Hello everyone my apologies for this long post but feel it may help you guys help me figure this out. I have a 2002 blazer 4.3 vorec I was driving and all of the sudden died out 3 months ago and cranks but will not start.

I have looked here in the forum and tried everything with no luck yet.let me give a bit if info on what I've done and found so far.

first thing I did was check for spark,fuel and air. It had it all.

*spark plugs... I found the spark plugs where completly black so I got new ones since it has been a year since I last replaced them.still no start.

*distributor cap and rotor.. I found it really bad so replaced them and still no start... I noticed the distributor had a lot of play so I took it out found the gear really worn and grinded so I replaced it.( yes I did top dead center,positioned it on the 6 as it sat flush on the motor.....still no start lol I thought for sure this would be it..



*replaced spark plug wires just in case I measures their resistance and they where a bit off.....no start


*checked the crank shaft sensor looked just a bit dirty got a new one but haven't put it on becuse I would have to do a relearn and dont have the means.


*fuel....I checked my fuel pressure and its 55-60psi and holds after cranking it for more than 10 min. So the pressure regulator should be ok. I wanted to see if my spider was ok so I removed the plenum and reconnected the spider.after removing power to the coil for safety.I exposed the injectors one at a time while I cranked and found gas spraying normaly in all.I also did not see any gas leaks anywhere in the spider unit or fuel pressure regulator I put it all back together....no start


*fuel..... I thought may its bad fuel or water in it. So I removed the fuel filter and turned the fuel pump on and drained out all the fuel. A little dirt a came out but no signs of water contaminants ..so I Added fresh new fuel ...no start


* I was starting to give up and I know I haven't checked for engine pressure test but so I started to think its a blown engine or something really bad like the valves or major engine problem but it cranks over with no rattling sounds and feels like it has pressure.


So I thought ok maybe with all this testing I'm flooding the engine with gas and not starting. I do get a NASTY kick back (feels like the engine while cracking clockwise goes backwards counter clockwise just a bit)and blows out the intake when cracking and had to replace 2 starters as the kick back damaged them 😩😩😩. Also had to get a new battery and get a charger because all this testing killed my already dying battery 🤮🤮🤮😭😭😭😢😢😢 so I removed the fuel relay to see if it cranks differently and lord be hold ... after a few cranks it stopped kick back and blow out (from intake) and started to crank normal so while fuel relay was off I sprayed starting fluid and it turned on 😀😀😀🙌🏽🙌🏽🙌🏽🙌🏽 and quickly put the fuel pump relay back on and it stayed on 😀😀....but started to run ruff with missfires and after turning off it wont turn back on. Lol


*so what I'm noticing is when ever I remove the fuel relay it slowly acts better and want to turn on but as soon as i put the relay back its starts all this blow back and kick back. I feel like this was the original problem and all other stuff I did was needed anyways but this is the original problem. I not a mechanic just have a bit of knowledge from wrenching and still lost as to what this could be. I feel like something is not functioning correctly with the fuel return and its just flooding the engine or map sensor but I have tryied several times and checked for codes and get nothing 0 codes !!! After all the parts I've replaced I think I should be getting a bunch of codes!! (I tested my obd2 with my other cars and it works fine) so I'm also wondering if I have a bad pcm ecm computer.

 

It almost sounds like your Timing is off. I had my distributor off by like 2 teeth and it acted the same way. Reset it and it was good to go. That is the only thing that comes to mind.

 

Thank you for your reply I checked it 3 times made sure I had tdc I used a ballon on a hose connected to the #1 sparkplug hole and as the balloon inflated i new the piston was coming up turned clock wise till I hit the 2 markings at that point I used a screw driver to prep the oil peg and prepped the distributor so that as I inserted it,it turned about 25 degrees until it sat flush ending with the marking at 6..


if its the timing why does it choke and start to run only when I remove the fuel pump relay? I check the timing again. Is it possible the timing chain jumped a tooth? I checked the timing chain by looking at the distributor and turning the pulley slowly both directions and it looks like it moves with no play on the chain

 

I had a similar issue and it was the crankshaft position sensor. Luckily for me i knew someone with a scan tool.

 

I have the crank shaft sensor but not scan tool so I havent replaced it. Do they rent these at the auto parts?

 

From what I have read you need to do a "relearn" on the new sensor.

 

I did not see any reference to checking for spark. Do you have 1" of strong blue spark at the plug end of your ignition wires?

If not, then at the coil output?

George

 

Also, when you say kick back do you mean a back fire or the starter stops cranking suddenly with no ignition backfire? When this happens do you smell gas and are the spark plugs wet? If they are wet is it water or gas? Is there water in your oil?

George

 

yes Thats what I've read I'm gonna see If I can rent the scan tool but never done it before so need to research a bit which one is it and how to do it.

 

I did check for spark started at the sparkplug by using a spark plug tester the one that you put on the sparkplug and the wire to the tester and see it light up.but I did not do the visual ark test to see a blue spark.I check that out tonight if I can I was also looking to get a spark trster thay reads how strong the ark is but havent gotten it yet.