I'm interested in details of how an EA82 ECU works.

 

Specifically, what triggers closed loop operation, compensations for temperature, TPS modifications to the fuel signal, etc.

 

Does anyone have details on this available, or should I add some sensors to my car & start figuring it out?

 

-=Russ=-

what specific model ECU are you trying to probe?

there are different units depending SPFI, MPFI & turbo early, and later MPFI/turbo

I know the SPFI uses a Motorola Processor similar to the (in)famous MOS 6800 CPU from your Apple II - however as it is an "MCU" instead of a CPU, the pins, and capeabilites are different - earlier SPFI units - from the pre-Loyale cars are black, and have a seperate memory chip that I think holds ~256 bytes of data, it can be erased optically, and there are connectors on the board to reprogram it - later ones are gray, and have no seperate chip, and probably cant be reprogrammed

the long and the short - I dont know of anybody trying to probe the ECUs - but it would not be an easy proposition, as it would have to be in assembly, and you'd probably fry a few before you figured it out.....

Good Luck

 

btw - to my knowledge, there was NO dealer plug-in to get a direct readout from the ECU, all was done through the trouble light

There are test mode connectors that were supposed to plug into *something* that the dealer had. At least that's what I thought. Being there are two modes - test mode, and "u-check" or something like that it seems likely. Who knows tho - I've seen diagnostic plugs on military equipment that the military never bought the diagnostic gear for. We simply never got the goods cause it was too expensive, and in someone's opinion not needed.

 

GD

GD-- the u-check test mode is done by plugging in the green timing connectors and revving the engine over 2k for over 40 seconds. then the ECU blinkenlight flashes a different set of codes from whats stored in memory.

 

i dont know what kind of diagnostic program it runs, but it told me that a couple of tranny gear sensors and the speed sensor were faulty (???) and also that my O2 sensor and my TPS sensor were questionable. never had any CEL, changed the TPS and car has lost more than half her "ghosts"

 

Syonyk: PM bgd73. He has gotten his elbows deeper in the ECU than anyone else ive heard of thus far, and would be able to answer _some_ of your questions im sure.. and he might know where you could get more data. everything that he has said about it has been out of my ballpark.. i know enough about tech to understand it all, but zilch about these ECUs in particular. he apparently is an old skool nerd (ie munches breadboard) AND a gearhead, so i would start there.

GD-- the u-check test mode is done by plugging in the green timing connectors and revving the engine over 2k for over 40 seconds. then the ECU blinkenlight flashes a different set of codes from whats stored in memory.

 

i dont know what kind of diagnostic program it runs, but it told me that a couple of tranny gear sensors and the speed sensor were faulty (???) and also that my O2 sensor and my TPS sensor were questionable. never had any CEL, changed the TPS and car has lost more than half her "ghosts"

 

Syonyk: PM bgd73. He has gotten his elbows deeper in the ECU than anyone else ive heard of thus far, and would be able to answer _some_ of your questions im sure.. and he might know where you could get more data. everything that he has said about it has been out of my ballpark.. i know enough about tech to understand it all, but zilch about these ECUs in particular. he apparently is an old skool nerd (ie munches breadboard) AND a gearhead, so i would start there.

 

I didn't go that deep

I simply burnt a resistor. Ecu is dynamical for all throttle and math programmed. All I did was have good luck with resistor doubting electrical "calmness" due to the fact I have a 2wd gone wild.Assumed no driveshaft really made "stuff" manic.The following photo can be summed up with last sentence in it.( I took a deep breath after reading it.) The rest of ecu and system seems very common, universal, and rather simple, like injector etc.

quick poll...

 

raise your hand if you have soldered componentry onto your ECU (or even inline on a pin)

 

that was my only point

There was a guy a while ago (D-Cal was his name) that said that the mpu in the ecu was very similar to the commodore64 computer and believed that with the right interface he could reprogram it, but didnt have time to do it.

 

Read this

http://www.ultimatesubaru.org/forum/showthread.php?t=49014