97 4 door 2wd 100k miles 4.3 v6 blazer wont turn over.

on freeway driving home engine seemed to almost choke on something like it was having an epileptic seizure. let off pedal back to normal for a couple seconds/minute ~ I increased speed slowly began choking again intermit spazzing, as i drove. PARKED in driveway shut off... dead ever since. assumed it was a fuel clog. checked fuel system, W/ at least what i am familiar with√.
key on 56-60 pounds fuel pressure√.
new battery√~
charged√.
cranks but refuses to start.
has good spark√.
wont turn over even when spraying starter fluid into throttlebody√.


took tank down cleaned and pretty√
re-installed tank√
busted stupid fuel vacuum gadget on top of tank√ replaced √
reinstalled tank√
pressure 60+- √ ,sparks√
but wont turn over *(&*^%@

screaming punching and fighting a punching bag for like 2-4 hours√
checked pump√
tank down√
reinstalled pump √
pump was replaced and perfect like two months earlier√,
replaced filters√,
lines√,
fuel pressure at 55-60 refuses to turnover.
spark good√

hooked up code reader could not get codes. sort of told me there were 5 issues but would not give actual codes.

told me:misfire, cat converter, 3 sensors_fuel oxygn & exhaust, but there are like 3 of each?which one?) a few days of dicking around with issues and disconnected battery at some point. did not realize 97s apparently erase all codes until running again? cant turn over to diagnose cant diagnose to turn over. good times.


a clue maybe? i had lost my gas cap and did not realize for a week or two and only noticed when tank needed refilling but could not or did not replace for another week or so when this occurred. gas cap still not on could this be part of the problem.?


i am stumped help? please thankyou

 

Try holding pedal all the way to the floor and crank it for awhile.

 

Is the distributor rotor turning?
Perhaps check engine timing...maybe timing chain broke, slipped a tooth...???

Odd that wil not start with starting fluid if spark is good....???

 

Gas cap would give you a check engine light but would still run and drive.

 

Put a cap on. The pressure in the tank not being correct might cause some kind of fuel management issue with the computer.
It sounds to me like the original epilepsy could well have been moisture in the fuel from no cap.
At this point the computer may not know what the hell it needs to do with fuel management.
Put a cap on and hold the pedal all the way down, this will shut off the injectors. Crank it for awhile. This will clear whatever oddball mix of crap air/fuel/water you have going on in the cylinders. Then try starting as normal. I think your problems all started with moisture, doesn't matter how dry it's been.
Lanny's concept could also be right, I have felt the seizures a car goes through as something begins to effect timing.

 

Sounds like a problem I have with my manual a lot, it won't crank until I find the sweet spot in the pedal. Clutch adjustment perhaps?

 

thanks for all the advice i put new gas cap on√, replaced battery√,starting fluid throttle body and floored it. cranked it over about 15 times ~and wow it almost started one time. kept trying never almost started again? ill keep trying but i dont have much experience with rotor or timing any help on how i would proceed with that would be greatly appreciated. thanks everyone

 

darque: how did you test for spark?
Are you able to take the distributor cap off? Do say carefully as the two torx screws that hold the cap on screw into plastic which easily breaks.
What is the condition of the coil and plug wires? How old, any cracks, etc?
How old is the ignition module?

 

ignition module? meaning the part attached to the steering wheel area? of all the random damn things that ive done to this truck that one takes the cake. i replaced it like 3-5 years ago; give or take a yearish. plug wires & coil ? honestly i dont think ive ever changed em? if so 5 years ago minimum... yes i remember it was many many years ago. ok, i get it ill change the cables and look into coil will do... i do know #6 spark plug keeps getting gummed up should clean that, but all these things to me seem like they would make this run crappy yet turn over and run at least. timing issue ok ill check to see if dist center is turning, maybe at least i could tell if i slipped or broke a belt or tooth. i dont have a light or experience with that tho... ill reply back few days
thanks

 

oh ya forgot how did i make it spark? . i took cable off, grounded it. its spark was not perfect but i would swear good enough to spark ignition. ? coil, wires, cap and check next. thnks again lanny.