tuning a 2m4

[ke4mns]

hi i just bought a 87 fiero with 2.5 and when i pulled the plugs there where black,this car has electronic distrubtor,it also pops back throught the throttle body when you start it cold how can i fix this thanks

[Jack_ink]

well it sounds like you may have a vaccuum line leak somewhere also for the distributor you can replace all the little mechanisms inside it and also check your air filter if you havent already... then look into your timing and see if theres a spit upon killing the engine or if its slow to start (advanced/retarded timing) i am not sure about your mechanical capabilities and/or location but I have another 2m4 motor that has very very low miles on it am thinking about selling... after my car wreck building a dunebuggy just seems too hard. and if it only spits up on starting but the timing and such are ok it could be your cold start injection system... or just has a valve problem...

sorry to be vague but I dont usually deal with US 4cyl's they tend to be wierd to me if not in a V

[racer199]

try a new set of spark plugs and wires ac delco works best on my 86 check for vaccum leaks black plug readings indicates a too rich fuel mixture

Charlie