I just bought a 1998 1500 4x4, and it wont start. Im getting air, fuel, and spark. it will crank, but it won't fire. Ive tried nearly everything i can think of. replaced the crankshaft positioning sensor and still nothing. cleaned the dist. cap. there is definetly spark. if i spray starting fluid into the throttle body it wont even attempt to fire. any ideas?

 

Did you check for spark at the end of the plug wires? What do the plugs themselves look like?

 

Unscrew the precat o2 sensor and I bet it fires right up.

 

there is definetly spark.

Ill try the o2 sensor. ill let you know if that works.

 

Why would the 02 sensor help?
It doesnt make sense. there is air, fuel, and spark in the combustion chamber there is no reason for it not to fire right up...

 

also try opening the throttle body plate by twisting the plate open, or pressing the gas pedal.
try this with and without starting fluid.

if this helps, it indicates a failed Idle Air Control (IAC) motor.

 

unscrewing the O2 sensor allows a clogged cat converter to breathe, which is another common problem on these trucks.

 

Spark where? Did you do the O2?

Did it start?

Was any work done to truck since the last time it was running or just before?

Re check the distributor cap. Do NOT loosen distributor and turn it.

Why did you change the crank sensor?

 

Update- I tried the o2 sensor. Still nothing. Brand new cap & rotor. The spark plugs are making spark, won't fire with starting fluid in the TB. Compression is at about 150 for each cyl, when cyl 1 is at TDC the rotor is pointed at that plug wire so that means the timing is on, right?

 

The plugs are sparking.