OBD2 to OBD1

[waker_mikie]

Im looking to change my ECU to a OBD1. So I can run with out check engine lights. PO removed all emissions and running with about non removable 6 CELs and up to 15 CELs. Once I get it all working right ill be running a Stanza ECU and install the consult port.
1997 d21
Ive looked into it and there's not much info on it..each article has a couple parts, but not all, that need to be swapped out as they are not needed or can't be used with a OBD1 ECU.

So far I need:
Remove secondary O2 sensor
Remove Crank angle sensor
OBD1 Ecu
OBD1 Distributor
OBD1 Front timing cover
OBD1 Intake manifold

Is there anything else? I may replace top the entire harness with the correct harness. Not sure how much different the two harnesses are. Any info is appreciated.

[fbccars924]

You'd be better served to get a reprogrammed ecu from 4x4parts.com, there is the potential to have alot of wiring, software and hardparts you need to get to work together.

[synbiotic12]

^ I second that, I think in downgrading you'll cause yourself some electrical gremlins. Might just be better worth your time to have 4x4parts hook you up.

[waker_mikie]

Now to me that seems almost pointless..all the reprogrammed ECU does is void reading certain signals from sensors. Then you would have useless sensors sitting in your engine bay. With swapping a couple of parts you would have an engine exactly like earlier years. Not necessarily downgrading, because with the OBD1 D21 ka24e, there are interchangable parts from the OBD1 240sx ka24e.

Im just trying to get someone thats done this before and see what they did and what problems they ran into. Not any "could" "might" "i think" problems.

[fbccars924]

It doesn't make sensors useless it remaps the fuel/air and the rev limiter to simplify it. all the sensors remain used. OBDI would render most of your sensors useless being as they wont communicate with the OBDI ecu.

[waker_mikie]

Im not sure if you get what I'm trying to do here...the prior owner has removed all of the emissions, doing that it causes check engine lights, which are all for emissions and things that are not read on obd1. Reprogramming an ecu wouldn't fix that unless you tricked the ecu into thinking that the sensors were there. I could go either direction, buy all emissions parts to put back in or while im replacing the timing chain put an obd1 timing cover and distributor in place of the old. Replace the ecu and possibly a couple of other parts. I'm just trying to figure out if anyone has done it.

[Deerhurst]

I agree with others. Contact JWT or 4x4parts and see if one of their ECUs will do the job. What they do is take yours and flash it for what ever mods you have done. Their basic flash should give a little perfomance and they should be able to clear or eliminate your CEL.

You will also retain your OBD 2 fuctionality.

4x4parts also has a programmer for the 97. It may also be able to clear your CEL.

[waker_mikie]

I dont want obd2.........

[waker_mikie]

Running obd2 has no advantage, and it limits tuning. I want to tune it myself. Not have some company do it for me for an excessive amount of money.

[ahardb0dy]

Just change everything to pre OBD2, you will probably need the pre OBD2 harness, the second O2 sensor can be left in place as the older harness won't have a plug for it anyway.