ECU circuit board schematic

[terrets]

Does anyone have one of these?

[Mean Green]

Even most ECU rebuilder's do not have one. What you do not know is that our ECU is a multi-layer board. Meaning that there are not only circuits on top and bottom but there is also a circuit plate in the middle of the 2 that you cannot see. It is sandwiched between the 2 and repairing an ecu yourself that is significantly damaged is ill advised unless you are experienced with ECU's.

[terrets]

Im not as dumb as you think lol. I know that its multi layer. Obviously it would have to be to fit all the necessary operations of the ecu. Im trying to find out what exactly blew and what could have caused it. Not trying to rebuild it.

[Mean Green]

Well...considering your electronics skills, why don't you just back trace it until you get to the harness connection point and go from there. Just from the picture of the ecu, it appears that something grounded out and the crossing point just happened to be in the ecu.

[terrets]

I already tried lol. I cant back trace it. The board is too fucked up :/.

[terrets]

You think so??? I will do that now :). I think Im going to call Mitsubishi and try and track one down. I know a few other people were looking for one.

[terrets]

I think you might be right steve68 not sure though.....I ripped the capacitor off and it seems there was a very minuet bit a fluid under it. I think the frying dried it all up though...So I broke the capacitor open and there was no fluid that spilled out. It is damp inside it though.

edit: :lol: the acid is burning my arm a little bit. More itchy than anything.

[Mean Green]

I already tried lol. I cant back trace it. The board is too fucked up :/.

damn dude..that sucks...

What model is your ecu?

[terrets]

md159966

[terrets]

A mate of mine calls it "planned obsolesence"
Steve

^Haha thats funny and partially true. So you think its the capacitor that caused it? Im hoping so.

[terrets]

And do you think that the fluid dried up when fried? Cause it really didnt look like there was much if any there...I could feel it though haha.

Do you know where R115 and R116 connect to? Looks like the problem area

[terrets]

Ok. Thanks Steve.

[Austin@STM]

Sorry to hear about the ECU, sounds like its time to upgrade to AEM ;)

[terrets]

Thanks...haha Im tempted. I want to learn to tune and do it all myself though :). I figure EMU is a better platform.

[Austin@STM]

if your going to learn you might as well learn on the better system.

[terrets]

Lol but I probably wont ever get my car reliable :D. (from what Ive read.)

[Austin@STM]

Lol but I probably wont ever get my car reliable :D. (from what Ive read.)

A modified car will never be reliable, Having the AEM played a big part in getting my car where it is. Piggybacks can make power, they just dont work as well. Also the driveability of the AEM shits all over the stock computer. When i put in the AEM it was like going from a Taurus to a Cadillac. Everything is just smoother, and works better, but i have a great tuner in my corner.

[terrets]

I understand this steve.

Ya Austin, Im not sure theres any great tuners around here :/. Plus do you think I could get it all up and running all by myself (not sure about this lol)? Does AEM Series 2 have an A/F feature where it sustains the specified A/F ratio?

[colt45 gto]

A modified car will never be reliable.

Fucking Amen brother!

and what i have heard AEM equipped cars when setup right are better.

[terrets]

Lol I mean starting reliability. Not getting stuck places because of my tune :). Maybe I will go AEM. I really really wanted to drive my car one last month though :(. Do you guys think I could tune with an N/A ECU :lol:

[KeithMac]

If you wire the EMU with injector level control and timing control you could use the na ECU, you`ll be battling high timing and god knows what will happen with the fuel cut feature or where it`s threshold is..

The ISC motors are known to short out and blow the ECU so it`s worth checking that before you plug another in as well. Aparrently later style ones (Evo?) have higher coil resistance and are less likely to pop the ECU if they fail.

[KeithMac]

Problem is when you`ve been at 20+ psi you can`t go back..

[steve]

I had a failed one on a car recently where one of the coils was down to 2 ohms rather than the normal 28 ish. That didn't damage the ECU.

While the driver may not have burned up and let the magic smoke out, I think you'll find if you test them under load that the one that was trying to sink the current from the 2 ohm coil is either dead now or unable to pull the voltage down to 0v like it should. Anything below 10 ohms will exceed the current spec for the driver.

[KeithMac]

Best case would be just over 6 amps load on the driver rather than 0.5 that is should be sinking!.

[steve]

And they are only rated for Ic max 2A 10ms pulses at 10%DC

[terrets]

Im going to break into Mitsubishi's vault and steal all their schematics :D.

[CoreyB]

And they are only rated for Ic max 2A 10ms pulses at 10%DC

Thats good info Steve, would you happen to be SteveP on other sites ?

[steve]

On 3Si and DSMTalk yes, I'm Steve on all the sites that I joined early enough to get like here and on DSMTuners.

[CoreyB]

Yup I know who you are on those sites. I have used info you posted to work on ECUs. I trust you have some experience with them. Its hard to find info other than "replace the caps" " you need a new ECU".

[steve]

2A constant but it's only driven by short pulses so it's OK, maybe that's why it's working still?

It's always fun when the datasheet isn't consistent.
The first page and and tables on the second conflict slightly. So maybe it's 2A continuous or maybe not. You'll note the asterisk for the parameters that apply are the same on the front page and for the absolute max ratings and that the range of allowable currents includes 2A but says 0.7A is typical. Give the device power dissipation limits I'm more likely to believe the Ic(max)=2.0A PW=10ms, <=10%DC from the first page.

If you look at the four ISC wire in normal operation and you'll see that two of the drivers are always active. While stepping which two changes rapidly but when holding it's position two of the four lines are constantly active. If you trace backward to see how the MPU uses the two M5269L driver chips you see why two of the four drivers are always on.

Since your ISC coil was down to 2 ohms that driver was trying to pull 6A+ while it was active. I'm pretty confident that it's dead even if the chip is not burned up.

[steve]

They're only active when it's driving, the rest of the time it's off.

Steve

That's not what I see and given the circuit that controls them I don't see how it could.
When was the last time you put a scope on the ISC lines and watched how it works?