Chrysler Repair: 1996 Plymouth Gr. Voyager Computer problems, plymouth grand voyager, powertrain control module

Question
1996 Plymouth Grand Voyager:
I have had problems with my dash going out for years...it recently became constant.  Then the van would start and immediately stall. After leaving it with my mechanic for a week trying to get it to NOT start...it did it with the computer connnected.  It shows Fuel Allowed..NO
His explanation was the security system, which is controlled by the same faulty computer that controlls the dash. I replaced it, and 3 days later the dash went out, then 2 days later the van wouldn't start again.  I returned the computer and got another.  Here I am, 2 weeks later and the van will not start again. Sometimes it lasts for an hour, sometimes 12 hours.  The dealer says the only thing that it can be is the computer, but that it cannot be 2 computers that are "bad".  This van is not repairable!
Can you help me?  I know this is out of your range of years...but lets face it, a POS is a POS.

Thank you,
Melissa

Answer
Hi Melissa,
I believe that the problem is not with the powertrain control module (engine computer) but rather with the vehicle theft security system module. The explanation could have to do with a use of a booster battery to start the car, or if the battery spontaneously disconnects (due to a loose cable at the battery or a faulty battery), or a fault in the wiring of the security system. So I would return the unnecessary engine computer (that was an incorrect approach) and focus on either fixing or diabling the security system. By the way, if you replace the computer with the security system in place, the security system won't arm until 20 crankings of the engine. That may explain why it failed again after 5 days and after 2 weeks.
It is pretty easy to get around this problem. According to the manual if you don't use the system but rather lock the doors by hand, it won't arm. (But that might not be foolproof if the theft module or wiring is bad). The other way to get around the problem is the remove the theft module and get rid of the issue forever. But the trick to doing that is to disconnect its plug ONLY WHILE THE ENGINE IS RUNNING. It is usually located in the dash, behind the glove box, and the glove box often needs to be removed to get to it. It has a 21-pin connector and is 'natural' in color. If you want to still have a theft system, then the system will have to be troubleshot to determine if it is the theft module or the wiring or a sensor of that system that is bad. I don't think the dash light issue is related to any of these systems, so forget that matter. It can be dealt with once you get reliable use of the car.
Roland