Chrysler Repair: 96 Plymouth NEON cranks but wont run, plymouth neon expresso, plymouth neon

Question
Hi Roland,
I am trying to repair a 96 Plymouth NEON expresso with a 2.0L SOHC and manual transmission.  The engine will turn over but not start.  It acts like it is trying to start but kicks and backfires some through the intake.  I have verified that fuel pressure is correct and it is getting spark to the plugs.  I removed the timing belt cover and verified camshaft timing is correct - #1 piston at TDC and marks on camshaft sprocket and crankshaft line up properly and the belt in good condition.  I feel it is a timing problem.  There is a lot of history on this car and I don't have it all because it is my sister-in-law's car and has had an engine swap.  The crankshaft wiring has been spliced prior to me taking on the case due to contact with the exhaust manifold.  The car ran a couple of weeks after the engine swap and it just died. Many people have tried to get it to run and have probably introduced other problems.  I have redone all the splicing that occurred but am not sure if the wiring is correct to all the sensors and would like to know the complete pinout of which pin of the crankshaft, camshaft and coil pack that the wires go to from the PCM.  Maybe someone switched the coil pack wires around and is firing the wrong cylinders ?  The PCM has been replaced before as well and I tried anotherone from a junk yard but with same results (fuel, fire, no run).  The Haynes book is of very little help and I have been working on this for a couple of months now :(

Thanks very much.

Ed
Pensacoola FL

Answer
Hi Ed,
Have you tried the ignition key to get some fault codes?
"On-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains on, to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat until you have an assured accurate set of counts. Group the counts in pairs in the order of appearance. The last pair will be 5 in each, the number 55 which is the code for 'end of readout'. Then tell me the other codes or go to www.allpar.com/fix/codes.html for a list.
On the wiring, The coil pack 3 goes to pin 2, the coil pack 1 goes to pin 3 at the pcm, and the coil pack pin 2 goes the the ASD output 12V which you can access also at the alternator (dark green/orange). There is also a  "noise supressor" on that line near the coil pack and a capacitor on that line near the alternator, so check those. They should take a charge and hold it. The orange 8V wires on the cam and crank sensors pin 1 are from pin 44, the common grounds on pin 2 come from pin 43, and the crank signal is from pin 32 and the cam signal is from pin 33 of pcm.
This should give you some more to do :)
Roland  
PS Use the 'thank/rate' tab below to get back to me without having to wait for me to be available to take an answer. There is a space for comments, to which I will reply.

Hi Roland ! I really diden't expect such a quick response! I left the code part out of my original question - I got only a code 12 because I had disconnected the battery and code 55. I also borrowed a friends scanner which I already returned. I think it was an accuscan 6000. It showed no stored codes and gave me normal readings on the two o2 sensors, air temp and pressure, throttle position, etc. so I think the computer is working ok. I found the signal return wires and probed the crank sensor wire to the signal return and get alternation between 5v and about .15 volt as I rotate the engine by hand. I also checked the cam sensor line and I get the same result. I also noticed that If I disconnect the cam sensor I get no spark at all from the coilpack when I thought I would, just that it would not run well. Same thing with the crank sensor - disconnected no fire. I verified that the injectors are putting out - the cylendars seem to be getting the fuel because it will backfire and fight againse the starter while cranking. If I disconnect thye coilpack and crank it it turns over smoothly. The cam sensor has been changed but not the crank sensor because I got the signal I expected. I have also performed compression check and the results were #1: the lowest at 145, #4:the highest at 164 and the others between that. I will ckeck the wiring again with the info you sent me but other than that any ideas? IThis thing is driving me nuts trying to figure out! Thanks very much for your time!!! v/r ED


Hi Ed,
Thanks for the report. The two things that come to mind are first, that your timing belt may have slipped so that the cam shaft isn't timed properly to the crank; and second, that the exhaust system may be compromised by a plugged catalytic converter whose honeycomb may be dislodged/off-axis. The manual says to bring the #1 cylinder to the top of its compression stroke (using a dial indicator to detect when it rises no further) and then remove the access plug at the top of the outer timing belt cover to check that the mark on the sprocket aligns to the arrow on the inner cover. How does the catalytic converter look externally? Does it rattle (the sound of a loose honeycomb)?
I will be curious to know what gets this running for you. Thanks for the evaluation and nomination.
Roland