I was driving my 95 SOHC Neon a week ago and it just started to loose power and ended up dying. I checked for spark and it is not sparking on the two center cylinders. I tested the coil first thinking it was a simple fix, but it meets the specs from the manual.

The check engine light didn’t come on, but I later found out the previous owner had taken out the light bulb (thanks). Needless to say, I had disconnected the battery before I realized the bulb was missing, so I wiped any codes that may have been present.

I replaced the spark plugs & wires (it was time), camshaft sensor, crankshaft sensor and swapped the coil with another one and still have the same problem. I checked the three wires from the coil to the PCM and they test good, no breaks or shorts. From reading the forum, I decided it was probably going to be the PCM. I went to the junk yard and found a computer that matched my year/transmission/SOHC. But after replacing the computer, I still have the same spark problem.

I did notice that after I swapped the computer, the first time I crank the engine, it will spark all the cylinders, but the two cylinders that weren’t working appear to spark about half as fast as the other two. Usually after the first crank the two center cylinders will no longer spark. Sometimes it will go two or three cranks but the two center cylinders always spark at half the rate of the two outside cylinders. If I unplug the computer, wait a couple of seconds, reconnect it again, it will spark the center cylinders again for a crank or two.

Did I get a computer with exactly the same problem? Any ideas or suggestions?

Thanks very much!

 

Sounds like a bad coil pack to me.

 

get a code reader if it is misfiring you should throw a code quite quickly. Itll give you the code and start from there. Also buy a new coil pack and wires to the ecu you could have some issues w/ wiring if the problem still exists. Also check the grounds make sure they are solid. Check your gap as well prepackaged plugs are set for sohc but not for dohc they usually need to be gapped more for dohc. since you are sohc check anyways. Also as far as motor goes make sure the threads arent screwed up to where someone overtightened b/c this can cause problems as well. Check your compression and make sure you are getting the correct amount of fuel pressure from the rail and injectors.

 

The coil pack is seperated into the two noticeable halves and it sounds like your coil is half shot. You can either get another from the junkyard or you can get the MSD coil which as the exact same output as the stock coil. It will run you around $69.99 and you can get it at Jegs or most any other performance shop. Here is some more info as well as another place you can get it from: http://www.modernperformance.com/dcx/msd_coil.shtml

 

yup ....get a new coilpack 1st.

 

I did give another coil a shot thinking it might be the problem. The second coil was from the same junk yard that I got the PCM. It test ok with an ohm meter using the Haynes specs. It did the same thing. Thinking it may also be a bad coil, I removed all the spark plugs, swapped the left and right outside wires at the coil pack connector, cranked the car and the problem moved to the opposite two cylinders. Since the problem moved when I switched the sides and the coil was able to spark the cylinders that weren't working, I thought I had proven to myself that it probably wasn't a coil problem. I am pretty sure the coil pack isn't getting the proper signal on the side that sparking the #2 and #3 cylinders since the problem moved with the signal wire.

I gapped the spark plugs at the specs from the label on the hood, I think they were supposed to be 35 thousands if I remember correctly. The compression on each of the cylinders are pretty close to each other and the plugs are wet with fuel when I take them out. It appears that it is just a spark problem with the two center cylinders. I will get one of the MSD coils ordered, sounds like a good idea to have a new coil anyway. Thanks for the link!

I am going to show how little I know, but will the scanner show codes that aren't being displayed by the check engine light? I ran the on-off-on-off-on sequence and the only codes that show up are the 12 for the PCM reset and 55 for the end of codes.

I will check all the grounds this morning, thanks for the suggestion.

I really appreciate your help.

 

Well then the only thing that's left is to find where the wire is broke and fix it or replace the harness.

 

I know this thread is old, but I am having the EXACT same problem with my 96 soh neon. Anyone got any other ideas?