D15Z1 swap (questions) - Fuel Economy, Hypermiling, EcoModding News and Forum

BBrown7888 · 02-16-2014, 09:22 AM

I put a D15Z1 in my 90 CRX and have not been able to get it running right. It was throwing a code for the o2 sensor and since this motor has the 5 wire o2 sensor no company makes a direct plug in ECU adapter so I had to work with what I had. I found what I thought was a good diagram on google for the ECU pin layout and re-wired my harness and added a few additional wires for the extras on the o2 sensor and tried that but now my CEL is solid and will not flash codes.

Long story short, I'm giving up. I don't have time to fuss with this, I'd rather just pay a shop to do it right one time and be done with it. The shop I've talked to says that it will be much easier to just use a wide band o2 sensor and tune the ECU to work with that. I've stressed to them this motor is for fuel economy, not speed and they still say that is the best route. And they also say they will bypass the EGR valve when they do the tune.

My questions are...

1) will a wide band o2 with a proper tune really get me the same fuel economy that my stock 5 wire one will?

2) will bypassing the EGR system hurt my motor or fuel economy?

3) where can I buy a wide band o2 sensor? They guy is going to charge me $240 for the sensor and installation and I have the tools to do this in my garage.

Superfuelgero · 02-16-2014, 10:57 AM

1- no, more than likely the afr range will be too low.
2- yes, increased pumping loses, plus the ecu is mapped (fuel & timing) for it
3- what ecu? If P07, the controller is in the ecu. The o2 sensor is 120-240 itself for the correct ngk.

Jakins · 02-16-2014, 02:28 PM

Yah Bypassing the egr is a bad idea I think. I would either keep trying to do it myself or get them to do a stock set up. Make sure their tune will include lean burn.

slownugly · 02-16-2014, 03:00 PM

Aftermarket widebands do control and allow for tuning very lean afrs (without egr too) but you are going to be changing the entire ecu to a vtec enabled and custom chipped/tuned ecu. Not very cost effective. Can you post a pic of the splicing you did at the sensor connector? Or if you used a vx harness a pic of the connector at the ecu adapter? It's a 5 wire sensor but the harness side has 7 wires. And the sensor connector has a specified resistor in it.

I believe you had pmmed me about the car previously. I'm gona check back on my inbox

Edit: sounds to me like the shop wants to make more money by converting everything over to a p28 equivelant and charging you for dyno and street tuning time. Don't get me wrong it can be done to achieve the same or even better mpg but it would be a heck of a lot easier and cheaper to diagnose the wiring problem.

BBrown7888 · 02-16-2014, 05:55 PM

Here is the pin layout website I used to wire the o2 sensor...

.:FFS TechNet : OBD1 ECU Pin out Schematics :.

Yes slownugly, I've talked to you previously. My o2 sensor has 5 wires and the harness it plugs into has 7.

slownugly · 02-16-2014, 07:33 PM

Ok, to answer your questions

1. Yes they can tune your car with a wideband that reads lean afrs. I have an innovate wideband and the gauge goes up to 21.9. The sensor might register higher. They can also eliminate egr and the 5 wire 02 but like I said you need a different ecu (which they can supply and install) You might have 400-700 dollars or more into it til your said and done.

2. Several guys have tuned custom Hondas this way without egr and achieve the same or better mileage than the p07. So egr is not needed. Does it help with mileage? A-b-a testing would prove that but you might be hard pressed to find someone who has done it.

3.since they are talking about a custom tune the wideband they are quoting you on is probably the aftermarket one used for tuning. Depending on the tuning route that might include welding in a second 02 bung for it.

It's a shame they don't want to diagnose the issue at hand. Of course they don't make as much money that way. I'd call a couple other shops that are fluent in Honda and see if they'd be willing to help you out. Too bad you are so far away I'd offer you to drop it at my shop.

turbothrush · 02-16-2014, 07:45 PM

2) If you are driving with economy in mind , the D15Z1 in the vx does not use any EGR at all. It only gives a short burst of EGR at high rpm when shifting gears and does not use it at all when in leanburn.