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Discussion Starter · #1 ·
I know this has been discussed a lot, but I did a search and most of the topics from March back have been deleted.

I just have a couple simple questions, and would appreciate some help understanding this stuff.

1.) OBD2... if I mod my car, and leave this chip in, is it going to completely negate my mods?

2.) JDM... will a JDM chip plug in and solve this problem? Are they attainable?

3.) OBD1 conversion... I'm sure my tuner can do this (Yes?), but I read that the OBD1 will cause me to lose features on my 5th gen. Which features are these? Are the necessary parts for an OBD1 conversion readily available?

I guess I'm just looking for the best way to solve the OBD2 problem, without doing the battery-backup work around.

I know these questions have been posted a lot. Thanks in advance for any help!

Hambones
2001 Type SH, Silver, stock... for now
 

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OBD2 isn't a chip. Doing a swap from 2 ->1 isn't cheap either. That's about all I can add right now. Other more knowledgable people will probably reply later.

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Mugen front bumper and sides with a combat rear bumper for sale in NJ....talk to me personally. East coaster highly, HIGHLY preferred. Also now for sale Tanabe G Power Medalion for 280 and 18" Racing Hart TypeC5's (Price not decided yet)
 

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You have an SH so you would lose your ATTS and Immobilizer.

Definately not a SH friendly mod.

With an obd2 car, your bolt ons will not be negated, you just wont gain as much hp as a obd1 equipped car.

This is a mod that takes time and effort to do, its not something you just plug in, unfortunately.

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Flavour
98 Base, Black
I/H, pulleys, tb, p&p, cams
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Discussion Starter · #4 ·
<font face="Verdana, Arial" size="2">Originally posted by Flavour:
You have an SH so you would lose your ATTS and Immobilizer.

</font>
'nuf said. Thanks for your replies.
 
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1. OBD2 is the entire ECU and a few other things (secondary O2, fuel tank vent, etc). It won't negate all of your mods, but might hurt them a bit.

2. There is no chip, it's a complete ECU.

3. You will lose your immobilizer and some emissions equipment. If you have an SH, you will lose ATTS, unless you use a Type S ECU.

To do the conversion, you need the ECU, a OBD2 to OBD1 harness (unless you have the ECU connectors), OBD1 distributor with connectors, and some patience!! If you use an OBD1 Prelude VTEC ECU, it's advisable to use peak and hold injectors with a resistor pack.

If you wait a bit, I will probably be selling a 95 Prelude VTEC ECU that has been reprogrammed.

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Billy
North Texas Prelude Owners Group
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since no1 has replied to my other thread yet, i'll ask here.

Also, has any1 tried this obd2 workaround switch that marcucci did?
http://www.ntpog.org/mods/fifth-afc/ecu.shtml

Well yea, just wondering if you tried this workaround. is it that neccessary since we have obd2 ecus? and is it effective at not letting the ecu to learn and readjust the a/f ratio?

-Tony


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'98 Diamond White Type SH:
RS*R Down Springs, Tanabe G-Medallion Cat-Back Exhaust, Iceman Intake, Neuspeed Front Strut Bar, 18" RH Evos D6000 ,APEX-i VAFC, '99 Grille, JDM Fogs, OEM Front Lip (On its way)
 
G

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<font face="Verdana, Arial" size="2">Originally posted by smoothludey:
What is the advantage of having a stand alone ECU?</font>
What exactly do you mean? Are you talking about an aftermarket programmable stand alone ECU?

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Billy
North Texas Prelude Owners Group
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I also was curious about this topic, except I was wondering for a 96 vtec, will converting to obd1 show any noticable gains after modding. And is there any other advatages to this conversion. I would eventually turn to force induction, if that makes a difference.

~SpeedCrazie
 
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<font face="Verdana, Arial" size="2">Originally posted by smoothludey:
Originally posted by 71dsp:
What exactly do you mean? Are you talking about an aftermarket programmable stand alone ECU?

</font>
well, i guess i'm wondering what a 'stand alone' ecu is and why you and sun are doing it...
Because I want to be able to control every critical parameter of the engine (spark, fuel, etc.). I can also eliminate my VAFC with a stand alone (anyone interested in a brand new, never installed VAFC???).

I could write a book about all the stuff that a programmable ECU will give me. Basically, it will give me complete control over the fuel and spark parameters of the engine.

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Billy
North Texas Prelude Owners Group
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Discussion Starter · #15 ·
I noticed in another post regarding Malken's dyno run that he is still running the OBD2 in his car. He posted great numbers in NA mode, so that's reassuring... especially since his car basically has the same mods that I plan to install (minus the NOS... but add cams, springs, and retainers, and maybe a TB and matched intake manifold). phewww, getting excited just thinking about it
woo hoo !!!

it's a disease


[This message has been edited by Hambones (edited May 03, 2001).]
 

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A few additional notes:

- Hey, I've tried my OBD2 backup power mod! Works fine. Right now I don't have the switch in, though, so I won't be able to retrieve check engine codes. In short, this is the same as pulling the 7.5A CLOCK/RADIO fuse that resets the ECU (and the radio!). If you've ever reset your ECU you know that it DOES add allow for more power from your mods. What it doesn't do is allow you to ditch the cat, get rid of emissions components, or a few other items that a standalone ECU or JDM ECU probably will. It will retain all the functionality you need, though, like ATTS or the immobilizer.

- A standalone ECU replaces the factory ECU and at times a lot of the sensors. This is not a mod for the weak; it requires serious hacking of the factor wiring and it will likely be impossible (or VERY difficult) to return to the stock ECU. Setup and subsequent programming will take a shop with some GOOD knowledge of standalones (and perhaps the brand you choose). Not something you want to attempt yourself, unless you're nuts, like Billy.

- OBD2 won't negate mods completely. But it does impair them, sometimes severely. OBD2 also adds more emissions stuff, like the tank purging and secondary O2 that prevents cat converter removal. It's not the method of choice for engine control if you're a serious tuner.

- An OBD1 swap is a pain and costly. You need to source a '93-'95 Prelude VTEC ECU, and this will only work on the base model. Type SH owners have no option other than a Type S ECU or standalone. And there's no real proof that the JDM ECU is really any better...
 

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<font face="Verdana, Arial" size="2">Originally posted by marcucci:
A few additional notes:

- Hey, I've tried my OBD2 backup power mod! Works fine. Right now I don't have the switch in, though, so I won't be able to retrieve check engine codes. In short, this is the same as pulling the 7.5A CLOCK/RADIO fuse that resets the ECU (and the radio!). If you've ever reset your ECU you know that it DOES add allow for more power from your mods. What it doesn't do is allow you to ditch the cat, get rid of emissions components, or a few other items that a standalone ECU or JDM ECU probably will. It will retain all the functionality you need, though, like ATTS or the immobilizer.
</font>
If i do your OBD2 workaround mod, will it lose power to my headunit too? Will i have to readjust my headunit settings evertime i start my car? Hopefully the power is only cut to the ecu.

-Tony

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'98 Diamond White Type SH:
RS*R Down Springs, Tanabe G-Medallion Cat-Back Exhaust, Iceman Intake, Neuspeed Front Strut Bar, 18" RH Evos D6000 ,APEX-i VAFC, '99 Grille, JDM Fogs, OEM Front Lip (On its way)

[This message has been edited by TcT118 (edited May 03, 2001).]
 

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<font face="Verdana, Arial" size="2">Originally posted by TcT118:
If i do your OBD2 workaround mod, will it lose power to my headunit too? Will i have to readjust my headunit settings evertime i start my car? Hopefully the power is only cut to the ecu.

-Tony

</font>
Nope, that's part of the point- put in the switch and you won't lose power to the head unit ever. Toggle the switch, it doesn't effect the radio.
 
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