Seattle_Max

Ok so new info on my Z, 1984 AE Turbo, 130K
It cut out while driving, couldn't get it to start, jumped it and everything, so i brought it home.
It's getting fuel, but I don't think its getting spark. My friend/local mechanic said it has an oil leak which may have dripped on some wires and screwed em up.
It's giving me the following codes:
23: Throttle valve switch (Idle switch) circuit
24: Neutral/Park switch (VG30ET only) which it is
31: load signal circuit

I have no idea what to do, but i think it may be the wiring.
Anyone have any similar problems?
Need help asap haha
thanks

zxguy1986

You downloaded the FSManual from XenonZ31 Reference, right? Your FSM from pages EC 31-EC 42 gives instructions for the ECCS diagnostic procedure (which you had to read) and then gives a specific inspection procedure for each code that comes up. Have you checked all the items indicated?

If your mechanic buddy can help you with that, show the applicable manual pages to him. I think a guess like 'oil dripped on the wires' isn't much help to you. You are on the way to a solution if you check out the code procedures in your FSM. If all of that doesn't do it, come back here with accurate symptoms and we can work on it with you.

Spencer

I believe in the FSM it says that those 3 codes are supposed to be there for the Z31. Pretty darn sure.

PredatorZ

I have lived in Seattle before, so I know it rains a lot there. The issues you are describing can be caused by water in your TPS, the way it sits water can get in the connector and short it out, and when it dries, leave corrosion behind. All the connectors to the fuel injection, MAP, TPS, cold start circuit, and a few other connectors which all resemble fuel injection connectors (except map) can get corroded with time. Also ground is very important, the stock ground can be compromised, and is carried through the frame and body panels, which are not the greatest conductors compared to copper, over time this body ground deteriorates. To fix this issue a star grounding system can be implemented. All you need to do it make a common point and tie all your major areas together. Run a ground from your Negative terminal on your battery to the ECU and then to the intake manifold/ plenum (cluster of sensors there, which all need a good ground), this will eliminate ground loops and open grounds and give your computer a solid ground plane. After a star ground system, you can replace all your connectors with a kit from fricfrac, was like 55$ and well worth it, he spent a lot of effort sourcing exactly what we need, and he is an Electrical Engineer who knows his beans, he is highly respected in the ZCar community. I did a short write up on my connector conversion, was pretty simple procedure.

https://www.zdriver.com/forums/280zx...y-39110/page2/

Can't guarantee this will cure your problem,but it is something these old cars can greatly benefit from, for what ever reason, these cars have a reputation for having electrical issues, and a good ground and sound, solid connections are the very minimum required to get things working.

Seattle_Max

Thanks for the help guys. I'm pretty sure now that it is something to do with the wiring/wiring harness, as here is no park from the distributor to the plugs. Gas is getting there, but it isn't sparking. The engine bay is really cut up du to PO removing AC and screwing around, as well as PPO leaving t in an open field for 3 years with no cover. Guess I'm just going to have to find th broke wire or connector that is causing the no spark, as the codes don't help at all. Battery is good, have tried charging it to no avail.
Also going t check the grounding, thanks predator Z.
Basically, the darn thing just died on me as it was rolling towards a stop sign, and has refused to start, have also tried swapping the distributor, which didnt help. Sriously considering gtting a new wire harness, this one is crap.

rogerz

how do you know you have fuel? did you check the pressure on the ring? did you read the fsm? TPS is not your problem. grounds can well be your problem the negative cable must go first to a bolt in the frame and then to the starter. grounding thru starter is not reliable. how do you know you have no spark? If you do have no spark then the ignitor (power transistor may be bad) the only reason z31 get a bad name for electrical issues is that no one bothers to examine and maintain the battery and battery cables. you don't need to do that star thing that predator is touting. it is a welded body. that got started back in the days of Lucas the prince of darkness when bodies were bolted together. true steel is not the conductor that copper is BUT when you have an infinite number of paths resistance overall diminishes to zero. examine what happens to resistance when you have a number of resistors in parallel. I have an MSEE so I know a little of what I speak. however local grounds do need to be free of corrosion to have good contact. Come to our meeting at Issaquah XXX drivein on April 9. starts at 7pm but we generally get there a tad early. meet some z guys and get some advice ZCCW.org the website is a little messed up now but go to the quick link to activities. get your battery load tested. marginal battery will drive you wild.

Seattle_Max

I'll try to come through, just hope my Z will be fixed by then. Going to get a new wiring harness and just get my mechanic on it because I cant get it to work.