1jz swapped 280z

[Zed Head]

Good luck.  

They all produce a voltage.

https://www.fixdapp.com/blog/oxygen-sensor

[Zed Head]

Consider buying an OBD reader.  It will tell you the codes that the computer is generating, which can come from feedback or just damaged components.

Some OBD readers can also scan live data.  With an app on your phone or a computer program and a USB cable, tou can see the senosr values, and how the computer is respnding.  IT's a great diagnostic tool and very educational.

I have the BAFX reader, and the Piston Android app.  Many other options though.  Not sure what year your engine harness is but it's probably OBD-II.

https://www.amazon.com/BAFX-Products-Bluetooth-Diagnostic-Scanner/dp/B005NLQAHS

[1j280z]

No they all have voltage go through them in a way, but the ecu can still read how many ohms it has in a way that could make it work... v=I/r lol I went to school to be an electrician and I’m a forklift mechanic by trade so I kinda know what I’m doing for the most part. I’m just 21 and self taught which isn’t too bad if you ask me lol. Also it’s a 91 I believe no obd2 for that. It’s just a jumper that you put in that flashes the codes but the light wouldn’t work. 

[Zed Head]

2 hours ago, 1j280z said:

No they all have voltage go through them in a way, but the ecu can still read how many ohms it has in a way that could make it work... v=I/r lol

Sorry.  Not right.  It's just not what the O2 sensor produces and not how they're used by the ECU.

 https://www.autozone.com/repairinfo/common/repairInfoMain.jsp?targetPage=productsHowToInspect&leftNavPage=productsHowTo&pageId= 0996b43f80a01215&subtitle=test

http://www.autodiagnosticsandpublishing.com/feature/o2-sensor-testing.html

91 is going to be the simple narrow band sensor.  And, 91, just like all of the EFI control systems, needs all of its sensors intact, connected and working correctly.  I doubt that it has a limp or fail-safe mode.  The engine is just running poorly because the inputs to the system are bad, including ignition timing and fuel pressure probably/maybe.  At least it runs though.

Good luck. 

Edited December 2, 2018 by Zed Head

[zeeboost]

8 hours ago, 1j280z said:

I gotcha and your car is beautiful if it’s your profile pic! I’ll give that a shot thanks! Haha that’s funny! I might of went pretty stock if I had a better starting point haha. I like making the car how you choose!

It was a car I built roughly 10 years ago and is one I should've never sold. Guess I've just kept that avatar there in remembrance. I started off doing engine swaps in these cars, as they were cheap enough to buy as a project shell and modify the blank canvas however I want. But as of recent the prices on some of these just make me feel too guilty modifying anything, and have somewhat caught the purist bug with it. Kind of interesting when I walk from one garage with an lq4 f1r pro charged widebody s30 to the garage on the other side of my backyard with all original '70 that I keep trying to source out as many OE parts as I can. 

 

4 hours ago, 1j280z said:

No they all have voltage go through them in a way, but the ecu can still read how many ohms it has in a way that could make it work... 

ECUs actually read voltage, not resistance. Resistance of the sensor alters the return voltage to the computer. Sometimes amperage readings are also used as signals, but most of the time its voltage. 

[1j280z]

That’s just what I’ve heard and went by since I’ve seen the different types. I gotcha though. Okay I’ll try figuring out what the sensors should be outputting and track them down one by one. The wiring isn’t the best since a little was cut when I got it and I fixed the majority. Also fuel pressure regulator is in and did not help it’s sitting at about 38psi now after adjusting it. And yeah but say the ecu sends out 5v and so many amps, some 02 sensors just use resistors that change in ohms when the fuel amount changes. So yes the ecu does read the volts coming back. If it starts at 5k ohms and changes to 10k it’s gonna send back half the voltage since the amoerage would likely stay the same. And that’s awesome! I agree on that if I had a clean car to start I’d make it like that!! For now it’s my little Frankenstein ??

[Zed Head]

24 minutes ago, 1j280z said:

fuel pressure regulator is in and did not help it’s sitting at about 38psi now after adjusting it.

And yeah but say the ecu sends out 5v and so many amps, some 02 sensors just use resistors that change in ohms when the fuel amount changes.

What was the pressure before?  And what is it supposed to be for your engine management system?

Sorry, again, but there's no "yeah buts" that work.  We've all made mistake in how we thought things worked.  Best to absorb the new knowledge and move on.  You can waste a lot of time trying to make wrong look right.  Your statement has a lot of new wrong in it too.  Seriously, it does.

 

You might take a step back and ask yourself if the 1991 engine management system you're using is the most effective way to get what you want out of the engine.  What you really need is the factory service manual for a car that used that engine.  Looks like the Toyota Supra used it.  https://en.wikipedia.org/wiki/Toyota_Supra#A70

https://www.amazon.com/Service-service-electrical-diagrams-specifications/dp/B005DGOLW4

Might be more effective to just use Megasquirt.

[1j280z]

it shot up to 9kg/cm which is about 120 psi lmao. But there’s no way to change the output voltage unless something is using it so in form resistors haha. But I’ll just go by that so we can stop this. I’ll take your word on it reading the voltage. Yes I was thinking about going mega squirt and just saving the e manage for a different car or my Audi haha. I’ve gotten wiring pin outs and what not but just haven’t been able to check for continuity or what the sensors should be putting out in order for the car to run correctly. Everything seems to be good for the first 5 seconds, then it runs rich in the 10’s and after its partially warmed it cuts when revving. I’ll try searching for the manual, thank you.

[zeeboost]

Since you repaired a harness that was cut, you should probably start by unplugging every connector from the ecm and sensors, backprobing the pins and verify with schematics that every wire goes exactly where it’s supposed to and only there. May be a little overkill but with every wire you can also measure continuity to ground just to make sure there wasn’t anything shorted / pinched during installation. Or maybe some welding slag didn’t burn through the harness and bridge some wires that shouldn’t be touching. 

 

Cant tell you off the top of my head about older Toyota engine management, but with older nissans, rpm limiting was synonymous with maf faults (I also come from the land of z32tt so that’s just the first thing that pops up)

 

you should wire in a bulb that the ecm can use as a temporary check engine light, put ecm in self test mode and see what codes you get. Or the tuning software you’re using...is it unable to retrieve trouble codes? That would be better than shooting in the dark.

[1j280z]

I’ll try and get out of work early tomorrow so I can give that a shot! Yeah I was debating on buying a whole new wiring harness for it. I’ll source a light for the cel soon!! I did notice when I hooked up my emanage that it said there was an error on cylinder 2 and 4 sometimes 6. It’s differently wired on the car since the order that it fires is different but I did triple check the wiring for it and it was all correct to the ecu