hey z lovers;iam new to this "Z" club thing,even though i have owned a number of Z's over the years.Ime also computer stupid,so i feel like Ive taken quite the step today!the reason Ime doing this is I have a 77 280z that is having a problem that I thought i might be able to get some input on.It starts and idles fine....for about 10 seconds.Then the motor drops in RPM,begins missing,and starts blowing black smoke out exhaust.{obviously too much fuel}This does not happen gradually,but suddenly,like a switch or relay opens.any ideas?

Edited February 8, 201213 yr by crazy428z
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Look for blues tech tips cleaning electrical connections. start there.

Then vacuum leaks.

A good battery is a must.

Get free FSM download.

The air flow meter needle could be stuck in the wide open position. I had that problem before. Take the cover off and give it a look. Also you might look at the TPS right below the AFM, small black cover that can be poped off, that needle arm could be sticking too.

Edited February 8, 201213 yr by siteunseen

thanks for the reply,and the advice.Battery is new.Ive cleaned every electrical connection in my Z with elec. cleaning solv.,and a toothbrush.{thank god for lots of spare time,and having a warm garage while living jn the rainy northwest}Ive reringed and put new bearings in this motor 2300 miles ago,and did a vac. leak check,and retorque at 2000 miles.It was running great until mon.I drve home, parked it.When I went to go start it 30 mins. later, Ibegan having this problem.Z"s are a learning experience at times.

I just put a new AFM on it yesterday,because one of the fuel injection circuit tests related to the AFM wasnt quite right,so I replaced it with a rebuilt unit that now tests out right.I will check out info.on TPS though.I did replace it with a new one last year,but as we all know........ "stick" happens,right? Thanx.

I posted this in your other "new" thread. Some details on the "fuel injection circuit test related to the AFM" might help you out. What was wrong? Good luck.

From other thread -

"Download the FSM. Run through the tests in the Engine Fuel section. You'll need an ohm-meter and a fuel pressure gauge. Without measurements it's just gambling. Measurements at the ECU connector are best.

More history on the car and engine would be good also. Did the engine run fine for ten years and start doing this or did you just buy the car and it's done this since you got it? "

Thanks for advice.I checked them both and they seem to be in good mech. condition and seem to be moving fine.