Sorry for the lenghty post and misspellings, but I figure the more information I can give the better someone can help me.
,
2002 Chevy Blazer
72,000 miles
4.3 L. Vortec V6
Won't start, turns over but sounds like it is misfiring, (comes to a lurching halt randomly when turing over) OBDII diagnostic code "random misfire in all cylinders"
This happened over night, ran perfect one day, nogo the next.
I have replaced recently,
Cap-Rotor
Ignition Module
Coil
Crank Shaft Position Sensor
Spark Plugs & Wires
I did all this about a month ago, all to absolutely no progress
My wife towed it to a shop & had it diagnosed,(she thought it would be a quick, cheap, fix lol) (I was fishing.... go figure)
They came back with "Spider Injectors & Assembly" (and a estimate of about $2,200) She had it towed back home.
I bought a fuel pressure tester & it was slowly loosing fuel pressure after the key was turned off. (I assumed it was leaking out of the spider assembly somewhere) Also it turns over & sounds correct (no misfire) if you disconnect the spider injector sender unit on top of the intake.
I bought an entire running engine out of a totaled vehicle (everything matches up great & I checked casting numbers to make sure it would be interchangeable)
Last week I took the intakes off & swapped the spider injector sender unit & all of the spider injectors, got it all put back together and I still have the same problem. However it holds fuel pressure after the key is off, (jumps to about 60psi w/ key on, but stays at 50psi overnight w/ key off.) so I guess they were leaking but not the cause of my problem
Today I pulled all of the plugs out, replaced them, disconnected the fuel pump & cleaned out the cylinders from all of the previous cranking, & I was checking spark before I put the plugs back in, I noticed that the #1 cylinder would fire twice on some strokes & only once on other strokes with absolutly no pattern (that I could discern) I checked #4 & it appeared to be fireing correct (once per stroke) I then checked #6 it would fire similar to #1 (twice sometimes) I thought this was wierd so I swapped the coil & ignition module w/ the ones from my other engine (again) & had the same result, I figured it was some wierd vortec stuff I proceeded with putting it back together. With no fuel connected I tried to spray carb cleaner in the intake while turing it over it still would not start, sounded like it wanted to a few times, tried it with the air cleaner (mass air flow etc..) hooked up & with out, same result.
Like I said I have an entire engine sitting in my garage, but I don't know what direction to go,
I am pulling my hair out over this one, can anybody give me some advice.
Thank You for your time,
Cody Samford
