01 prelude sh obdII P5P ecu

Hondata model coverage & ECU application questions.
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aglude
Posts: 7
Joined: Mon Oct 28, 2002 10:07 am

01 prelude sh obdII P5P ecu

Post by aglude »

ok, here's my deal. I have an 01 prelude sh and I'm looking into installing a JRSC kit. I read through most of this website looking for info about this set up, and most recommendations are to use a P72 ECU and convert to OBDI. What I'd like to know is if there's away to program a PROM for my P5P OBDII cpu and still retain the use of my ATTS? I keep getting mixed signals when talking to people on other boards. Some say that you can buy PROM chips at like $150 to $200 a pop, and write the new ignition and fuel map tables (I understand the whole EPROM vs. PROM thing). Please advise, thanks. :)
whoojong
Posts: 46
Joined: Mon Sep 30, 2002 12:54 am

Post by whoojong »

what you are talking about is not a hondata, Hondata only works for OBDI. You can reprogram your chips but it will not be mapped for boost like the hondata can be, and likely the fuel maps that will be burned onto the new "chips" won't be good for your car.

Whoojong
aglude
Posts: 7
Joined: Mon Oct 28, 2002 10:07 am

Post by aglude »

are you hondata staff?

doesn't the hondata system reprogram the ecu to deal with a boost sensor, and adjust the fuel maps on an obd1 ecu? so if that's the case, why not add a boost sensor to the p5p and remap ignition and timing to deal with boost. or figure out how to program an obd1 ecu to control the atts unit.

either way, I want my atts, and I want an ecu to control a boosted engine properly. any other solutions besides hondata that might do this? when will hondata have this solution for me and others?
whoojong
Posts: 46
Joined: Mon Sep 30, 2002 12:54 am

nope...

Post by whoojong »

OBD II is a bit more complex then the OBD I, therefore you can't just "add" fuel maps for boost. The entire ecu has to be decoded in order for something like that to happen, and that's just simply not profitable. As far as programming atts, from what i understand, the OBDI simply does not have the capability to control ATTS. ATTS is specifically a SH feature and hence there is no controller like it pre-97 which could be adapted both cheaply or profitably. and you're probably not going to see one. Also there is not stand alone system which will control ATTS, so you're pretty much SOL if you wanna keep it. You'll just have to keep using piggy back systems.

Whoojong
aglude
Posts: 7
Joined: Mon Oct 28, 2002 10:07 am

Post by aglude »

ok, here's a for instance. since only the P5P OBD2 ecu can control the ATTS unit, what if all the sensors that are needed to control the ATTS unit are wired into the existing OBD2 ecu, and a seperate hondata programmed obd1 ecu is controlling the rest of the engine?

anyone know of another company that is willing to decode the P5P obd2 ecu and reprogram it?
aglude
Posts: 7
Joined: Mon Oct 28, 2002 10:07 am

Post by aglude »

anyone?
pills_PMD
Posts: 165
Joined: Sun Aug 18, 2002 6:07 pm

Post by pills_PMD »

it has probably never been done. it souds logical... it would take a lot of wiring i'm sure... are you up for it??
prelude2boost
Posts: 1
Joined: Wed Dec 11, 2002 4:16 pm

Post by prelude2boost »

aglude
I have a 2001 prelude VTEC with the JRSC. I want the Hondata ECU but I don't want to swap ECUs, reinstall the JR EMS, change injectors and reinstall the fuel pressure riser . Thats way too much work!

I just wish Hondata would program Prelude OBD2 ECUs.
aglude
Posts: 7
Joined: Mon Oct 28, 2002 10:07 am

Post by aglude »

pills_PMD: not really up for it just yet. it would seem to me that if the similar inputs are hooked up to two ECU's (assuming limited current draw or other signal degenerating issues), the Hondata OBD1 ecu could control the engine while the stock P5P ecu could control the ATTS unit. I'm just not a fan of Jackson Racing's fuel management system. It's based on increasing fuel pressure, and over driving the injectors. Doesn't seem like fine enough control for me, and I'm quite particular about perfection. thanks for the input :)

prelude2boost: with my above comments said, have you had any detonation problems in AZ? I'm actually in Tempe. I met a guy at Firebird the Thursday night with JRSC in his prelude. Might you be the same person? I'll look into those piggyback units, but if the hondata people are listening, I'd still like the option of using the hondata system and keep my ATTS!
Carchitect
Posts: 82
Joined: Thu Sep 19, 2002 11:14 pm
Location: Dallas/Ft.Worth

Post by Carchitect »

The prelude ATTS is a system that involves digital communication of the ecu and the atts unit. The system was designed to allow improved vehicle by utilising sun gears within the atts differential to allow for gear gearing the wheel on the outside of the turn to spin faster than the inside if the turn. This phenomenon is very similar to rowing a paddle boat. However, in order to control the vehicle from tearing the differential out the atts unit digitally communicates to the ecu to retard the ignition timing. This digital communication system is not present on the ODB-1 ecus.

However, if there is a market for it I'm sure Hondata could spend some time to fiqure out a method. Having the system either communicate to the hondata box to retard the ignition (if its even possible) is a possibility. Or over ride the signal regarding the ignition retard request and send the confirmation signal back to the atts unit even though the ignition table wasn't altered. There maybe other options as well that I can't seem to bring up of the top of my head.

Joe.
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