I have a 86 Z31 n/a 2+2 and I've been having some problems. The car is hard to start the first time of each day. After I start it the first time it will immediately crank up when I try to start it. The car sometimes won't accelerate and will bog down and it sounds like there is some backfire coming from the exhaust manifold but I'm no exactly sure that is where it is coming from. I just replaced the TPS and checked the MAF sensors. Not sure if they were even the problem. When I run codes I get 23, 24, and 31. One last thing, sometimes when I power brake the car it will start roasting off the right tire but other times it won't spin out at all, is that normal for this car? Any opinions or ideas will greatly appreciated because I am about to take it to a mechanic and waste ALOT of money :(

Codes seem normal to me. You could be getting abnormal input signals because of code 31 possibly from the AFM.

Tell me how exactly you checked the AFM with what pins and voltages you measured. Rev it past 3200 RPM's in second gear and tell me if you notice anything, if you don't notice a thing, it ain't the AFM. Read this carefully and listen to us or you may lose alot of money taking it to a mechanic.



Edited 2 time(s). Last edit was august 10, 02:11am.

Is the AFM the same thing as the MAF? I unplugged the MAF and my car wouldn't rev past 2,ooo rpm. I have an automatic transmission and I can redline it in 1st, 2nd, and Drive. My car is idling really crazy though. In park/neutral it is staying at 1200 rpm and when I put it into drive it drops down to 900. However, sometimes it will go down to the normal 650-750 rpm (in drive) but it will sound as if it is choking down and tries to lurch forward. One last specific detail is that the car has trouble accelerating to 20 m.p.h. from a dead stop but once it reaches 20 it will gain a burst of power. Any ideas on what that is about? Thank you in advance :)

intake leaks
misadjusted TPS

Thanks for the TPS advice. I checked the TPS and had a buddy who is really good with cars tune it right for me and the car runs a little better now. I checked for intake leaks but I couldn't really see anything. My car kinda makes a whistling noise when I floor it and it changes gear (almost like a turbo releasing pressure but not nearly as loud). Also, I checked the fuses and there are two missing. The first one is third up from the bottom on the left column. Every time I put a fuse in it the brakes lights permanently come on until I take it back out. The second fuse missing is the very top one on the right right column. Does anyone know of a good website with fuse schematics or does anyone already know what they are for? Thanks for the advice guys its really helping :)

the brake light one is your actual brake lights - it means the stopper rubber bumper is missing and needs to be replaced so you have brake lights again.

tune the TPS right for you? its a simple switch, its closed when the throttle is closed, and open when the throttle is off idle.. its not something you "tune".

the FSM has everything you need.

Are you sure because my brake lights work. I'm not quite sure what you mean by stopper rubber bumper but I will look over the FSM. Sorry but the definition of tune is as followed:[adjust for better functioning] So since you can move the TPS up or down to make it work better it is a type of "tuning". But thank you for your advice I greatly appreciate it :)

up or down? as I said, its a SWITCH, its either ON or OFF.

He's talking about how to adjust the TPS to make it switch "ON" or "OFF" at the appropriate throttle valve position. The FSM states that the idle contact should be closed at idle (700rpm) and remain closed until the throttle opens enough to raise the idle speed to 900rpm. Its not really "tuning", but it can require adjustment.

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1985 300ZX n/a

See my Z project