I have a tbi 305 motor in my 88 firebird and have touble getting the car to run. When I crank the car it cranks fine but it takes over three to four seconds to start to run. This is followed by stumbling (bouncing from 500-700rpm) and thick black smoke weather the engine is warm or cold. I have replaced the Tps, Iac, cleaned TB, installed msd 6AL, GM blaster coil, set timing (base at 4 degrees), new cap and rotor,checked injectors and nothing seems to help. What could my problem be? I belive I am getting enough spark and air just too much fuel. The car also has a open element air cleaner and a flowmaster exhaust and afpr which is set lower than stock. also if any one has pic of what a 88 TBI computer chip looks like post a pic and what are the two small electronic boxes near the computer one is black and one is yellow they both have AC on them. Thanks for the help.

 

Sounds like you need to back that base timing off a few degree's to fix the problem
SSC

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85 Camaro, 355/400 "drag car" in moth ***** 13.1@ 101mph on its last season run.
Plans: Possibly add N20 for next season.
82 Firebird, 305/350 currently moth balled.
Current plans: Rebuild 305 with flat tops instead of the dished "cups" for pistons or slightly built 327 with the 58cc heads from the LG4, Upgrade the 2:73 to 3:73 or 3:42 and replace the turbo 350 with 700r4.


"Web site under construction"

G0D Bless.

 

I put the base timing at zero and it runs the same just a little rougher on startup. When the car has run for about 5-10 sec smoke clears and engine is as smooth as can be. So why is it having such a problem at start up? With the timing based at 4 degrees I also use 89 octane gas.