Onedopehatch

So I bought this 92 civic cx from a buddy of mine for a daily driver. The motor and Trans had been swapped by the guy before my buddy. It gets around 35mpg combined (city/highway) and when I first got it I thought it was great gas then I started to look and it seems that the z1 should be getting well over 40 mpgs, so I started digging and looking through car more closely and found that it's running of a p05 but shouldn't it be operating off of a p07? Vtec isn't hooked up because It doesn't have a vtec ecu doesn't it mean it doesn't lean burn as well to save gas? Would swapping to a p07 fix the gas issue? I've done all of the maintenance on it and tire pressure and such. Any help is welcome, thanks

jlk16188

You need the proper ECU for the Z1. You also need the wiring done properly for the 5 wire wide band O2 sensor. this engine will not run in lean burn or vtec without it being wired correctly and without the proper ECU. The Z1 gets worse gas mileage than a normal d series motor when its not in lean burn mode chugging around town.

The Z1 is a very finicky motor and has to be set up correctly to make any decet MPG numbers. You are lucky you are even getting 35 MPG

My VX now gets close to 60 per tank but has taken a lot of work to get it back into the running condition it left the factory at.

Onedopehatch

Is the proper ecu the p07? Or am I mistaken? And the wideband O2 I don't think I have either. I've been searching for the right ecu for it around where I live and haven't been able to find one, I honestly haven't even seen another vx around here so I'm probably going to have to order that from somewhere soon

jlk16188

the P07 is correct but you need to make sure you get either the california one or the 49 state one. You must have a 5 wire wide band o2 sensor and dont be sticker shocked. The o2 sensor alone from Honda is over $400. You can get aftermarket ones for around $200 but they dont run on the correct voltage. You also need to ensure your car is wired for the 5 wire sensor.

Get on ecomodder.com. There realy isnt much help for d15z1's on honda-tech.

Onedopehatch

Alright, I'll go try over there. Thanks for your help!

jlk16188

google is your best friend in this case as well. The info for this engine is spread all over the internet and not neatly packaged into threads like most other topics on honda-tech.

I did tons of reaserch on this trying to rewire my VX back to stock (my VX came wired for a K series engine but had the original d15z1 sitting in the bay not hooked up when i bought it with a full wire tuck)
I had to undo all of the wire tuck and rewire most of the car. I ended up with a hybrid between a VX and del sol engine and body wire harness

Onedopehatch

Wow... Sounds like a good time lol. Mine was from the factory a cx and I'm pretty sure it had a b7 in it and that's what's it wired for so I'm going to have to do a little wiring myself

jlk16188

unless you have some strange desire for the D15Z1, i would suggest taking it out and selling it to buy a replacement D series non vtec motor. The ecomodding world drools over the D15Z1s and you could probably make a pretty penny on it and have cash left over after buying a replacement CX or DX motor and not have to worry about the ECU, o2 sensor or wiring headaches. any CX or DX motor will drop right into your car with no modifications or wiring and will be pretty cheap

Onedopehatch

So, what are you saying its worth? The z1 that is

jlk16188

depends on the mileage and general condition, if it includes the VX/CX long geared transmission and has about 100K on it without any known issues it could be worth $600-700 depending on the buyer. a DX motor and transmission can be bought around my area for about $2-300 for the complete swap.

Your CX transmission alone will sell to ecomodders for close to $200 if its in good condition with no grinds.

But if that motor has over 200,000 mile on it or issues with it then obviously expect less

Onedopehatch

Alright, thanks!