Question-------------------------
Followup To
Question -
I have a 1995 Dodge Neon with 115K miles on it, 5 speed, single overhead cam, base model. The car did run great but now it will not start, it will turn over but not catch.
The same thing happened previously and I thought it was the coil and I replaced it with success for about 6 months but it started to hesitate and eventually would not start, same conditions as above.
The last coil I installed did the trick for about 2 weeks and led to the conditions above. I tested the primary and secondary resistance on both coils and they apprear to be in the proper resistance range suggested by an auto repair manual and now have second thoughts about it being the coil.
When it happened the last time with the 2 week coil initially it happened but I played around with the coil and it started after about 1/2 hour, got me home, it tested it by starting it 4-5 times and it started fine, but when I tryed to start it in the morning would not start. I tryed the older coil which I replaced about 6 mo. ago and still would not start.
Any ideas?
Thanks, John
Answer -
Hi John,
I just realized that your controller may be set up for the OBD-II code system, which doesn't readout with the ignition key, but give it a try. If not, then a code reader will need to be plugged into the jack that is under the dash to get the codes. So let me know what happens.
Roland
It would be useful to actually check whether you are getting spark at a plug. So get a spare plug and then pull one of the caps off one of the installed plugs and put the spare in the cap. Then hold the threads of the plug against the cylinder head and have a helper crank the engine so you can observe whether or not you are getting spark. If you don't get spark it may be the coil, but not until you eliminate all possibilities. The most useful thing to do would be to try to get the fault codes that may stored in the engine controller memory to readout. Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine'light will remain on when you leave the key in the "on" position with the engine still not running. But then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout".
I have the troubleshooting manual for your engine and we can look up the possibilities of what is wrong based upon what fault codes you show.
There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair.
Roland
Hi Roland,
I didn't get a spark at the plug at all and my check engine light would not come on so I couldn't check for code numbers. I checked camshaft etc. sensors that I could find. The one I couldn't find was the crankshaft sensor. As far as I could tell they were ok. Finally I wound up checking the connections to and tapping on the PCM module and surprise it started. I tested my older coil and it works fine also. So apparently it wasn't getting the proper voltage? (The check engine light came on also and gave me codes of 12 - 43 - 43 - 55 but with the PCM not working these may not be valid?)
I assume the PCM must be replaced and cannot be disassembled and repaired?
Thanks for all your help,
John
AnswerHi John,
Good work. The double 43 code is strange, but it may just be due to that PCM being OBD-II where the unit also will give P-(4-digit number) on a scaner and there are several such numbers that also are tied to the 43 code. All have to do with the primary of the spark coil not drawing full current.
So where do we go? It could be that the problem was related to the connections at the PCM rather than tapping on it? If that were the case, the no start may be solved. On the other hand if it isn't then you can possibly tap your way home in an emergency. If it does fail again in the same manner then the PCM would be suspicious of being bad. I assume that you have 2.0L SOHC engine.
The check engine light not working and no codes (earlier) may mean though that the voltage to operate the PCM was absent (which would go along with the 12 code except that you no doubt pulled the plugs that supply voltage to the unit so that also would set a 12 code). The voltage to run the PCM comes in on pin 20 of one of the 40-way black connectors (a switched source from the ignition switch powered by fuse 8 of the power distribution center) and on pin 46 on the other 40-way black (pins numbered 41-80) on a dedicated hot line from fuse 5 of the power distribution center. So you might want to check those fuses and the wires and contacts of those two power feed lines to the PCM. I would be inclined to wait it out to see if it is solved rather than jump to the conclusion that I need a new PCM. (By the way those fuse assignments may not be accurate, I am going by the '96 Cirrus/Stratus manual rather than a Neon manual. But both have used the 2.0L engine so I assume the circuitry is identical. The PCM plug assignments I am sure are identical.
Roland
