i got this 1980 280zx a few weeks ago it had been sitting up four years so the first thing i did was drained the fuel tank and cleaned out the fuel lines and the fuel pump and checked the fire it was firing good but was orange instead of blue but i went ahead and tried to crank it and it fired right up but it seemed to be flooding very bad blowing black smoke very rough idle so i checked fuel pressure regulator and had to replace it then it ran a little better but was still flooding black smoke rough idle the whole nine yards so i noticed when i pull a big vacuum line off it revs right up and black smoke goes away i am at my wits end with this car i'm thinking maybe the temp switch but i don't if this car runs off a closed loop till it warms up cause it does it hot or cold so i am asking the masses of Z-car fans for help before i spend any more money running down this problem i think it is a simple problem but i have never ever seen or worked on a car this old with fuel injection so i truly don't know the ins and outs of this prehistoric computer system any help would be greatly appreciated thanks a lot

 

the AFM might need to be replaced. Find a old one from a junk yard. also the cold start might be malfuntioning and spraying all the time. pull the plug from it as well. after you have tried both of these. get back to us so we can help narrow it down.

 

i didn't mention this cause my post was getting long on me but before the car sat up the previous owner had problems getting it to start and he changer the AFM and the injectors i have the old AFM and have tried it but i don't know how to check either one to see if they are good or not and i have unplugged the cold start injector

 

long post are ok. there good due to more info involved. Does this happen in just low rpms or both low and high?

 

what vacuum line is this specifically?

 

i have found the problem it makes perfect since now the cylinder head temp sensor was unplugged and it was seriously over loading the fuel injection but i plugged it in and presto started running perfect now i have this car running great and only have about $600 in it i am very happy about that and i also found a great forum to read and participate in thanks for the willingness to help and i will be glad to help anyone of you in any way i can in the future PEACE

 

oh hey... don't forget to check the CHTS!

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