just bought this car a month with a 140k ran good until i changed the power steering pump. now i have no spark at all so far it cranks fine but wont fire.

ive checked

timing belt

changed cam and crank sensors and check 8v. and the signal is fine

has fuel pressure relay and fuses are good

asr relay works

coil has 12v from the middle wire and from the sides when cranking

checked all the wires and grounds nothing wrong

how do you tell if the pcm is bad because i dont get any codes at all with a scanner. none of the sensors show up as an error and i dont get a code 12 after disconnecting the battery. so i think this may be the problem is their a way to test it?

thanks for your help

 

So you have +12 volt on all the coil pigtail wires? Use a scanner that can data log or watch sensors. Flip the key to on and see if you can read the sensors. Usually I confirm the ecu is bad this way, and after I have checked everything else possible. Do you have fuel pressure? Are the injectors firing? You say you have the sensor voltage at the pigtails from the computer? Coil pack been checked?

 

Also see if you can hear the fuel pump is priming it self. You could have blown fuse or your fuel pump may have crapped out

 

i can hear the fuel pump prime and the pressure is above 40psi.
i swaped the coil pack with a junkyard one still nothing. both coils test fine
on the coil pigtail i put an led light on the switching parts when im cranking it you can see it flicker and on the middle post it has 12 volts.
just tested the compression all of the cylinders are between 150 and 170.
im going to check the injectors next. im really confused because everything looks fine and it should have a spark.

i just tred a new pcm same exact model still nothing.

 

The crank and cam censors might be getting power but doesn't mean they are functioning properly

 

Check injector pulse. No pulse there is an issue with the ASD. (dark green/orange wire)
Do you have ground at the coil? If the coil is getting everything it needs to fire, and no spark comes out the other side the coil is the issue.

 

I figured it out finally after reading alot of posts on here. I took the wiring harness out to inspect it and just behind the cylinder head next to the exhaust. and found that the coil power the orange power to the sensors and all of the grounds were melted and fused together. so I patched up all the wires and insulated them and it fired rite up. I'm lucky the car didn't catch fire while I was driving it before.
Thanks for all the help

 

i have a 99 neon that i got the used motor out of a 2002 neon .. all the sensor on jthe harness plugged right up and i get power for a sec to the coil pack then nothing .. any ideas on what can be wrong .. its not throwing any codes either ...