Experiments.

Simplicity vs. Complexity

Ease of Install & Ease of Use.

Support & Compatability?

I'm not intending to build a Race Car for Competition or make outrageous HP numbers. I have a Street Car & would like to keep it that way.

Proper Functionality & Monitoring/Tuning Ability without paying for Dyno Time is worth something extra.

Using my existing harness is a stong benefit.

Eliminating the MAF is worth paying something extra to me for possible upgrades.

I'm also looking for the ECU pin-out function list on the Stock ECU for the '88NA so I might get a Better Understanding of WTF else my ECU is up to, other than being trapped in it's own Factory Settings. For some reason my Searches came up with NADA...

fc323

https://www.rx7club.com/engine-management-forum-37/
Here you go, since its hard finding stuff

lastphaseofthis

iTrader: (8)

i hate answers like the ones above... you have a valid question that i wish i could be answer, but if you ask t haltech forum they will sell you the best haltech for your goals. same with aem, or adaptronic.

i choose ms3-pro, price and function list are great. my 2nd choice would have been the adaptronic e1280s, and i may still end up with one of those also.

before the ms3 pro i was all rtek. and if your goals are 350 or lesss, stick with tried and true r tek.

another reason for me getting the ms3 pro is i am a tuner and 2 other guys have bought them locally and are going to get me to tune them, so i wanted to be familure as possible with it. once i downloaded the software and started playing around with the features i saw it was a fit for me and most of my goals.

i also downloaded the software for haltech and adaptronic, but didnt seem to find my way into the really good stuff easily. seems like one of them wouldnt load with out owning the ecu first.

ramses666

iTrader: (1)

Good Answer. I'm leaning to the MS3 Pro. I'm wondering about installing just the board in a Stock ECU case & keeping everything intact.

Is there some reason to Not go this route?

I can easily add one or two wide-bands & MAP sensors.

It seems simple enough... How's your experience been with it?

ACR_RX-7

iTrader: (1)

The MS3Pro comes in its own plastic sealed case. Not too easy to rip apart and would likely void any warranty it would have.

You can set up a MS3X in a stock case and use stock type connectors. DIYAutotune.com has stock harness plug receivers. It's a DIY job. You would have to solder a board and jumpers to get the factory harness to work.

The MS3Pro comes with an 8ft harness. It is highly recommended to simply replace the whole harness to avoid any possible lurking issues. That being said, you can also repin the harness to the MS3Pro plugs. I think they sell patch harness lengths.

Then again, I'm a liar it looks like. I just did a search on DIYauto tune and found this.

https://www.diyautotune.com/product/ms3-pro-module/

You can then install this in a factory case and set it up that way.


If you want connector pinouts, go to Foxed.ca and look at the wiring schemetics and plug connector id tables. It's all there.

lastphaseofthis

iTrader: (8)

i thought about guttin an ecu and using the 850 board, it will be the cheapest route. i bought these to make a plug n play adapter for one of the cars i will use it with.

https://www.diyautotune.com/product/...ndenso-52-pin/


im doing every route you can imagine..
two cars gets the full 250 harness
my nissan v8 engine gets the 60 dollar ampseal connector on the end of it's factory harness
the turbo FC gets a patch harness made from the 60 dollar ampseal connector and the denso 52pin bob above.

ramses666

iTrader: (1)

Ok... I found the ECU diagram... It would be nice to have all the pins connected & Stock things doing "Their Thing" until I tell them other-wise or alter the function in software & re-purpose the wiring in the stock harness.

Why? Who Knows? Perhaps I want to use the Speed output data for the deleted power steering pump pressure to operate a rear wing when low speed cornering or open duct-work or tap the e-brake for auto drift...

The possibilities for other applications of deleted stock items like the AFM & other check connectors or warning lights or the entire air-vacuum system is a Proper Part of an Upgrade Path for me... I would guess that most don't care about that in their Preferences.

How many Pins do not get used when using the MS3?

Can you get to all the functions of the Stock ECU with the software & alter them to Suit "Whatever"?

Shainiac

iTrader: (7)

I've built two Megasquirt systems for an FC, an MS2v3.0 and and MS3Xv3.0. I highly recommend the ECU if you have some electrical aptitude. If you buy a MS3Pro or a MS3X pre-assembled, it won’t be much more work than any other standalone, but the DIY boards are an undertaking. The confusion with Megasquirt is from it being so configurable. There is plenty of rotary-specific documentation, but the main manual (excellent) can be overwhelming because it lists basically EVERYTHING you could do with the ECU. The features and software for the MS3-based ECUs is hard to beat at any price.

I made a brand new harness for both of my ECUs. You COULD build a patch harness to plug into the stock wiring harness, but 50% of the benefit of going stand alone is ditching the cracked and brittle stock wiring harness. I have a good friend who builds lots of BMW patch harnesses for stock harness turbo-swapped cars. They have much higher quality wiring and are less baked from heat, so it works great for them. He actually just guts the stock ECU case and solders directly to the connector.
Building your own harness isn’t that challenging, you just have to be sure to check your work often and stay organized.

ramses666

iTrader: (1)

I've constructed more multi-pin cables & connectors than probably anyone here as an Audio Engineer... I'm very comfortable with complexity... Operating 64 inputs with side-chain monitoring & processing for multiple outputs is Mere Child's Play to me... to be Honest I prefer Proper Complexity.

So correct me if I'm wrong...

I can use all the Stock ECU pins in the Stock Harness?

Software allows me to use all the Stock ECU functions & change them?

My stock harness & engine function just fine right now (knock on wood), but I removed & blocked off the air control unit & cut the belt for the air pump when I put my RB exhaust on. I'd like to put it back on & get things working correctly again before removing more stuff & making a mess of things... I've done that once before & I'm looking to do things in a Smarter Fashion this time around.

lastphaseofthis

iTrader: (8)

im in the middle of it all, i want to keep the ability to throw the rtek back in the car.. but running the ms3 on the afm would be harder to setup then its worth. so think about what wires, they wil do and that ones that will say, there are a handful of pins for emissions you can opt out and re purpose
.

ACR_RX-7

iTrader: (1)

The speed output comes from the cruise control module, not the PCM. The PCM never sees a speed input in stock configuration. The speed sensitive power steering is not built into the factory PCM.

There are tons of threads on it, but the easiest place to get a speed signal is off the wire from the cluster to the cruise module on the driver side.

FC3S Pro v2.0:&nbsp Tips 'N Tricks - Cruise Control Speed Sensor Wire

https://www.rx7club.com/megasquirt-f...-ms3x-1093343/



As far as what doesn't get used with MS3PRO, that is entirely up to you. Normally the CAN bus wires, the extra 6-8 injector outputs, several PWM outputs, and a couple others are left over. Again, the ECU is 100% universal, so it has features that the rotary doesn't require.


As far as having the ECU perform 100% like stock, that's a big unnecessary undertaking. As long as you have the engine running efficiently, there is no reason to keep the AWS, EGR, and the Cold start functioning. The purge vavle for the EVAP system can be programmed in, which is a good idea.

clokker

iTrader: (2)

After swapping the FC driven gear onto a FD VSS unit, you can get a vehicle speed output direct from the transmission (the FD unit will bolt right on) and send it to the ECU and also drive an electronic speedo.
If you're into that sort of thing.

ramses666

iTrader: (1)

I agree that many of the stock emissions features & the silly AWS systems can & will deleted.

As far as the Speed Sensor thing, I was talking about the Power Steering Switch in the ECU that drops the pressure as a function of speed... there's a transition point in there... or so I thought...

I could jump right in & white-board a good plan... Hope!

The Cruise Control Thing is Completely Different - but Wow! Traction Control! This where the Coolness Factor comes into play... Thank You for the Links!

As far as the Harness & adaptors... I have found that ANY Connections can & will induce noise & that Monkeying Around with an Old Harness can be Problematic...

That's why I'd prefer to go with Mounting the Board directly into the Stock ECU Case & doing all the connections in the ECU Box - without trying to remove the Good Condition Harness & Connectors in the Engine Bay... Besides savings in Time & $'s...

I'm Lucky to have an S4 that's Not Broken & Not Molested Yet... I'm Not in a Hurry & I Believe Good Planning at the Start will Help Ease Future Frustrations.

Shainiac

iTrader: (7)

I would suggest making a small jumper harness using either an old ECU for the female connector or the DIYautotune connector linked above. You shouldn't have issues with having a second connection in the harnesses if everything is grounded and shielded properly.
As for rear VSS, it's very easy to get working. Front VSS requires some fab work OR an OEM ABS-equipped hub and ABS sensor. I also have front VSS working, but it gets noisy past about 60mph. Currently trying to solve that.

ramses666

iTrader: (1)

Thanks for the answers I needed... If Aaron Cake is Happily using one with success then I'd hang my hat on that...

Other Opinions or Options for an ECU Choice?

ACR_RX-7

iTrader: (1)

Nope. It bumps idle when it sees a pressure spike. That's all. You don't want to kill your car just by turning the wheel. OEMs have been using PS pressure switches for years to raise idle when steering wheel input is sensed. It only functions at idle too, so cruising will have no affect to the running strategy.

Think about it this way, if you have cruise control on, you don't want steering inputs to raise the rpm via the switch.

ramses666

iTrader: (1)

Perhaps you are correct, but I seem to remember drift guys complaining about the power steering assist transition point causing an annoying oscillation around 25 mph... or when the wheels would spin, the steering wheel would stiffen up ect... Then there was something about the steering computer thingy causing annoyance for something or other...

It's a vague memory from long ago... I'm planning on de-powering the Rack & junking the PS anyway, but I'm curious about what different functions the Factory Used that I might exploit for Other Novel Uses.

ACR_RX-7

iTrader: (1)

I would not get too hung up on what the factory PCM strategies are/were. There is no reason to exploit anything secret because there are no big secrets. A standalone PCM has all of that programmed in and you can set up whatever features you want.

The speed sensing PS was only on the S5 cars, I believe. It used input from the speedometer in the cluster to the cruise unit, and finally to the PS computer. The steering stiffening up when the wheels are spinning is normal. You want less assist at higher speeds, but drifting is a different animal.

ramses666

iTrader: (1)

Well... the Factory worked hard at silly things like cornering instead of just going straight... Why else bother with the DTSS thing at all? Can I make an active cam for that instead of a rubber bushing?

Awww... Just throw that Stuff Away... Mazda wasted all that effort just to make the car cost more, weigh more & be more complicated just to thwart my desires for perfection?

I thought that at least understanding what the factory did on the nitty-gritty, nit-picky things & why would be a good idea & I'm Curious what weird or mundane things already exist.

What Strangeness Exists? Rumor & Legend Drive Curious Vehicles!

ACR_RX-7

iTrader: (1)

They bothered because they were trying to follow the pack. Many other makers had some version of rear steering. The DTSS make the car unstable at speed and with wear, cause even larger problems. The FD has a track car style multi-link suspension with no active or passive rear toe. The Miata and RX8 also kept with the multilink rear suspension without any passive steering. The engineers tried something. It didn't work. They scrapped it. It was not about weight, cost, or complexity. It was about trying new things and setting a standard.


The rear suspension on the FC is not even that good from the beginning. They went from a live axle to the trailing arm system the FC uses. It has geometry issues when lowered and has a poor roll center stock. The arms also have a strange camber gain along with binding issues. That's why they changed after the FC.


The understanding is already there if you search long enough. The general consensus has been that the FC is a decent car, but definitely has its shortcomings. Ideally, you want a dual a-arm setup up front, with a better designed rear multilink.

Not saying the car can't handle well, because it has been demonstrated numerous times that it can, but the FC is an evolutionary step in Mazda's sports car development. From the FB to the FD, the Miata and even to the RX8. There are numerous refinements that make the car a argueably better car.

One of the many things that I dislike about the FC is the overreliance on the body CPU. They fail and cause all kinds of havoc. Back in the 80s, manufactures had not mastered a true BCM, like cars of today.

ramses666

iTrader: (1)

Thanks... That's real helpful... Other Perspectives are Valuable to me...

I wonder about strange things like having an electric OMP with it's own supply of lubricant instead either pre-mixing or stock using crank-case oil... I seem to remember the problem being one of the consumer would not be willing to do it reliably & too much of a pain...

The original idea was for the OMP Supply to be separate from the crankcase... Having electronic control & monitoring of the OMP System with some "Special Secret Sauce" in the Tank might be an improvement for reliability, performance & fault tolerance over either current system.

The AWS could also serve a similar & different function through a different part of the intake.

Like-wise, the Exhaust Port Air might be useful to help with Tuning by testing the Exhaust Temp & Wideband vs. Port Air Pressure for Timing & Fuel Tweaking without Detonation. If I go over Lean with a Port Air Pressure of X, then Stop the Timing/Fuel Advance...

Bells & Whistles can be Re-Tuned to play a different Song... I'm just trying to Decode & Settle an Old Score before embarking on Writing a New One.

ACR_RX-7

iTrader: (1)

This has been covered ad-nauseum in the single turbo threads. The short answer is, premix. The long answer is in this thread. Many engine builders agree on the same thing. Premix your engine to keep it lasting.

The oil injector is a small teeny hole that hits the middle of the apex and hopefully spreads out. It also leaves deposits from the crankcase oil. There are kits to draw from a separate tank, but you still only get oil right on the center of the seal.

With premix, the oil is mixed with the fuel charge and hits the whole apex seal and the side seals. Better engine life abounds.

https://www.rx7club.com/3rd-generati...-motor-887275/


Are you talking EGR port pressure? I do not think there is any tuning correlation to pressure there and mixture control. Now, using a UEGO and a EGT setup can be used for tuning, but it's not that cut and dried. The rear iron is typically hotter than the front and tuning timing based on EGT and lambda is not the most accurate way. The best way is with a knock sensing system and a dyno. I'm pulling a quote from another person. Name omitted to protect the innocent:


The big thing to remember is that a 13B doesn't make too much more power close to the knock threshold, vs a couple degrees back. If your power split between max timing and say 5 degrees back is less than 15-20 hp. Stay on the safe side and keep timing back.

You also should consider water or meth injection, if you go turbo.

ramses666

iTrader: (1)

Off Throttle Lube with Pre-Mix is a Loser... The separate tank system with electronic control is the way to go & maybe a very light premix... Adding OMP Injectors like RX-8 with 3 & a Custom Lube seems Far Superior to just dumping pre-mix in...

I was thinking more like using the EGR circuit for an in-car Popcorn Popper... Over The Top Switch for Exhaust Cut-Outs... AWS for wind-shield washer fluid injected manifold cooling-mist. The Shift Light Function for Exhaust Tip Flames & other such Non-Sensical Flights of Rotary Fantasy.

The Link simply confirmed what I'd already thought... Thanks!

j9fd3s

iTrader: (3)

the speed input goes to the power steering computer, not the engine computer.

DC5Daniel

iTrader: (10)

It's pretty common to squirt a little fuel (coincidentally premix as well) on decel to combat the no lube on decel argument. No one is counting MPG's on a rotary.