Starting problem and possible carbon buildup problem

[Project_Black]

Hey guys, I'm trying to get my 78 Z running. I bought it from a guy who let it sit for a few years. He told me it ran when he parked and he had just recently tuned it up. Or so he says. Wires and distributor cap looked ok. Oil was fine. Spark plugs had black soot on ALL of them and the car would barely turn over. So fast forward a few weeks later and I have replaced fuel pump, FPR, plugs and rotor button today(looked like crap) Distributor seemed to be fine. Now the car turns over just fine but wont start. Just keeps turning and turning. I havent had a chance to get someone to turn it over while i check the spark so that is on my list for tomorrow. But after i checked one of the new plugs today, There was a little carbon on one of it and it smelled like gas. It is getting good gas through the fuel system now btw. SO here is my questions: 1. What would cause carbon to get on my plugs after turning it over a few times. 2. My MAF sensor is completely black inside. will that cause it not to crank and can i clean it up and make it good again with maf cleaner(not sure if its bad but looks like hell inside.) 3. If spark is good and maf is good, what the hell is going on?? I really want to get it on the road and before i worry with anything else i want it running. Sorry so long and thanks for any help.

[Willoughby Z]

280 uses an Air Flow Meter (AFM). Cleaning it would definitely be in order. There are checks that be done with a multimeter (EFI "bible" or FSM).

Use the multi-meter to verify correct resistance operation of the two sensors mounted underneath the thermostat housing. Use the manuals to verify proper operation of the fuel pump. Check vacuum readings. Cold start valve, injectors. Bad information to the ECU would will cause so many issues that it will drive you crazy. Clean every electrical connection/ground you can find and protect them with DeOxit (or equivalent).

Good sensors+ good connections+good signals= good beginning for finding the real source of your problems.

[Project_Black]

Got it running finally. But it wont rev with the Air Flow meter hooked up. But im going to clean it tomorrow and see if that helps. Also, will the AFM from the turbo hook up to it? I checked local auto stores for a new one and they are like $400 but there is a parted out turbo one at a local Junkyard and i could get it cheap.

[FastWoman]

PB, I "think" the ECU dumps lots of fuel when the AFM is unplugged. On the other hand, I *know* this happens when the coolant temp sensor is unplugged. What happens if you plug back in your AFM, unplug your coolant temp sensor, and then give it a crank? Alternatively, what happens if you leave both plugged in and disconnect the vacuum line from the fuel pressure regulator. These will both run the engine richer.

If you can get the engine to run by doing any of this, I'd say your engine is fuel starved. The reason "why" might be a bit more difficult to determine.

FAIW, the carbon/soot in the AFM won't affect running, but it's probably a reflection of a history of backfiring from lean running.

Oh, and don't use the turbo AFM. Your ECU isn't calibrated to use the signal from anything but an N/A AFM.

[Project_Black]

Thanks guys. Ill keep you updated. And BTW I like it here better that zcar.com. You guys are much more helpful and nice to noobs like me.:classic:

[cozye]

It's nicer over here. You are on the right track.