No were in your question did you say if you had checked for codes in the computer. check this now it may help find the problem. this should have been done in the first place and you wouldn`t have spent all that money on none required parts. it could even be the computer gone bad.
SOURCE: my 1996 cavalier Z24 wont start
pull a wire and ground it via useing a screw driver at the end of the spark plug boot to check for spark / if their is no spark / ignition control module / there is also a crank shaft position sensor / located on the back side of the motor under the coil packs / pain to get to / also the nuetral safty switch / to check the neutral safty switch diconnect the big harnest at the neutral safty switch put a fuse tester to the yellow wire / have someone turn the key / with the tester grounded the light should come on / now we know the ignition switch has power going through it. if there is a no power at the yellow wire / bad ignition switch / does the car have a relay located at the top of the radiator core support (up by the radiator looking down drivers side)if it does not gm will install one for free / if there is / look for the purple wire coming out of the relay and Follow it down to the starter / reconnect the neutral safty swtch / touch the small S (the smallest screw) terminal on the starter soilenoid / have someone turn the key forward check the light / this will detemine if the relay is good / CAREFULL NOT to touch the big starter wire with the little one it will jump the starter / I HAVE THE SAME CAR / Hope this helps
SOURCE: cobalt no spark
I was going to say crank sensor, but you changed it. What have you done to it latley? Or did this just start? I kinda want to say PCM for some reason. Any welding done on the car latley?
SOURCE: 2000 chevy C2500 wont start. No spark. Replaced
Did you check for codes. It won't matter what you change if your computer failed. You should of payed the diag fee. You would of saved alot of money.
If your engine cranks normally but will
not start because it has no spark, or it stalls and won't restart because it
has no spark.
You can also do a test to confirm the
problem .The procedure to do the test is as follows:--- If your
engine has spark plug wires, disconnect one of the plug wires from a spark plug
and place the end of the wire near a metal surface on the engine. Then insert a
small Phillips screwdriver into the end of the wire (the plug boot), or a small
bolt or nail to provide a conductive path. Then crank the engine and look for a
spark to jump from the screwdriver, bolt or nail in the end of the plug wire to
the engine. If you do not see a spark, there is an ignition problem. OR----------- If your engine has a
coil-on-plug ignition system with no plug wires, In that case remove one
of the coils from the spark plug and insert an old spark plug, a spark plug
tester or a screwdriver into the end of the coil. Ground the spark plug or plug
tester to the engine, then crank the engine and look for a spark. No spark
indicates an ignition problem.If the engine has no spark, check for
voltage at the coil positive terminal when the ignition key is on. If NO
voltage, then problem is on the trigger side of the coil (pickup, crank sensor,
ignition module or primary wiring circuit).
But If there is NO voltage at the coil
itself, then in that case the problem is on the supply side (the ignition
switch or ignition wiring circuit).-----------------
Jeep cranks but no start:---------------- A jeep that cranks over but doesn't start, in many cases will be
due to a bad fuel pump, a broken timing belt, an inoperative cam sensor or
crank sensor. Also these problems are related to faulty spark plug. Check the
spark at spark plugs when you start the jeep. Do you notice any spark. Actually
you should see. If in case there is no spark then it's a spark plug problem.
Also the coil pack gives power to spark plug. So check the voltage at coil
pack. It will show 12 volt. If there is no voltage noticed at coil pack then
its faulty coil pack that has to be replaced. If all the possible options
checked out ok then check the car starter. The starter gets power from battery
to start the jeep. If the starter is faulty then it will not let the car to
start. Also check and confirm that there is fuel in the jeep. If its very low
fuel then in some cases this causes the problem. Also check and confirm that
fuel pump is functioning properly and the fuel filter is not clogged. One of
the easiest ways to check for a fuel pump related problem is to spray a little
starting fluid into the air intake while trying to start the jeep. If the car
starts momentarily, then there's a good chance the fuel pump is not working or
the jeep is out of gas. You can also listen for the fuel pump's humming sound
when the key is first turned on. Also if a inoperative fuel pump is suspected,
a good technician will always check to verify there is power and ground being
supplied to the pump, to eliminate the possibility of a bad relay or electrical
issue. Fuel pressure can be checked with a pressure gauge and if there is
pressure, pulse can be checked at the fuel injectors in several ways including
the most common, with the use of noid lights. If the injectors don't have pulse
the engine won't start. ---------- This troubleshooting tips will help you to solve the problem. Thanks.
Helpmech.
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In case anyone else has this issue, here's what caused and fixed the problem.
The problem was the key on the camshaft had sheared and would occasionally catch and allow the car to run.
The solution was to replace the entire engine block. (Replacing the cam was a temporary fix, but either the valve lifters or cam bearings were sticking which caused the problem to come back.)
The best engine block to use would be from a '94-'97 Cavalier which has the roller cam instead of the flat tappet cam. That will lessen the stress on the cam and extend the engines life even under conditions similar to the original failure. -- Might as well shim the oil pump to increase pressure in case of an internal leak causing bearing seize.
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