Auto Ecu

[dmonic1]

(1)does anybody on here know how the the auto trans ecu communicates with the engine ecu.

(2)is there a trigger wire to signify an up shift or is there a series of information past to and from each ecu during the process of a gear change.

(3)does anybody by any chance have the pin outs of the auto ecu. i have the engine ecu pinouts but just need to find out how the two ecu's communicate. i have a friend at haltech who is going to try and determin if he can use the rpm based ignition retard flat shit map in nissan automatic vehicles. the map isnt load dependable but is programable at intervalls of 500rpm and will control ignition timing if a triger signal can be found.

there "could be" a new range of haltech ecu's coming out in the near future that will be an advancement in piggy back computing. instead of being wired into the loom before the ecu and altering or bending the signals ( dfa, sitc etc )from the standard sensors like our MAF signals. the new ecu's will also be able to be wired after the standard ecu and catch the ignition and injector signals and add correction values to them. allowing for full control of all engine requirements while still leaving the standard ecu in place to control procedures that are to hard to dupilcate when using a stand alone ecu.

i havent had my stagea long but im sick of reading about how everone has given up and put the idea of having a properly controlable ecu in an auto in the to hard basket. if i have to go and road test my car with a test light on or muli meter on every wire on the ecu i will but im hoping someone has the wiring diagrams somewhere.

But i didnt tell any of u guys about this. hint hint as its just hearsay atm

thanks heaps if u got this far as all ur help will be appreciated. im not going to rest until i get this or something to work so i can give us auto guys what we want.

Cheers dave

[Sydneykid]

This is the ECU pin out schematic that I used;

http://members.iinet.net.au/~jay77/R34ECUpinouts.pdf

The engine ECU outputs/ inputs for auto trans are 34, 35, 38, 39, 40, 41, 52, 64, 65 and 66. Pin #52, #65 and #66 are the data transfer input/output for the auto trans, so they are the most likely.

My understanding is limited, but I have been told that the auto ecu signals the engine ecu when it is about the change gear. The engine ecu looks at the various parameters (rpm, kph, what gear, throttle position, engine temperature, AFM voltage etc) and then chooses an applicabe amount of igntion retard/cut from its 3 dimensional map. The mapping is supposed to be very complex to cover all circumstances (varieties of inputs).

My understanding is that Apexi looked at duplicating the mapping in their Power FC and found the cost to be prohibitive (ie; no one would pay the price). They did do it for Toyota autos, but they have the mapping in the auto ecu, not the engine ecu.

The Haltec piggy back scenario you describe is much like the EManage, HKS FCon and several others. Nothing new there.

Cheers

Gary

[Tangles]

cheers Gary

that above info (pin #'s) will be very helpful when I have the r34 gtt Pfc tuned at end of summer