OBDII Troubles and questions - Honda Prelude Forum

lildrgn · 08-14-2002, 07:56 AM

Greetings,
I have a 96 Prelude Vtec, which is OBDII. A friend of mine (JG LUDER on here) was going to advance the timing, then found we could not. (the third bolt, the bottom one, is not slotted). Then we heard that the OBDII would not let us advance anyway. Then I heard that I can not get my ECU chipped.
So this is becoming one big nightmare.

My question(s):
1) Can a distributor from a 93-95 (OBDI) Prelude vtec fit on my car so we can advance the timing a bit.??
2) Can I get a OBDII to OBDI harness and get an ECU from a OBDI Prelude Vtec?
3) Will this cause any problems?

Satan_SRV · 08-14-2002, 08:26 AM

Quote:

Originally posted by lildrgn
Greetings,
I have a 96 Prelude Vtec, which is OBDII. A friend of mine (JG LUDER on here) was going to advance the timing, then found we could not. (the third bolt, the bottom one, is not slotted). Then we heard that the OBDII would not let us advance anyway. Then I heard that I can not get my ECU chipped.
So this is becoming one big nightmare.

My question(s):
1) Can a distributor from a 93-95 (OBDI) Prelude vtec fit on my car so we can advance the timing a bit.??
2) Can I get a OBDII to OBDI harness and get an ECU from a OBDI Prelude Vtec?
3) Will this cause any problems?

1) Yes and no. You can't have an OBDI dist and an OBDII ECU cause it will be trying to control it.
2) Yes (It's the same engine and injectors as 93-95)
3) No

I have a 96 VTEC as well. I have a OBDI P72 GS-R ECU (Chipped), and an OBDII->OBDI adapter being finished this weekend. I'm not going to bother to change the distributor...YET, unless I run into problems. Since it's already chipped I believe the ECU should have advanced timing in the ECU, just my base timing wil stay the same.

I'm posting my results on Honda-Tech this weekend. I'll keep you posted.

lildrgn · 08-14-2002, 10:56 AM

Where did you get your ECU and how much.. I thought about doing a P72 and a Hondata stage 2

but wonder if it would be easier just to find a OBDI prelude vtec ecu(chipped) and a harness

Satan_SRV · 08-14-2002, 11:02 AM

Quote:

Originally posted by lildrgn
Where did you get your ECU and how much.. I thought about doing a P72 and a Hondata stage 2

but wonder if it would be easier just to find a OBDI prelude vtec ecu(chipped) and a harness

I got my P72 off ebay for $200 shipped cause I e-mailed the guy an offer right when the auction opened and got lucky. It's not one of those JUN/Skunk2/Mugen standard ridiculous chips but it should be good, apparently H22a tuned..who knows.

If you are going Hondata, an OBDI P13 is a waste. You can't do hondata stage 2 with it, they can't decode it. However, someone with TechTom tools can chip a p13, but you have to go in everytime you want it remapped, and not a simple as Hondata. That's why they recommend the P72 as it still has Secondary IAB as well as knock sensor.

As far as I know you can run an OBDI ECU on the OBDII distributor..I'll let you know this weekend. But if you want to adjust the timing manually you will have to swap the Dist as well.

vile10 · 08-14-2002, 02:08 PM

is it the same apply to H23? cause i am thinking of doing the same thing? all i needed are ECU w/ chip and the adapter? or i need more? where you got your adapter and how much?

SikRedRX-8 · 08-14-2002, 06:08 PM

You can unbolt the bottom one all together and use the two top bolts, We did this to a friend of mines and there is no problems what so ever. Make sure the top two are tight though.

Satan_SRV · 08-15-2002, 02:16 PM

Quote:

Originally posted by vile10
is it the same apply to H23? cause i am thinking of doing the same thing? all i needed are ECU w/ chip and the adapter? or i need more? where you got your adapter and how much?

My adapter was custom made...my friend may start selling them soon. Cheaper than any one you can buy off the shelp today.

96LudeVTEC · 08-15-2002, 06:47 PM

Where can I get the adaptor for the OBDI ECU??
How difficult is it to install?, just take out the old ECU and then plug in the new ecu with the harness and replace the distributor as well?

hmmm I wonder if I'll pass emissions in TX? OBDII connector probably won't report anything after the ECU swap right?

Thx

Aldo

vile10 · 08-16-2002, 06:44 PM

is the adapter and a OBD I ecu all i need for the conversion? do i need anything else?

marcucci · 08-19-2002, 02:55 PM

Aldo, you will flunk emissions testing in TX like a skunk. For OBD2 vehicles, they connect to the OBD port and request info from the ECU. Since you won't have an ECU that will report that- you will fail. They will give you a timeframe to get it fixed, but w/o swapping back, you won't be able to pass.

Best bet is to leave it be- unless you can get a harness and figure out how to swap it back with little effort (IIRC there is no way!).

vile10 · 08-19-2002, 07:27 PM

is swapping back a big hassle? i thought we're only swapping the ecu and the adapter

Satan_SRV · 08-20-2002, 08:11 AM

Swapping is a piece of cake....I just had a harness made. I can swap ECUs between dyno runs it's that easy. Just hang onto your OBD2 ECU for emissions testing and you'll be fine...it's like 3 plugs to swap it...and if you leave the bolts off the cover to the ECU panel it's even easier.

Absolut · 08-20-2002, 01:26 PM

I wonder if you could set up a big rotary switch and have 2 ecu's in the car, one tuned for regular driving, the other for racing.

You could pull up to a light, see a 5.0, turn off the car, flip a switch, restart the car and voila, you have a race ready ecu and nobody is the wiser. After you kill the stang, you could revert back to the normal ecu for better mpg and passing smog etc etc