Converting p12 auto ECU to manual

[93twodoorLX]

Hey guys,

I recently purchased a p12 ecu without doing my research and ended up buying a p12 ecu for and automatic. The issue with this is that upon warming up to normal operating temperature, the idle of the car tends to surge slightly. This can be rather annoying. Once the car is up to temp the problem goes away. So the only thing we are changing is preventing the surge that occurs on initial cold startup.


<<<<<DISCLAIMER>>>>>

THIS PROCEDURE REQUIRES A BASIC KNOWLEDGE OF SOLDERING ALONG WITH THE PROPER TOOLS. I SHALL NOT BE RESPONSIBLE FOR INPROPER USE OF THIS INFORMATION.

soldering is not too hard. youtube has many instructional videos of how to do so.

HERE IS A THREAD ON HONDA-TECH THAT IS SIMILAR TO WHAT YOU DO ASIDE FROM THE LOCATION OF THE RESISTORS BEING CHANGED. http://honda-tech.com/showthread.php?t=2969571

look through that thread and get the general idea of what to do then look at this picture

A jumper wire could be something like a paper clip bent in a U shape inserted through the holes and soldered in



This applies to all ECUs that share the same board (P11, P12, P13, P14 and P39)

this is my first real attempt at making a write up to help out. I havent found too many threads around concerning the p12 ECU. I just hope this helps.

cheers and good luck

-Sean

[hotrodj]

Or you can send the ecu to me and Ill do it for $20 lol

[Shadow1]

or you can just clean out the IACV and adjust it. then you don't have to re-solder anything.

good information. not really needed unless someone wants to go into the ECU. i had a p12 ECU from an auto and didn't need to redo anything. no idle surge. no warm up issues.

[Losiracer2]

yeah i'm getting this on my auto P12 i just found the other night. Only when its cold it idles from 1500 to 1800, but a min later, its just like a manual ecu. I'll probably want to do this as when winter comes the problem will definitely linger around for longer since right now, its 110 outside so no warm-up necessary really.

[93twodoorLX]

or you can just clean out the IACV and adjust it. then you don't have to re-solder anything.

good information. not really needed unless someone wants to go into the ECU. i had a p12 ECU from an auto and didn't need to redo anything. no idle surge. no warm up issues.

I dont have a fast idle thermo valve on my h23 plenum. it is deleted, so i cant adjust that.
tried the IACV. hoped that was the problem too. it wasnt. even tried a brand new IACV. didnt work. but once i did this change. the problem STOPPED. perfectly normal now. just be warned everyone that this is a delicate procedure, so take caution. But if you've got the balls to open the ecu up and take the risk, it can be worth the effort. just be careful.

p.s. wasnt sure if i even should put a new thread up considering there is a thread that relates to this somewhat somewhere else on here. However when i called deevergote and talked to him about it he said i should put it up on the board just to have more info on here and some clarity.

cheers mates

-sean

[Losiracer2]

I just wanted to add, I did this today to my AT P12 and my idle fluctuation at cold start=up has gone away.

It now idles at a rock solid 1500. Also when in neutral, I was at about 850 before, now its at a steady 750.

It helps to use an O-ring pick that's curved to help lift up the jumper from RP11 and tweezers along with a jewelry flathead screwdriver to help push the jumper back into RP12.

I bought all the tools at harbor freight:

-Orange box for jewelry screwdrivers: 3.99
-O-ring picks comes in a set of two: 2.99
-tweezers: had at home

I also used my Hakko 936 adjustable temp soldering station. It has a slim chisel tip to make pinpoint soldering easy. I set it on the max setting at 900 degrees.

[93twodoorLX]

Im glad to hear that your problem has been taken care of. it definately gives you peace of mind knowing it is in there right.

also thanks for posting up some confirmation that this modification does indeed work. I hope this sheds some light on a problem that future cb7t members may have.

cheers

-sean