Hey guys,

New to the blazer world, but not mechanics. just for some background on myself, I am a school bus mechanic foreman, been wrenching on deisel and gas engines for about 6 years now pro. worked for a chevy dealer, and a ford dealer before i started working for the state as a school district mechanic. so here's my problem:

my buddy has a 2000 blazer with the 4.3 and the spider injectors. he had a leaking lower intake gasket, and i had never done one before so i figured i'd take on the challenge. pulled the motor apart, replaced the gaskets and got it back together. initially, i had timed it wrong (thats what i get for not using a compression gauge the first time, and relying on a buddy to help me), but i didnt realize at first it was timed wrong. so i was cranking it all together for probably a good 5 minutes (over the course of trying to figure out what was wrong). well the next day i pulled the distributor, timed it according to the chiltons manual, and fired it up...only problem is it ran like crap. sputtering and misfiring and just plain running rough. so i shut it off because it wreaked of fuel, and had a check engine light on. so i left it until today to check the codes, i got a p0135 for the b1s1 o2 sensor. went underneathe, didnt see any corrosion or burned wires. so i reset the code, and it did not return. i restarted the vehicle, and it had a stft b1 of 50%. so i shut the truck off immediately, as i did not want it pouring fuel down the exhaust pipes. here's a few things about it just to add on to my book i've got going:

cap and rotor were replaced with intake change, wires were replaced 6 months ago (duracrap. the cap and rotor were bad, so i may have to replace the wires too) plenum gasket was changed with lower intakes. ive sprayed the area down with 2+2 to check for vacuum leaks, could not find any.also used propane as well to check. intake gaskets were torqued in sequence, but not with a good torque wrench (good one is at shop) so i may bring that home and retorque the intakes. not sure where else to look, may try to reset timing yet again, couldve sworn i had it right this time though. any other ideas what may cause this?

 

This may sound stupid, but put the old cap and rotor back on and try it. i had a NEW rotor arc straight through the plastic to the dist shaft. Its a cheap try. if it smells like its dumping fuelit bet its just a miss and not a vacuum leak. I bought a blazer that wouldnt run, smelled like a gas can and had the muffler blown up. Shop said it needed a spider assembly. It needed a cap and rotor. Runs great now. Good luck!

 

are you absolutely s 100% sure it's timed right...just a thought. Jerry

 

You talk about fuel leaking if you did not replace the orings on fuel line by distributor they are most likely leaking fuel and they come in the intake gasket kit, could also affect fuel pressure and make misfire codes not to mention start the truck on fire

 

i replaced the o-rings on the bracket for the fuel lines. turns out it wasnt timed right, and once i retimed it (by myself with a compression gauge instead of relying on others to help) it fired right up, but with a miss. replaced the plug wires, runs much better minus a dead miss on cyl 5. used my scan tool to do an injector cut out, and 5 is the only one that doesnt make adifference in rpm. swapped plugs, between cylinderst o see if it followed, and the miss stayed on 5. looks like an injector 5 failure. now my question is, how do i tell if the spyder is shot, or if i can get away with just replacing the injector?