The story.. i picked up an Automatic 89 crx dx with a overheated d15b2, decided i would do the z6 head mini me swap since the head was off and most likely junk anyway. now the heads all done timing belts done, down to a list of misc small parts i need to get and two somewhat expencive ones(considering the car was just 150$). I need a z6 dizzy and an Automatic p28 ecu. i have a manual p28. so now my question... is there any other options for ECUs i can use, also is the z6 dizzy the only one that will work, and stupid question but would the car even drive if i were to use the manual p28 ecu? reason im asking is im striking out with finding these parts here in ND and a new z6 dizzy is $195 + an $88 core that i dont have... thanks for the help.

 

I have seen plenty p28 automatic ECUs on ebay that have been "converted" to 5-speed - Mine is such an animal works just fine, so there is a chance that someone has done the opposite conversion. In any case, you shouldn't have a hard time finding and inexpensive ECU of your preference in the junkyard.

As far as the dizzy goes, you'll definitely want to pair a z6 dizzy with your z6 head. Make sure that you mate it to a EDB1 ECU (p28 as you mentioned) as the z6 dizzy is also EDB1.

 

yea ive seen the auto to manual "conversion" but i think i read somewhere that to do a manual to auto involves adding the two resistors and a few other components that im not sure where to get or the work it would take. but thanks for the info, very much appreciated. guess ill dig a little further at the local yards..

 

For USDM OBD1 ECUs:
Remove RP17 and install a jumper across RP18.

For Jdm Pr3/Pw0 ECUs:
Move the jumper from R68 to R67

For JDM OBD1 ECUs:
Remove R17 and replace RP18 resistor with a 1.4k resistor

 

This would be to convert a manual ecu to an automatic?

 

My bad - sorry. That was auto to manual.
I read your posts but it didn't click that you actually want to keep the auto.

For your swap it might actually be better to go with the manual ECU.
The car will drive, but the torque converter on your 89 CRX won't lock ever.

The auto P28 has two lock up solenoids that are totally not compatible with the 89 auto tranny. You will throw codes constantly and the torque converter won't lock up.

So lesser of two evils - neither are compatible with your tranny and one of them throws codes.

Not too long ago there was a guy on here named 'BoRiCuA' trying to do this swap.
He has spent $$$$ into researching it, but the last I saw of his post there wasn't a solution and he gave up on trying to OBD1 it.

 

ah i was so excited that it was that simple. as long as im understanding your correct i think ill try and run the manual ecu, and start collecting parts to do a auto to manual (transmission) swap. the torque converter only locks up in overdrive/drive when ur maintaining speed correct? for fuel economy? so with it not locking up it should not effect in town driving which is 99% of what i would be using it for...?

 

Greatly appreciate this info BTW,

 

alright, so maybe in gettin confused. my car is 0bd0 right? i got a z6 dizzy whitch is obd1? z6 injectors obd1? p28 ecu is obd1? with wat i have i need a 4 wire o2 sensor? i dont need i resistor box? do i need to get a obd0 to obd1 conversion harness? if i do get a harness do i need to do the dpfi to mpfi conversion first or is that part of the conversion harness? sorry for the rookie questions

 

where are you located?
i have a automatic p28 and i need a manual
Maybe we can trade?

 

Your car is obd0 now.

the z6 distributor is OBD1. you WILL need that if you run a P28 or P28 compatible.

Z6 injectors are high impedance. You can use those without a resistor box, but if you use OBD0 injectors, you will need a resistor box. It must be done in a pair. OBD0 injectors require the resistor box, OBD1+ injectors do not require it. The OBD0 choice is more common and popular, as the DSM 450 upgrade is then plug and play.

You will need an OBD0 to OBD1 conversion harness, but that will only work AFTER you do an MPFI swap correctly. I would do the DPFI-MPFI conversion first and make sure that works, then swapping to OBD1 is easier. You still need to add wires for the 4 wire 02 after you do the OBD1 swap, though your conversion harness should have the wires already integrated.

I guess you could trade this guy, but running the Auto ECU will just give you an auto trans lockup solenoid CEL. There is a certain value resistor you can substitute to get rid of the CEL, but you will get worse gas mileage without the lockup activation.

 

Either way you can manually or vacuum actuate the lock-up solenoid as an alternative to the ECU.