Chrysler Repair: Engine Just Quits after 30 min. of driving, blade tip, philips head

Question
Roland:

Lesson learned... try the inexpensive solutions before the expensive ones!

I took the coil, MAP, TPS, IAC, IAT to a shop that had the ability to scope the components and all checked out fine.  

I desperation, I happened to look at the 02 sensor (which I had repalced less than 6K miles ago, and discoverd that the harness had a break in it.  

I replaced the o2 sensor and the problem cleared up.

Don;t you yearn for the "old days" when it was easy of diagnose problems?

Thanks for your help!

TB
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Followup To

Question -
Roland:

I have a 91 LeBaron with the 3.0L engine.  

Car runs & drives great - an then just quits after about 30-45 minutes of driving.  No CK eng lite, no erratic idle, no warning at all.

Let it sit a few minutes and it will start and drive again perfectly.

I've replaced the distributor and harness, fuel pump and relay and ECU.  

Can you think of what the prob may be?

Thanks!
Tim

Answer -
Hi Tim,
Immediately after it has quit, check for whether or not you have spark and for how many seconds of a 5 second cranking time:
To test for spark, remove a cap from one of the spark plugs by holding on to the connector cap and pulling on it (don't pull on the wire). Then use a screwdriver (a philips head is better than a flat blade tip) with a plastic handle to probe inside the cap so that the tip touches the internal wire deep inside which normally touches the tip of the spark plug. Then hold the screwdriver by its plastic handle in one hand and the cap in the other hand so that you maitain the connection between the internal wire and the tip of the screwdriver. Move the assembly to be within 1/4 inch of a main metal part of the engine such as the cylinder head. Have a helper then try to start the car while you hold that position of 1/4" distance and observe whether during the cranking a spark jumps between the shaft of the screwdriver and the engine metal surface. Let me know that test result.
If you don't get spark for 5 seconds, or if you don't have a helper along, but if you can carry a voltmeter with cables that allow you to put the meter where you can see it while you are in the driver's seat, then attach the meter leads to the dark green/black terminal of the spark coil and to a ground point on the engine. Then measure for whether you get 12v on the coil post for all 5 seconds of a 5 second crank.
Also, now read out the controller memory for fault codes:
Reading out the engine controller memory for fault codes is the first step. 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 the 3.0L engines 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. Let me know the codes and I can give you some direction. If there are no fault codes then the problem could be a spark issue.  
Don't crank it for more than 5 seconds. If you get spark for 5 seconds then that is o.k. and we will have to look further. If you get spark for 1-2 seconds or not at all, that is relevant to know.
So write back with the results.
Roland  

Answer
Hi Tim,
Thanks for that report. If you tried to readout the controller for fault codes you should have gotten a 21,51, or 52. In fact if you haven't disconnected the battery recently you should still find one of those codes stored. Disconnecting the battery for a minute or so will erase most stored codes, except 12. It is good that you solved it on your own.
Roland