infamous stalling problem

[50thturbo]

Greeting,

My '84 z31 50th anniversary turbo bought it for $580 with a bad $15 clutch slave cylinder and have 77k mi. it started with sudden shut off on freeway a few times a few years ago. It would restart instantly by itself. Since the car was parked for 2 years now it wouldn't stay running with difficult starting. It will start for a few seconds then just died. It will crank until the drained the battery and can start a few times for a second.

Codes i pulled: Idle control valve, Air con
Parts replaced: ignition module, fuel pump relay

When unplug the AFM, it doesn't fire up at all, reconnect and it fired up for a second. Fuel pump pressure at ~36 psi, confimed with a pressure gauge.

I have eliminated fuel/ignition since the fuel pressure is good and it does fired up. But something is causing to just cut off. I search all over the net, it seems very common and no one have the same fix. It's either fusible link, CHTS, ignition switch, loose wire, AFM, distributor, pickup module, ECU, leaking injectors.

I'm pretty much stump at this point. Feel free to point out the problem. Thanks

[evildky]

Depends on your set of issues. The CHTS gets thrown around a lot and is a common issue but it is only a problem on warm starts, as a failed chts causes the ecu to think it's cold and sumps more fuel sometimes to the point of fuel fouling the plugs.

Your issue seemingly intermittent I'd suspect the ignitor which you've already replaced or the cas, which is part of the distributor, sometimes they get warm and fail intermittently and seemingly without reason or rhyme but they do tend to progressively get worse making diagnosis easier.

[50thturbo]

something is causing either the fuel pump not to send fuel after it started or kill the sparks. it will prime every time. Sometime it takes a few cranks to start, most times 20 cranks, but always died right away even give it gas. I have google for a week only found 2 fixes with AFM and blown plenum gasket. Anyone have input?

[evildky]

Well then I guess your issue isn't intermittent. So you could have a bad, CAS, ECU, ignition switch, wiring or one of a few different relays. This is a rather odd issue, Which I why I'd suspect the cas or ecu. The upside is if the problem is so persistent testing is a lot easier, you need to figure out if you are loosing fuel or spark or both.