Porsche Forum - Porsche Enthusiast Forums

It has no spark at the moment..Sometimes it will have spark, and start, then after a few seconds it starts running rough and blowing black smoke until it stalls and wont restart..
At this point the plugs are black soot....
Then ill lose spark again...so far I tried a new coil, Ive tested the fuel pump and DME relay, jumped out the relay, put the DME and AFM from the 88 into the 83, cleaned and tested the grounds from the batt to the firewall and motor....I did notice that the tach dosnt move when theres no spark, (when cranking)could this indicate a faulty,improperly adjusted speed sensor??It hasnt been touched to my knowledge..Mabey its dirty??Im willing to put more effort into this car cause I really want to get it running...What im not willing to do is just start buying parts and spending $$ on parts that im not sure are going to fix it..
Any advice,help will be greatly appreciated..
Hulk