okay so i know this has been beat to death. and theres a good amount on it but theres nothing that is exaxt. im going to running a t25on my auto crv. im going to run 2 ecus. my oem one is the 37820-PHK-A53. im getting a ecu that was tuned with the exact same set up obd1 (from a friends car he sold me everything for a good price) so the oem ecu for running the trans. the obd1 ecu for running the motor. the answer im looking for is how do i go about wiring these together?

this is the oem ecu. which one of these controlls the trans?

 

and does anyone know where i can find the pinout for the 37820-PHK-A53 ??

 

Sorry to burst your bubble but, even if you both have b20's same exact turbo and injectors, an auto crv will see rpm/intake pressure combinations the manual setup would never see. As a tuner I wouldn't even start with that as a base to tune from.

Now, on to your question since I have put a lot of thought into this but have yet to actually practice the idea.
The obd2 ecu can't see boost under any circumstances. You will need 2 separate map sensors(one for obd1 and 1 for obd2). The obd2 sensor will need to be mounted to a "missing link" from Synapse and the obd1 sensor seeing vac and boost.

Both ecus should be able to share tps, ect, iat, cyp, ckp, o2, tdc, and the vehicle speed sensor.

You will need 4 led lights wired to the obd2 ecu for injectors. The ecu will throw a code if something isn't there.

Now the fun part, you gotta look up ecu pinouts for both ecus to figure out how to wire that all up. Ideally I'd get an obd2b-obd1 conversion harness and an obd2b extension harness, wire those together appropriately, then you can just plug that whole mess into the car and not hack up your stock wiring.

The only thing I feel unsure of is, the signal to the igniter from the obd2 ecu. I have a feeling you will want that to not go to anything so the stock ecu doesn't advance more than the obd1 ecu, plus getting multiple plug firings in the process.

 

what does that obd2b extension harness look like? can anyone help me on this?

 

It just has obd2b plugs on both ends. One end goes into the ecu, the other has the ecu plugs so the harness plugs in. You could also search for a vafc plug n play harness for obd2b to cut up for the project. They are aroubd $100+ an obd1 conversion harness for $30-ish. You will have $150 or so into it.

 

http://www.ebay.com/itm/OBD-Lines-Harness-One-Point-2-Conversion-Line-OBD2-Extension-Cord-Car-Cable-/190993246247?pt=US_Lighting_Parts_and_Accessories&hash=item2c7815a827
or

http://www.ebay.com/itm/OBD-Car-Diagnostic-Line-Harness-One-Point-2Conversion-Line-OBD2-Extension-Cord-B-/111206880920?pt=LH_DefaultDomain_0&hash=item19e4725698

 

Has nothing to do with the diagnostic port. It goes between the ecu and the wiring harness

 

Haha yea That's what I thought. I was confused when the diagnostic plug popped up in the search

 

do you think ill be okay running a td04hl 15t with stock internals on the stock wastegate pressure??

 

Should be fine. B20's have no problems at 250whp stock. You won't be near that

 

Wouldn't it just be easier to run a primitive setup for auto trans vs doing all of this? Running either an FMU setup or AFC Hack would make life a lot easier...being that it's automatic to begin with anyway.

 

I always recommend a piggyback fuel controller in these situations, but I'm not gonna talk someone out of doing something the right way. Double ecu's have been done before, it can work and will give the most control.

 

do you guys think i should get a 3 bar map sensor for this build?

 

your not boosting more than 14psi, i dont think you need one... my first set up was less 300hp and i didnt
even change into a 3bar map sensor...

good luck!

 

With an untouched stock auto tranny, you have no business maxing out the stock map sensor. There are no tuning options that will allow the obd2 ecu to see boost at the map sensor.

If you do the dual ecu, you will need a second map sensor so, getting something that reads higher than stock wouldn't hurt, but if you are anything like me you have stock sensors laying around. Free>$$ any day when the free option is adequate.

 

im a little confused. how do i rig it up with 2 map sensors??

 

One with a synapse missing link to block boost pressure to the ecu controlling the tranny and the other wired to the obd1 ecu being tuned

 

OP if you are having a hard time understanding the basics when they are being spelled out for you then either take it to a shop and pay the coin or just abandon the idea. This is obviously over your head man.

 

Its not hard to do but you need the repair manual to find out what sensors the transmission requires to help it shift smoothly. Go from there first, there should be a diagram that tells you what the ecu looks for to help it shift.

 

im fine with everything now i wasn't sure if i needed the missing link of the obd2 ecu tho i thought i did but was not sure.

 

What missing link are you talking about? when running a dual ecu one controls the engine and boost while the other controls the transmission. There will be some wires that will need to be share between both ecu's and those wires need to be sought out by using the repair manual.

 

Tony, if you don't know what a missing link is then you won't be much help to this guy. You need OEM FSM to get the information required. Repair manuals don't have enough information to be of any use.

 

Actually it does. Hearing this from mean you either failed in trying to do it, or have never done it.

 

I have done it and just used pinout diagrams. It is not hard at all. You two are just clueless.

 

Coming from someone who hasn't offered any advice but to steer him away from something so easily done....