Edit: title should say 95 VX with Z6 MOTOR HELP!

Here's what started the fiasco: I put a d16z6 motor in a buddy's 95 VX hatch and we kept the VX trans (attempting to get max MPG for commuting). I converted the 5 wire O2 to 4 wire per the writeups found here on HT (thanks a lot!) and plugged in a stock, unchipped, unmolested, P28 ECU. The O2 is a new Bosch purchased at O'Reilly's. Ignition timing is set correctly (triple checked, service jumper and all). I used the EX exhaust manifold, so there is not a cat currently on the car. Everything else is STOCK otherwise. New plugs, wires, thermostat, timing belt, water pump also on the car (and YES it's timed properly).

Here's the problem: When driving for long periods of steady speed the CEL will come on with a 'soft' O2 code (it resets with ignition cycle). Also, if you downshift (to pass) or just try to accelerate moderately aggressively the CEL (again, with the 'soft' O2) returns and the car loses power almost completely! Not good if you're trying to merge into highway traffic.

Here's why I need help: I've checked every sensor on the car, both for connection and proper readings per the service manual (Helm). I've triple checked the wiring for the O2 conversion. I did a compression check on the motor (220-225 all across!). The car drives fine except for the CEL light plagues my dreams!

EXPERTS NEEDED! If you have experienced this or something similar please share. I need to get this fixed, it's making my buddy nervous during his commute.

Thanks in advance to anyone that can help.

 

Really need some help on this. bump.

 

have you pulled the code?
i have a soft code as well but can retrive it if i don't turn the car off...

 

hey, what 02 conversion diy or post did u use can u post it ?? and mabey u did that wrong and thats messing u up ?

 

it's just O2.


krysted- I searched through several of them and found the method that was common to more than one. I would think that if I had the O2 wired wrong it would throw the code immediately upon starting, not just when accelerating.

 

can u please post which one u did as i have a question posted and im getting 100'ds of different answers , please let me know how u did it or send me the link, thanks and pleaseee

 

have you tested your O2 sensor?
just to make sure it's good?

i don't think that's the problem...

what type of wire connections did you use?
the O2 is a shielded wire so a splice in the wrong area could be the problem...

that is a long shot...

have you tried a different ECU?

 

but the CEL only comes on sometimes? Because this happens to me too and I cannot seem to fix it. I hope after I do my swap this will never happen again.

 

O2 sensor is Brand new. I know that it's possible for it to be bad out of the box. the thing that is lurking in the back of my mind is that it's not an OEM O2...it's a Bosch replacement.

I made a conversion plug from an old harness using the O2 wires and the distributor plug (92 Prelude h23 distirbutor plug happens to be the match to the 5wire O2 plug!). I did use crimp butt connectors on the conversion harness.

haven't tried different ECU, but again I would think that an ECU would 'code' immediately, not just under load.

 

do you have the means to try a diffrent ecu? like borrow a friends?
i would try that first

the crimp connectors are a bad thing
remove them and solder the wires the correct way

just trying to rule things out one at a time till you get to the source

 

and i have used bosch O2 sensors at work for a wile with no problems to date
that is why i said that's probibly not the problem

 

I guess that's what I'm down to really. I'll have to remove the butts and round up another ECU.

I agree with you on the Bosch, but at this point I have to rule out everything.