1989 civic DX d15z1/Hf tranny

[nitebluesky]

Hi,
I recently swap my d15z1 motor with an Hf tranny that i rebuilt two weeks ago. Every since the weather has gotten cold my car has been throwing a code 48 and my mpgs has dropped considerably. Now its at roughly 35ish. I converted my car to obd1. My 02 sensor 5 wire wideband is brand new. Ive been scratching my head on what causes it to through a code 48 LAF?

Please help.

[California98Civic]

Originally Posted by nitebluesky

Please help.

You posted this twice accidentally. I chose this one.

Need more info. Simply put, the code indicates a problem with the heated O2 sensor. Is it wired properly? Is there an open in any of the wiring? Did you test for continuity? Can you replace the current sensor with a known good one to see if the problem goes away?

I'm also just curious, how did you adapt the HF cable clutch for the hydro clutch d15z1 (VX) engine? Did you replace the gauge cluster too (the HF speedo is cable driven and the VX is the electrical signal kind of sensor). And I have been told on what seemed like pretty good professional authority that the HF and fourth gen Civics had a shorter countershaft than the 5th and 6th gen and therefore cannot be swapped... your case suggests maybe that's not true.

[nitebluesky]

I just now noticed that i did oops.

I had my buddy try to figure it out yesterday and mentioned the heater sensor in the 02. The sesnor is brand new and i dont get it. Tested from the ECU to the sensor. Iam hoping its wired properly because the guy that help me put the engine in could do honda swaps in his sleep. Does the ECU need to be chipped or chromed whatever its called? He tested for continuity for sure with his meter. It did throw a code 41 but that was fix. He was puzzled but could it be where it was located? header be the issue?

Its still a cable clutch. I replaced the cluster with an 89 civic lx cluster. Its still driven from the cable that originally came in the car. All in all it fit like a glove D series to D series. I am not sure if a d16/17 would fit on hf tranny. I put the tranny in in like an hour. I could email you a picture of it if you want. Its a 93 d15z1 motor with a 91 crx hf tranny. 4 gen motor leans forward a little causing the motor mount on the driveside become pinched. It doesnt shake or rattle.

[slownugly]

double check your grounds as well as the oxygen sensor wiring continuity.

[California98Civic]

+1 to slownugly's comment above: double check, even though you say it was already checked. Nice work with that transmission. Post up some picks, since you have them.

I'm a little confused too when you say you converted the car to OBD1 because weren't both the 93 engine and the 91 HF obd1 to start with? I guess I am wondering if you have the correct ECU for the d15z1 engine.

[cbaber]

The 89 car would have been OBD0. To run the D15Z1 you need the proper ECU which is the P07. Is this what you have installed?

The O2 sensor circuit is very simple. If you get an O2 code it's the sensor, the wiring, or the ECU. If you have the correct VX P07 ECU, I would next check the wiring. If you used the stock 89 harness you needed to add extra wires for the O2 sensor. Verify they are connected to the proper locations on the ECU by looking at an ECU pinout. If the wiring is correct, the ECU is correct, it's your O2 sensor. Being new doesn't mean it's 100% guaranteed to work. Which brand is it? Did you get the proper O2 sensor?

[nitebluesky]

I recheck and I couldnt find nothing. Its getting kinda of frustrating since with this swap I should be getting atleast 45 55 easily if ran right. My ECU is a p07-A00 and it is for a VX. I used a jumper harness that I bought from eBay that converts obd0-obd1. I did however used existing harness with the jumper. I dont have a picture for that. As for the sensor it reads on the box NGK NTK # 24300 L2H2 L1H1 5-wire Wideband Oxygen Sensor that i also bought from eBay. I wish I could borrow someones 02 sensor and see if thats the culprit, but you cant just buy and return stuff like that. Ill have to dive in again, but i might have to take it to a "Honda specialist" if i cant figure it out.

the 91 crx hf tranny is from an obd0 car. (rebuilt with bearing kit)
the engine d15z1 is a obd1.

On a side note : If you ever get an HF tranny replace the first 3 gears with a Dx gears because its gutless for sure. I should done that before i sold my DX. The HF now I can go 75mph in second gear redline at 6k. Super tall gears. At 77mph my car runs at 2300rpm top dead center for Honda gear ratio.

[nitebluesky]

I posted one picture of my car. Ill resize the rest later.

[California98Civic]

Nice looking car! Love the HX 14" wheels (maybe they're 13" VX wheels), the chin spoiler, and general apparent clean look.

I think you're saying you rechecked for continuity and it all seems fine. The harness could be an issue. Did the HF have lean burn? I don't think it did. So I wonder if the wiring connections are correct in the jumper harness.

[slownugly]

Yea I think the jumper harness itself would have to be modified as well. Not sure I never used one. But it's not throwing any other codes for the egr