Neon no spark.

[ShadowBrad]

Just redid the head and timing belt on a 2002 Neon. I'm getting no spark when trying to start it. I have +12v at the coil pack when cranking, but nothing in the run position. Upon testing with a noid-light there is no pulse from the computer to the coil pack either. I replaced the cam sensor with a known good spare I had lying here and still no go. I quadruple checked all wiring connections and I was nowhere near the crank sensor when doing the work. When I reconnected the battery I did negative then positive. Any ideas what may have happened? Thanks in advance.

-brad

[turbovanman²]

Cam timing out? Common to do.

Do you use the proper intake cam. By chance, did you pop a fuse when you did the work?

[shadow88]

If it ran before you started, I'd check the cam timing.

[ShadowBrad]

I can check it again, but I checked it about 30 times when I was putting it together just to be sure. There was only one mark on the cam gear that I seen to line up with the mark in the plastic part of the timing cover. Also there are no codes besides the battery disconnect. If the cam timing was off wouldn't I have a code for the cam/crank sync problem or something of the such? Checked all the fuses also.

[turbovanman²]

I thought both cam gears had marks that faced each other?

Need to look at my book at work to be sure. You have the cam gears facing the right way?

[shadow88]

I thought both cam gears had marks that faced each other?

Need to look at my book at work to be sure. You have the cam gears facing the right way?

If it's a 2002 then it's a single cam engine. I don't think you can flip them around or the cover doesn't fit on.

[ShadowBrad]

Shadow88 is correct. SOHC engine, non-magnum. And no the gear can't be put on backwards it wont even bolt to the head that way. I checked the cam timing again and it's bang on. I checked the ASD and all the other relays and all the fuses and they are functioning. I've narrowed it down to the coils aren't getting the ground pulse from the PCM to fire them. The PCM is right in front of the trans and the plug that contains the wires for the coil and the fuel injectors was soaked in oil for some reason, I cleaned it all out and still no go. The fuel injectors are firing though because I pulled the plugs out and the cylinders smell like gas, but still no spark. I was wondering if that plug being soaked in oil could have shorted out the coil drivers or something? I'm going to take the PCM right now and go try it in my mother-in-law's neon, it's the same year and model, neither car has a security system. Would there be any problems in trying this? I still have only the "battery disconnect" code showing on the odometer when I flip the key on and off 3 times. The PCM is showing codes though as it showed an ASD Relay code when I had the relay unplugged when I was testing it, but that code disappeared as soon as I plugged it back in and cycled the key again.

-brad

[shadow88]

No spark is varified by removing and grounding a spark plug while attached to the wire, while cranking the engine? Just being sure.

[turbovanman²]

Gotcha, wasn't sure if was a DOHC engine.

PCM's should work.

[Mopar318]

The only DOHC on a 2nd gen neon would be an SRT4....hehe.

[ShadowBrad]

No spark is varified by removing and grounding a spark plug while attached to the wire, while cranking the engine? Just being sure.

It's all good. I know how to check for spark. I was a mechanic for a while and have been working on cars since I was 12 years old. After I found out there was no spark at the plugs, I unhooked the coil pack wire and checked the pins with a noid light and a volt meter and that's how I determined that I wasn't getting a ground pulse from the PCM.

On another note. I swapped the PCM into my mother-in-law's car and the car fired up ran for 10 seconds then shut back off and did that every time. I'm pretty sure I read that is normal behavior when the dash odometer does not match the odometer in the PCM. If that's true then my PCM is fine and I have a problem somewhere else. The only thing I can think of is the crank sensor, although I'm unsure of how it would have gotten broken since I wasn't anywhere near it when I swapped out the head and timing belt.

-brad

[Mopar318]

If your not getting a pulse from the PCM then I would suggest the Crank Sensor. It will have spark with a bad cam sensor, but it will not with a bad crank sensor. I would also be sure your not missing any ground. Since the spark is grounded through the head, make sure you are not missing the ground cable that attaches from the head to the body. Good luck!

[ShadowBrad]

Thanks guy. I just probed the Crank Sensor signal wire with an LED light. I'm not sure exactly what kinda signal is supposed to come from it, I'm pretty sure it's a hall effect sensor since it has an 8v feed, a ground, and a signal wire. With the LED attached it flashes while cranking the engine. I'm going over wiring diagrams and ---- right now trying to trace back all of the sensors and stuff I had unplugged. I've checked the grounds 100x over. The ground from the head to the body is in place, the one from the passenger motor mount to the body is in place, the ground by the starter and the one under the battery tray are all where they should be and they all are actually grounded, I've checked them with a multimeter.

-brad

[Dodge Aries K]

I personally think the PCM is bad. It shouldn't run for 10 seconds and then die in the other car. That behavior doesn't make sense.

[turbovanman²]

What happens if you put mother in law's pcm into your car?

[ShadowBrad]

Edit #2: I've figured it out. The new head was from a 2003 the car is a 2002, 2003 they switched the PCMs to a different style. The magnet on the end of the cam in 2003+ has many many N/S poles on it, the magnet on a 2002- has only 4, 2 North, 2 South. I'm going to swap the magnets now. Wish me luck...

-brad

---------- Post added at 03:52 PM ---------- Previous post was at 03:50 PM ----------


I personally think the PCM is bad. It shouldn't run for 10 seconds and then die in the other car. That behavior doesn't make sense.

I've heard of this behavior in SRT-4's and the fix is to have the dealer program the proper code into the PCM so that it matches the car. I was wrong about the security system, the car I'm working on does not have one while my mother-in-law's car does have a factory security system which is what causes the problem from what I was told.

-brad

[ShadowBrad]

Well...Swapping the magnet out fixed the start issue, but apparently since I put the computer into the other car it fudged up the mileage programming. I found info online that says when replacing the PCM that you have to take it to the dealer with the 4 numbers from your old one, the VIN number and the mileage and have them program it properly for the car. So I guess that's what's next on the list. After fixing the magnet the car fired right up and would run for a few seconds then die, after 5 starts it's completely dead now, won't crank nothing. From what I've been told that is what is causing it.

[shadow88]

Nothing personal meant. I don;t know everyone by name nor do I know your level of abilities. If you have a SKIM key, you're stuck going to a dealer for the code and reprogramming.

[ShadowBrad]

Oh don't worry man, I didn't take it personal. It's really hard to convey "tone of voice" over the internet so I just try my best. Yeah I'm getting ready to call the dealer now and see what's up with getting it programmed. Thanks for all the help guys. Much appreciated.

-brad

[turbovanman²]

So I was right, lol, it was the cam, :p

[ShadowBrad]

Haha...Indeed. Thanks to Aries_Turbo for the massive PDF manual he linked me to for the car and you guys for helping out or it would probably still be sitting. Lol.

-brad