Thread: 1977 Datsun 280Z

jmercer gives good advise, however this is not a manifold absolute pressure sensing system, but an airflow meter system.
Similar to all old Bosh systems. Sortof similar to today's mass airflow systems, but with a big exception, it was mostly done mechanically with the airflow meter.
The air coming through the meter pushed on a spring-loaded door which levered to a rheostat and fed some info in conjunction with other sensors and the position of the meter was a big input as well.
Pretty archaic, yet masterpiece in it's day. A nightmare today! You can put 3 Webers on......Just saying!

Lot's of info to take in.... I doubt my wife will let me put Webers on it..... Yall have given me food for thought of some issues and some troubleshooting ideas.

Again thanks for all the helpful advice...yall rock!

HAR! A bit of advise, read the plugs. Rich or lean? Something with a particular cylinder?

The story may be right there!

I think sharptonn might have nailed it.

On spring loaded flap kind the variable resistor (potentiometer) on the side is the weak link. Some had adjustability. Sometimes a pencil eraser can cleanup the coil and contact.

Make a list of suspects and go through one at a time.

Gawd I haven't thought about this stuff in years. Your blowing cobwebs out. Har!!

I had the identical problem in a 1986 Isuzu Trooper. The fuel filter came off and it looked like mud came out of it. Put a new fuel filter on it and it was black soon enough in short order. When I would step on the gas it would bog and sputter like it was starving for fuel (it was), but when I would drive and "ease" into the gas pedal it would run right along. I realized the harder I accelerated the harder the fuel pump would draw fuel, which in turn was sucking up trash in my tank up to the pickup tube.

I dropped the tank and filled it with a handful of coarse sheetrock screws and a few large nuts/bolts. I hung it in a pecan tree in the yard about 2 feet off the ground and put about a half gallon of old gas I had lying around (wasn't going to use it in my mower) and just rocked it back and forth and shook it. This went on for a few hours. Dumping periodically and refilling the gas. The stuff that came out was gross. Black and brown rust and other crud. I did this until the bottom of the tank was bright metal then retrieved all my screws/nuts/bolts with a magnet and re installed and it ran great after that!

I had a 1972 VW type 3 squareback for 10 years until I got T-boned by a guy who ran a red light going the wrong way down a one way street.

Had Bosch fuel injection back then. The injectors leaked when it got below 40 Fahrenheit. Other than that it ran good. Good luck with your fixing the Z.

Fuel injector o rings were dry and brittle on my 88 cabriolet as well.
Best $7.00 investment in replacing them ever. Hardest part was sliding on the new ones.. A hollowed out sharpie marker solved that though and allowed me to roll the new ones onto the injectors with ease. Injector slipped inside the sharpie and the o ring rolled from the outside of the marker onto the injector, if that makes sense..
Certainly worth eliminating as a source of lean issues.

Maybe dumb suggestions, but maybe vacuum advance, PCV valve or a vacuum leak?
I had a '75 Toyota with at least 5' of small vacuum hoses running various places and if any one of those was open it gave those symptoms

We changed the spark plug wires and fuel filters. Gas looked good coming from the gas tank. Still runs rough and lots of black smoke and run rich still. We were tinkering around the the injectors and the power wires going to them are worn. Very loose and some aren't snapped tightly to the injector. I'm thinking of ordering some new wires for them. When we wiggled them at the injectors, the throttle changed some. I also toying with the idea of a new fuel pressure regulator too. A few parts at a times. We WILL have this baby on the road sometime during the summer or I'm going to be SUPER

If it is running rich you are getting more than enough fuel. Have you checked the air flow meter yet?