Can someone direct me to some info on the ecu? I want to understand all of what it does. My car is an 88 GTU.

 

It controls the engine


Really though. It isn't special or "tuned" differently from base NA's.

Basically it manages the fuel injectors and stuff.
02 sensor
temp sensor
hmmm...
BAC
ACV

You really don't need to know a whole lot about it unless you think it's bad and need to trouble shoot.

 

Download the FSM, and read the pinout.

The ECU takes readings from various sources, and calculates injector duty cycle.. Then it does about 10 more things on top of that/

 

i strongly disagree. i think max tolerances are very important and knowing how far a stock ecu and its accessories can go is important.
for example, i was going to half bridge my n/a on its stock ecu. its an S5 and mazdaspeed7 politely talked me out of it. i was dead set on doing this, but was convinced otherwise. judge ito did a full bridge on an S4. why was he so happy with his full bridge when mazdaspeed7 convinced me not to even do a half? i believe it came down to the capibilities between the systems.
if someone can prove that wrong, wonderful. i would still love to do the half bridge. however, i was convinced by someone who had done something similar not to because it supposedly wouldnt run right and i would less than pleased with the results.

 

About a month ago I slid into a ditch being an *** on wet roads. I know that I severely dented my left rear rim, and ever since the car has had real bad cornering (chirping rear wheels, etc).

Despite the fact that I know I need new rims and probably new suspension, I also know that the ecu controls something having to do with the rear suspension, and I want to learn about it.

 

ecu... rear suspension.. unless youre referring to the electric suspension, there's no connection. there's more than one computer in the car and i'm not sure which one has to do with the electric (whatever its called) suspension.
you "know" that the ecu controls have something to do with the rear suspension?? this one is new to me.

 

uhh no it doesnt, its not like the computer controlled cars of today...the ecu only knows what its sensors (all forward of the firewall) tell it and there is NOTHING it could control in the rear. everything besides engine control is run by other computers or other stuff. if your thinking about the aas then dont b/c 88 gtu's didnt come with it and it wouldnt be working after 16 years anyways.

 

Not all sensors are forward of the firewall...Think about the atmospheric pressure sensor location...

The AAS cars had a seperate computer for the suspension that tied in with the power steering computer, but not the ECU

 

my GTU didn't have it either.

If you had the AAS it would be on all 4 corners.

If it's still plugged in then disconnect it. The shocks are toast lol.

What I meant about not needing to know what the ECU does.... I mean in situations like this.

When your talking about max injector duty cycle or fuel maps,knock function,boost fcd,etc then you'll need to know a bit about it but there isn't really anything we can do about it.

You can go EMS,Rtek, SAFC,HKS, and that's it pretty much. You never really have to get into the ecu.

 

right, but his question made my ears perk because i'm curious, too. of course, i'm curious because i want to know WHY my car can't handle a half-bridge (if it cant). i want to know WHY my ecu can't handle extreme changes in timing that a large streetport or half bridge would cause.
no, there isnt anything we can do IN the ecu (well, not me, some people can), but there are things we can avoid doing because we know the ecu won't like them.
i started a thread a long time ago about the capabilities because i was hoping to get answers. i didnt hear much of anything great. maybe not knowing what questions to ask is why.

 

I know Higgi or some one doing the Rtek has a boig thread on what they found inside.

 

As I said, I really know nothing about it. I thought I had heard once on the forum something about ecu on 88 GTU's controlling something having to do with the rear wheels.

Also, on a Top Gear episode comparing the Porsche and Mazda FC I was pretty sure the model was a GTU.... and they said something about small alterations in the rear suspension controlled by the computer.

Someone smart come in here and help me out.

 

how about this, go out to your car and find ANY wire or electric structure that even touches your suspension.
like mentioned, the only thing electronic was the AAS which apparently your car didn't have and was controlled by a seperate computer. the ecu is for the engine. and, as mentioned, there's other computers in the car aside from the ecu such as that that would control the AAS.

 

well seriously though, these ecus are not anything modern, mid 80's tech is not all that far from the computers that took up whole rooms(j/k). they have very limited capacities and no room to learn anything much beyond stock settings, its not that mazda didnt want to put a computer that could do much more, its that they couldnt, too expensive and/or the technology was not there. i will give them credit b/c you can upgrade pretty far with a stock ecu espically with a safc and other piggy back controls with bolt on mods but serious engine mods the thing cant handle. im willing to bet a newer cellphone has 1000times the speed/memory/capacity of these older ecus. the s5 ecu alone was 10times faster than the s4's...so think about that change over 4 years (1985-1988.5)and its been 13years since the last fc was made...just about.