SS Auto Using 5 Spd ECU? - Honda Prelude Forum

Gerhard · 02-20-2005, 01:32 PM

Ok,

This may sound a little stupid...

I understand that the P5M ECU in the 5 Speed Prelude is has a more agressive fuel map than the Auto P5M.

I've recently tried converting the Auto P5M from my 5th Gen to Manual operation by moving the RP13 000 Ohm resistor (jumper basically) to RP14.

The appears to stop the Auto P5M ECU from needed to speak with the TCM (Transmission Control Module).

So, here's my question:

Is it likely that ALL P5M ECUs come with the ability to work with an Auto transmission?

Furhtermore, if you were to perform the reverse operation on a manual P5M (RP14>RP13), what is the likely hood that the Manual ECU will drive the auto tranny?

Wouldn't it more desirable to get a little more power out of Auto base model with a better fuel mapping provided by the manual ECU?

Does anyone know if this is possible, been tried, improbable, etc??

Gerhard

sharkcohen · 02-20-2005, 05:33 PM

Quote:

Originally Posted by Gerhard

I understand that the P5M ECU in the 5 Speed Prelude is has a more agressive fuel map than the Auto P5M.

I've read this many times, I've never seen any evidence for it, I don't believe it.

Gerhard · 02-20-2005, 06:26 PM

Quote:

Originally Posted by sharkcohen

I've read this many times, I've never seen any evidence for it, I don't believe it.

I'm not certain that I do either... but that's what's "floating around" here and Honda-Tech.

The question remains:

If you take a manual ECU and jump it from RP14 to RP13... does it the manual unit work with the Auto tranny?

sharkcohen · 02-20-2005, 07:15 PM

I'm not sure, but alphajesse would know for sure.

alphajesse · 02-20-2005, 10:04 PM

I don't know for sure in a 5th gen, but the maps in the P13 are identical from auto/manual.
This is true for the commonly chipped ECUs as well (p28/30/72.)
The jumpers mereley tell the ecu if it needs to talk to an auto tranny or not. The software mereley has a hook to read the jumper config, and reacts appropriately for the hardware config.

My thought is that this would be a waste of time to do. I really doubt that the p5m is any different from the others.

Gerhard · 02-21-2005, 05:32 AM

Well, this is important because it means that after your work at PGMFI, that the Auto ECU's are fairly valuable again!

You just move the jumper, and all of your problems are solved... and there is no performance hits.

RoadyRacing · 02-22-2005, 07:59 AM

Hey Guys... since your in there jumping wires... I have a question. Is there a work around that tells my 98 Auto SS NOT to down shift? There are times that I want it even though it thinks differently.

Gerhard · 02-22-2005, 09:29 AM

The answer is that it may be possible to edit the shift points in the TCM (Transmission Control Module).

However, I've never seen it done.

kotetu · 02-24-2005, 09:09 AM

Roady, just put it into auto-stick mode. Then you have to take care of it. Hmm though as I recall, it will still downshift when you are approaching a stop.