81 z80zx crank and start, but no run

[zeppelinboy]

So since this is my first post, quick intro.

 

This is my first zcar, just bought it sight unseen, arrived at my house on a flatbed, supposedly runs, but has bad clutch. Throw a new battery in it and it fires right up and runs for about 15 minutes, great, just need to replace the clutch and everything is all good! Great score for $350.

 

Anyhow, I just finished replacing the clutch and go to fire it up (still on jackstands) just to make sure everything is working alright.

 

The engine turns over fine and fires within less tahn a second, but after a few seconds of running it sputters to a stop like it is out of gas. I look down at the gas gauge and it is out of gas, so I run down to the station a pick up 2 gal of premium and slosh them in the tank. Crank, start, no run. let set 30 seconds repeat.

 

If I spray starting fluid it will run happily all day long on the ether fumes.

 

I hooked up a fuel pressure gauge (why is there no schader valve on the fuel rail, or am I just missing it?) between the filter and the fuel rail. I get 40 PSI before cranking and about 38 while running. The pressure never drops off before or after dying.

 

This is all of the troubleshooting I have done so far. Any thoughts on what could be going on?

 

 

Thanks!!

 

Justin

 

 

PS, I have a ton of other questions about these cars, but lets get it running first.

[Guest s130]

fuel injector clips the can fall off or get real nasty

did you mess with the fuel lines at all cause thats what i did

[zeppelinboy]

So, I replaced the fuel filter, no luck.

I then adjusted the idle speed adjusting screw and now I can get the engine to crank and idle now, but any time i even nudge the throttle, it will die. It will idle happily forever, but thats it. Funny thing is that the tachometer is not registering the engine speed. It did when I first had it running normally, so this may point to what is going on. I need to look at some wiring diagrams now.

 

So does anybody know what inputs the ecs uses for fueling and timing? Certainly, rpm has to be one. If the computer is not receiving a tach signal, will it display these symptoms? Anything else on the tach circuit that I need to look for as well?

 

 

Thanks!

[zeppelinboy]

Just in case anybody is following this thread, or for future posterity, the problem is now fixed.

It turns out that the AFM was the culprit. Pulled it apart, cleaned all of the contacts and everything works great now.

I guess the tachometer was just a coincidence. Now I just need to track that bad boy down.