I'm sure I'll be asking a ton of questions on various topics and posting random pics of my progress from time to time, so I think a single thread to host all of my blabbering is a good idea.

So I guess I'll link my previous adventures:

https://www.zdriver.com/forums/280zx-s130-forums-77/new-site-33809/
https://www.zdriver.com/forums/280zx-s130-forums-77/crankshaft-pulley-where-buy-33815/
https://www.zdriver.com/forums/280zx-s130-forums-77/new-injector-now-gas-mileage-terrible-34058/
https://www.zdriver.com/forums/280zx-s130-forums-77/can-i-get-crank-pulley-fit-34699/

Okay! With that out of the way we can move on to my latest project. Now that the car has a new crank pulley and has been timed correctly I see that it is still completely terrible on gas mileage. I think the issue may have been my dicking around with the adjustment screw on the AFM when I was trying to pass smog. Would anyone happen to know what the stock(ish) positions of the two screws should be? As in how deep should each screw be screwed in? I don't have a CO% probe or Air/Fuel Gauge so any reference would be awesome. Thanks.

 

Get an Wideband O2 - then you can adjust it properly and you can use it for future upgrades to a programable system or sell it.... otherwise you are just guessing....

 

Hi FricFrac. So if I get a wideband O2 sensor I would still need to buy an air/fuel gauge to read that data, correct?

 

^^^ Normally you would buy the sensor as a complete kit... then you can just plug it in to your lappy usb port. You can get wideband O2 sensor kits for around $200. Important for fine tuning... but checking everything in the FSM will get your car back to stock.

Make sure you check all the basics first. Read the spark plug tips, check and clean all sensors and connections. Make sure all vacuum lines are secure, tight, and not leaking, etc.

 

Well I'll have to wait on that wideband O2 :/ Getting my engine back to stock is definitely the direction I'm heading. I hadn't thought to check the spark plugs since they have so few miles on them but given how bad that pulley was its probably a good idea. Stock position of the AFM screws would still be helpful if anyone knows it . Also things like the temperature sensor - should I just clean the connectors or actually pull the sensor out and clean it?

 

So how reliable are the in car oil pressure gauges in these cars? When I'm driving its reading pressure but after I've driven for a bit and put the car in neutral the gauge reads no pressure :/ needle is all the way at the left end. Is this normal?

 

Not very reliable. Grab a new one (pressure sensor / switch on the block).

 

Thanks Nismo

 

So I frankensteined a "computer" together for my garage and decided to find a neat background. So I typed in "orange 280zx" into the google image search and my own car (pre-racing stripes) popped up as the first result! lol



Just thought Id share that since I thought it was neat :P

 

Okay dumb question... I don't have an o2 sensor do I? :/ I don't SEE one on the car and the FSM doesn't mention anything about it in the emission control section. I'm not just totally blind/retarded am I?

 

No O2 for you!!

 

Lol thanks evandubya!

 

Yup its a narrow band and it's in the FSM. Check the schematics and you'll see it there. It's also one of the very rare narrow bands (Ti instead of Zirconium or the other way around - can't remember off the top of my head) so running a wide band in narrow mode and sending the signal to the ECU won't work so you need keep the stock narrow band for the ECU.

 

I just checked the schematics and don't see an oxygen sensor. This is a '79 280zx we're talking about. Are you sure it was equipped that year??

 

'79 has no O2 sensor.

 

Sorry right the '79 doesn't have an O2 so stop looking for it and ignore my babling

 

lol thanks you guys :P So I guess in the future if I'd like to use a wideband o2 sensor setup for tuning that I'll need to pick up a header with an o2 port. New header.. "darn"

 

So the car was feeling like it was running a little rough, so I started pulling spark plug wires to find a miss. Well pulling #1 plug had very little affect and #6 plug had a huge affect. The plugs in between seem to have a bigger impact the closer I get to cylinder #6. So now I'm wondering am I looking at an issue with the Fuel Pressure Regulator here?

Edit: I also have cleaned all of the fuel injector connectors and all of the fuel injectors are remanufactured injectors that I installed a couple of months ago. Thanks.

 

Bump for great victory! Anyone seen something like this before? ^^^

 

Plugs, wires, cap and rotor would be a good starting point if you haven't done that already. Get the stock NGK spark plugs - they seem to be the best option for the L28.

I also highly recomend spending about $100 on a set of Magnecor spark plug wires - they are very very nice and after looking at some of the "good" wire sets these really seem to be the best.

If you find a header that doesn't have a boss for a wide band you can always have one welded on easily enough.

 

Well the rotor and distributor cap are new. I suppose new wires and plugs couldn't hurt even if they dont turn out to be the issue so I'll order those tonight. I'll have to wait to splurge on those super plug wires until I get through this list of "needs" for this car :/ I guess tonight I'll just go through some more basic diagnostics and hope I get lucky. Thanks FricFrac

 

Well I swapped around some of the plug wires to see if it really was the wires and my miss went away Maybe I loosened up some of the wires when I was turning the distributor to set the timing. Anyway new plugs and wires are definitely on the "need" list. Thanks again.

 

Can't remember if the '79 had a cylinder head temp sensor or not, but if those go bad, it will make the car run rich. If your Z has one, it'll be a small sensor located on the passenger side of the block near the 5th or 6th cylinder.

 

No CHTS for me thanks for the input though.

 

The notorious bad connection... I'd save up for the good wires if these ones will last you that long. No sense in buying something twice....