OK guys. I'm really needing some help here.. I been turning wrenches most my life but this has me mind blown.. my 4.3 will not start.. bought the truck from a friend of mine. Every sensor has been replaced, new pcm, spiders been replaced, pull pump, coil , plugs wires,cap, rotor, everything..have good compression, and fuel pressure, it'll stumble to start on first turn but completely dead after.. it's throwing me off with a yellow spark at the plug. Blue at the coil and distributor.. and I have a real bad raw fuel smell after turning it over like its flooding itself out. I put it tdc and timing is right on.. .. I'm stumped .. anyone out there having the same issues?

 

leaking spider under plenum pull off throttle body and look for shinyness under plenum. should be carbon black not shiny

 

Not the spider injectors.. already went over that in the message . It seems like that the route of everyone's answers. In this case .. not the problem. It's not fuel... narrowed it down to vacuum and possible intake leak. Got it running strong.. perfect idle. But won't go over 2000 rpms keep throwing maf code.. after its been replaced.. therefore.. anyone? Anyone? Air coming in after the sensor,... gotta chase it down now.

 

Maybe the MAF sensor is defective or one of the wires to or from the sensor is damaged.

 

Begin by telling us exactly what we are working on. Year/Make/Model/Driveline. Then tell me if you now have a scanner capable of reading live data (Extended GM PIDS). If not I will recommend an inexpensive scanner setup that uses your cell phone, but will need to know year first and what phone you have (Android or iPhone). Then we can get started. If your vehicle is 1995 or older, I won't be able to help you.

 

Is it possible that the dizzy was reinstalled slightly off after doing the spider assembly?