04prixgt04

Hi everybody. I'm going to post this and simultaneously read some of the old posts. Been googling my head off too. My buddy's cavalier is stranded. It had a code for multiple misfire. I changed the coil pack assembly. The fuel pump is definitely working and there is fuel pressure. Battery and alternator are great. Check the ignition fuse and it is good. Not sure where to go from here. Any advice would be very helpful. Thank you

oilcanhenry

Fuel pressure is 55 to 62 PSI. You'll need a gauge for that. Injectors wont operate on a low PSI.

04prixgt04

Oh snap. Well I just saw a video on YouTube where they took the cap off the Schrader valve and depressed the nipple. When I did that it sprayed out like crazy. And I can hear the fuel pump running. But I do understand what you're saying :-) he said it was running a little shoddy then it just totally stopped. It doesn't even try to start a little bit. I mean it cranks and turns over like crazy but you don't hear any sign of ignition. But are you saying I'm kind of at a standstill until I check fuel pressure?

tech2

remove the air intake to access the throttle body. spray a 5 second shot of brake cleaner in the throttle plate while cranking...if it starts...the problem is fuel related.
if it still doesn't start...check for spark. the ignition modules go bad

04prixgt04

Would it do anything at all if the crankshaft position sensor was bad? Like what it even attempt to start other than cranking? Thank you and I will do exactly what you said a little later today.

tech2

if the crank sensor was bad; should be a code. bad crank sensor would result in a crank, no start with no injector pulse. if you are seeing rpm signal on the scan tool crank signal should be good.

04prixgt04

All right so I went ahead and just swap the crank position sensor because I don't have a code reader good enough to read the pulse live. I also sprayed the starter fluid straight into the intake for 5 seconds a few different times. No change at all. I'm going to get a spark plug tester tomorrow to check ignition but I'm guessing there's none since the starter fluid didn't do anything.

tech2

since you swapped the crank sensor....after you get it running....you will need to have someone with a good scan tool perform a crankshaft variation learn or the car will set false misfire dtc at high rpm.

oilcanhenry

Yes I am. Might be able to rent one at an auto parts store. Also heed tech2's advice. He is a full-fledged professional tech.

I am older, but have lots of experience and studied to be a tech but wound up as a professional class A driver and petroleum salesman. I am an expert on auto A/C systems, but know many other things, as well including fuel injection systems.

Jiyu

Spark and gas. This ain't rocket science. Pour a couple small spoonfuls of gas down the throttle body or shoot a small amount of starter fluid in there and hit the starter. If the engine fires, runs for a sec or two, you've got a fuel supply problem.
If it don't fire with gas poured into it, you gotta spark problem.
Pull the plugs, see what they look like. Lay 'em on the head (to ground them) crank the engine and see if they spark.