Chrysler Repair: Stalling 1994 New Yorker, spark plug wires, dark location

Question
Great reasponse, thanks.

I have the 3.5L engine and have run the diagnostic codes you provided. The codes returned are "11" and "12". I replaced the battery about 1000 miles ago and have had all conditions described in my original email since then.


Plug wires look good--not newn but no cracking--they are Mopar and I'll need to check, but think they have been replaced in the last 30,000 miles.

Any thoughts based on this new info?

John-------------------------
Followup To
Question -
have a 1994 New Yorker with 226,000 miles on it.

Car began stalling this winter. First few episodes it would stall, die and then start after 10 seconds to two minutes of cranking.

Now it stalls in one of three distinct ways:

1) Stalls while driving - RPM's go to zero and
engine either fires up again or requires a
restart. Frequency - 1-2 times/week

2) Stalls after driving. Car simply won't start
after a short drive. Several minutes of
cranking will get it to start again. Frequency- once every few months

3) Stalls when starting. Sometimes the engine
catches, then stalls. Frequency - several
times per month.

Changes in humidity may or may not cause stalling frequency to increase. It seems like during very humid periods (rain, immediately after rain or snow), problem is more frequent.

I love this car, but my wife is going to demand I buy a new one if I can't fix the problem. Any suggestions?
 

Answer -
Hi John,
Thanks for the detailed history which is helpful. There may be a couple of reasons for what is happening. The humidity observation implicates the spark plug wires as having compromised insulation so if these are the original wires that would be a reason for renewing those. You can often visualize the breakdown on a humid evening in a dark location when you open the hood and see the light show from arcing of the wires to the engine metal ground points. Also look at the other ends of the spark wires at the coil to see if you see arcing of the plug in towers themselves. The breakdown of insulation at the towers is cause to replace the coil but that is an expensive part so don't do that without a real indication of damage.
The other diagnostic tool is to take advantage of the on-board ability of the engine controller to recognize faulty electrical behavior.  It may pbe possible for you to ask the engine controller whether it has observed any failures in the many control systems and that are stored as codes in its memory. 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 several engines and we can look up the possibilities of what is wrong based upon what fault codes you show. When you write back tell me which (3.3 or 3.5L) engine is in the model of Chrysler your wife is driving driving.
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. So write back with the fault codes.
Roland

Answer
Hi John,
The code 11 is consistent with the problems you have been having, namely the hall effect sensor used to monitor the position of the crankshaft so as to provide spark timing is breaking down, then recovering, etc. That is located on the left side of the engine near the seam between the engine and the transmission because it is placed in close opposition to a ring that is attached to the flex plate that in turn is attached to the cranshaft at that interface. It has three wires (orange, black/light blue, and light blue/dark blue) so you can identify it. It is held in place by  bolts. A new one will have a paper spacer on the end of it which you should leave in place when you intstall it, just put it in till it touches the ring. Tighten the bolts to 105 inch-pounds.
Check that the wires and plug are in good shape and if they are then probably you will solve the problem by replacing that sensor.
Roland