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1j280z

1jz swapped 280z

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About 2 years ago I purchased my 280z for 300$. It was a rusted sad looking car that was stripped. I brought it home where I didn’t have a garage and just started stripping it. I got laid off that winter so I took it down to bare chassis. I took all of the suspension pieces and brought them to bare metal and painted them all. I put the car back come spring time then stripped the engine bay and interior following with a coat of paint. For a while I was gonna go with the 280zx turbo motor but then i changed. I ordered a 1JZ-GTE non VVTI and grabbed a trans from a Pontiac solstice. I taught myself how to weld when patching the sheet metal then took classes and actually got a job as a welder making decent money. I funded the z, grabbed a dash with gauges, interior pieces, wiring harness, front fenders and more. I welded up engine mounts and trans mounts, a driveshaft, and I even made brackets and mounted s13 calipers on the back! Now I wired the old to the new motor harness and I’ve had it running after welding in brackets and mounting my fuel cell. I can drive the car down the block but it runs rich as a pig and brakes up on any throttle. I’ve literally replaced about every single sensor on the motor and the ecu and igniter. Heck I hooked up an e manage ultimate to try and get it tuned out but nothing. I’m gonna try hooking up a fuel pressure regulator to see if that helps since I’m running a Bosch 044. I’ll keep posting for this build since I’ve since gotten a house with a big garage! I’m hoping to get it street ready by the time I’m 22! (April) thanks!!

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Here are some ideas I found in a quick Googling:

You weren't joking when you said it's running rich. Standard injectors?

Bad fpr?

What are you're A/F readings (I don't understand the A/F reading lean.........)

If you have a signal or ground problem with the sensor, the ECU is seeing lean, and that's why it's dumping more fuel.

 

Well, if both sensors are giving a lean signal, you have a problem that is most likely electrical.

And like I said, your ECU is seeing this signal, just like your meter is, and over compensating by dumping more fuel.

 

You need to find out why your getting a low voltage signal from your 02 sensors.

Bad ground, bad wiring, bad something.

There should be 2 grounds also.

Sensor ground, which should go to the ECU ground pin, 100.

and heater ground, that should go to the chassis ground point, like 22,23,94.

The heater lead should go to a switched 12VDC source, 69 looks correct.

And of course the sensor signal should go to what ever pin the ECU is looking for the low voltage A/F from (57).

Got it fixed. The iacv and vsv needed a 12 volt switched source. Runs perfect now. No more miss and pop. Thanks for all the advice guys. More than helpful as always

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I’ll trace my wiring! I bought an aftermarket 02 since that was my first try but recently went with a new oem one since the signals could be different. I have checked the ground pins for the ecu but not the 02 sensor yet. And I’m running about 10 afr it’s just how much fuel is coming out of the exhaust, if it just sees a lot of oxygen and not as much consumed fuel it will go higher in the 15’s and up. I want mine at least around 13 and it’s just not happening. I’ll give that a shot and may even add extra grounds. Thank you! 

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Look at the pids on your tuning software and check for voltages out of range, go from there. Does it always run in the 10s? Or only during cruising, idle, part throttle, wot, etc. If it starts off in the 10s on a cold start then it’s probably not your o2 sensor unless it’s wired incorrectly and is backfeeding the wrong circuit into the computer. Your ecm starts off in open loop during warm up and doesn’t pay attention to the o2 sensor until it goes into closed loop once the coolant temp reaches whatever the calibrated temp is (typically around 160*). 

Other factors for rich condition off the top of my head that aren’t Ecm related: mechanical timing, ignition timing, fuel quality, restricted exhaust, restricted intake system, wrong injectors, too much fuel pressure (but that’d have to be way off to run as rich as you are). 

Edited by zeeboost

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Ah okay I gotcha! When it first turns over it’s good for about 5 seconds then it drops to 10 haha. I’ve put a new belt on it since I had to do the water pump and it was my third time doing timing. I gotcha, hmm I welded up my own exhaust and there shouldn’t be any restriction it’s straight piped to a through muffler with 2.5 piping. I have the tuner off just to try and eliminate everything and get it to the basics. I’m about to go to the store and get some extra line to put my regulator in now. As far as I know the injectors are stock because I tried tuning it saying it has big injectors and It didn’t help too much. I was thinking maybe with the fuel pump and the 12v mod could maybe do it especially if my stock regulator is kinda bad 

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Btw if you haven’t checked it out yet, go to www.hybridz.org

 

That site is dedicated to z car engine swaps. There is a Toyota 6 cyl help section you could go digging through over there. You may find some help here but it’s more of a site for all original or lightly modified Zs. I like this site but I come here to get my purist fix on, see how inferior my Z is based on some letters and numbers stamped into the metal 50 years ago, how many speakers and modulations my radio caters to, along with all the other little hidden Easter eggs.

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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!

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1 hour 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!

I have you verified your fuel pressure at idle with a reliable gauge?

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3 hours ago, 1j280z said:

 I was gonna go with the 280zx turbo motor

a 1JZ-GTE non VVTI

wired the old to the new motor harness

replaced about every single sensor on the motor and the ecu and igniter.

e manage ultimate

hooking up a fuel pressure regulator to see if that helps since I’m running a Bosch 044.

2 hours ago, 1j280z said:

 aftermarket 02 since that was my first try but recently went with a new oem one since the signals could be different.

checked the ground pins for the ecu but not the 02 sensor

running about 10 afr 

 

I cobbled together your basic facts.  It's not really clear what you're using for engine management, the ECU and harness.  Also looks like you're just connecting things up then seeing what happens.  Not a great idea, especially with a turbo engine.  Most modern engine management systems have a fail-safe or limp mode to protect the engine when things aren't right.  Timing is retarded, and/or cylinders are shut off.

Also looks like you're not 100% on the O2 sensors and how they work, and the different types.  You need to get the right ones, guessing and getting lucky is iffy.

I'd get the pinout for your ECU and wiring harness and spend some time checking every circuit.  Adding extra grounds is kind of pointless.  There's no magic, just get the right parts connected the right way.

Good luck.  Looks like it will be a lot of fun when it's running.  Be careful too, you'll have enough to be spinning in circles before you know what happened.

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7 minutes ago, Patcon said:

I have you verified your fuel pressure at idle with a reliable gauge?

I second this also.  The 044 is a high volume pump.  Known for overpowering fuel lines.  The ECU/PCM works on an assumed base fuel pressure.  It can only adjust so much.

Edited by Zed Head
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Thanks for the replies everybody! And okay to sum it up.. it’s a stock ecu for the motor because I took out the e manage until it’s running correctly. I know about the 02’s I just didn’t realize the one I had purchased used voltage to measure instead of ohms. My afr gauge is not hooked up to anything just for readings to help me, although it did feed information to the e manage. I’ve checks some of the pins but I can’t really check continuity because my leads aren’t long enough to reach. I was replacing sensors based on the problems they could cause when they go bad since my cel doesn’t work. I’m in the process of hooking up and altering the fuel pressure now (if it’s too high) ! ?

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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

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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. 

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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 by Zed Head

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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. 

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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 ??

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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.

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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.

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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.

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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 

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