Hey all! This is my first post. I've been active in the Miata and BMW community for the last 20 years but am just diving into Zs

How I got here is a long story but I need some help with baselining my EFI settings. I have a wideband O2 sensor installed and am currently idling great at 13.5 AFR but I can't get the idle below 1100 RPM.  The idle speed screw is all the way in. The idle air screw on the AFM doesn't seem to do much. I did move my toothed wheel in the AFM to get where I am now (I marked the original position, though I'm not sure it was right to begin with)-- when I first got everything running it was EXTREMELY lean at 20 AFR.

My guess is I need to start with a predetermined number of turns out on the idle speed and idle air screws-- maybe half way through the full range of adjustment??? Then set the toothed wheel so I'm somewhere near 13.5 AFR and fine tune from there?

Any help would be appreciated!

I think that the ignition relay will swap in to your car, whatever it is.  You never said, I assume it is a 1975 - 1978 280Z.

It's behind the glove box in the ZX's.  It doesn't have the same part number because Nissan added a dedicated ground terminal.  But the relay inside and the connections are the same.  On the 280Z's the relay is in the drip zone by the fuse box and can get corroded.

Coil, other relays, alternator, AC compressor maybe.

Keep everything from the parts car! Parts are hard and expensive to find. Gut the interior, especially if its the same color as your car. Gut the HVAC, there is a resistor pack for blower speed that is mounted to the blower housing that is impossible to find if yours dies. You cant get the vacuum motors, that control where the air flows from the dash. Keep all the gauges. Keep the weather strip that is on the doors. It is NLA and no one makes the stuff yet. Pull it all and put it in totes. Keep the outside mirrors for when yours dont work anymore. Keep the steering column cover and all of the wiper/headlight/curze control/ blinker stuff that is in the column cover. Keep all of the control modules that are under the carpet. Keep the curze control actuator/cable that is in the engine bay. Keep the engine and all of the electronics. Keep the distributor. Pull the EFI wire harness and put it away. Keep the ECU. Keep the door glass. IF the windshield is good try and get it out and keep it (you cant get a new replacement). $^!# just keep the entire car if you can. There is so much that you cant get anymore!!!!

I would go back to a stock exhaust manifold and skip the header. The manifold off the spare car will be the same.

The O2 sensor that you installed will not help the performance of the car. The ECU is designed for a narrow band O2 sensor. The ECU wont know what do do with the signal from a wide band Sensor. The car will run without the O2 sensor connected. The O2 sensor has a very small part in the ECU calculation for fuel. Get a correct sensor 

The screws on the AFM that you adjusted are for air/Fuel ratio at idle only.

Places that are overlooked for vacuum leaks are dipstick, oil filler cap, Power brake booster, vacuum advance canister (if the diaphragm is bad) and the PCV system.

26 minutes ago, kickstand80 said:

The O2 sensor that you installed will not help the performance of the car. The ECU is designed for a narrow band O2 sensor. The ECU wont know what do do with the signal from a wide band Sensor. The car will run without the O2 sensor connected. The O2 sensor has a very small part in the ECU calculation for fuel. Get a correct sensor 

My car is a 77 Federal 280z so no oxygen sensor was on it at all. The wideband is just to help me troubleshoot. I'll plug the hole when I'm done.

28 minutes ago, kickstand80 said:

I would go back to a stock exhaust manifold and skip the header. The manifold off the spare car will be the same.

Did not realize this. The EGR port is definitely in a different place as the EGR tube is different. Seriously considering going to the stock manifold if I can't get this header to seal 100% with another shave of the stepped washers. 

Thanks for the detailed post! Everything I've seen prior is "drivetrain is the same, everything else is different" between a Z and ZX.  This helps me prioritize pulling parts.

The ZX manifold is different from the Z manifold.  It will fit the engine but I don't know if it will not conflict with something else on the way back.  Can't recall anyone using the ZX manifold in a Z or vice-versa.  Worth a test fit.

 

kickstand 80, he has a ZX parts car, and a Z driver.  Not a lot of crossover in parts.  The engine will swap though.  The ECU won't unless the wiring harness and AFM come along with it.

I was assuming that since your parts car was a ZX so was your driver. Yea you are going to have issues. I have a 77 engine in my garage (a own 3 ZX cars) and if you would like the exhaust manifold, pay for shipping and its yours.

I am in North Dakota.

Maybe we ca do some trading. Where are you located?

Edited August 2, 20231 yr by kickstand80

6 minutes ago, kickstand80 said:

Where are you located?

Portland, OR. I’m using the engine and drivetrain and a handful of parts Zed mentioned earlier in the post. Happy to trade. What do you need? Also, I’m not seven feet tall. I’m sitting on a bucket in this pic 😎

I will swap you the exhast manifold for the ECU and the EFI wire harness if the harness has not been cut. It can be removed in about 20 minutes. 99% of the wire is on the drivers side with one wire crossing over to the passenger side. That one wire follows the firewall and ends up near the battery.

Do you have the Downpipe as well?

I have part of it. I will post a picture of what I have when I get home. Working nights. It is all still on the engine.

Edited August 2, 20231 yr by kickstand80

One of the Y pipe bolts is broke off.

Par for the course. Very common problem 

I will have to soak the other 2 in Kroil or PB before attempting to remove them.