QuestionQUESTION: I have a 93 Concorde 3.5 that just won't start. I thought and was told the computers were bad so I replaced them. Well the one under the air box and the one behind the glove box. Then found that some of the wires in the bundle under the radiator had been worn through or cut or even burnt. I have fixed these. Upon doing so the car fired right off and ran like a champ. I drove it home, it idled for maybe 1 hour total in addition to being driven for 20 minutes. The check engine light never came back on. I replaced the thermostat later that night and when I went to start it.....NOTHING! I have no codes coming from the PCM. I have changed the fuel pump, cam shaft position sensor,some relays, throttle position sensor. I have fuel coming into the rail and spark coming from the coil pack. I was able to get the EGR valve to move so it is operational. I don't know what to do anyore. It will turn over and sometimes sounds as though it begins to start and the RPM's will hang at about 100 for 1 to 2 seconds.
ANSWER: Hi Ronnie,
Tell me the exact sequencing of the all repair/replacements and at what point it ran, and it what point it didn't run. This could be relevant. Start with the last time it was running well and a little of the overall history of the car, then what/when it stopped running and go on from there in sequence. Thanks.
In the meantime, have you tried cleaning the throttle body throat, both sides of the plate, and air by-pass passageway?
Was the "computer behind the glove box" the one with a 21-pin natural color plug? If so, and you disconnected it without having the engine running then that is why it won't start. It is the anti-theft module and the engine has to be running when you pull its plug or the pcm goes into a "hard" shutdown in which it will start and run for about 3 seconds, then cut out. If the engine has not run since you changed that one out, then I think you will need to get a dealer to clear the anti-theft module/pcm interface using a Chrysler DRB II unit.
Roland
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QUESTION: Car would not start. Replaced Computers,TPS,Fuel pump,and cam shaft sensor,still would not start. I then checked the wiring and fixed it and it fired right off. Drove it home and changed the thermostat. The head lights began to flash when I tried to start it. Would crank not start as I said. My father told me to try putting the original fuel pump back in so I did with the same result. My father was then told to have me put the original computer from the glove box back in so I did. I got the same result: the head lights will occasionally flash (will do so more often than not), will crank but not start. I am still getting no codes from PCM.
ANSWER: Does the engine run for a couple of seconds, and then does the spark die? Is there a theft alarm LED light on the dash, and what is it doing, if so? The headlights flashing (and also the horn should sound, is your horn working?) are a sign of the theft alarm going off. The quick die after starting, if consistent in length of time are symptomatic of an alarmed theft system. So you now have both original pcm and theft alarm module in place?
Try lock/unlock both front doors to see what effect that has on the LED. If none, then let me know and we can try doing the same thing as lock/unlock right at the theft module proper by jumping a couple of wires.
Roland
---------- FOLLOW-UP ----------
QUESTION: There is no LED light on the dash that I see. The horn does not blow when the headlights flash. The horn does however work. I have both matching computers in place. I can sometimes make the lights stop flashing by locking and unlocking the door but not always. Even without the lights flashing the car will still not run. Thank you by the way for all of your help so far!
AnswerHi Ronnie,
I can't tell for sure if you have the theft system or not. You didn't answer whether the module above the glove box had a 21-pin natural color plug or not? The horn should sound too, however, if it has the alarm. You didn't say if the car cuts off after starting in exactly the same definite number of seconds or not. Does the spark or fuel pump voltage cut out at the same time as the engine dies, or does that voltage continue on for about 1 second after it dies? The former would indicate an alarm system is what is cutting off the engine.
There is supposed to be a security alarm system lamp on the dash. But you say there isn't one so that is curious.
How long have you had the car, and did it ever behave like it has an anti-theft system?
Let's try to resolve this part first, and if there is not an alarm then we can consider all the other possible reasons why it won't start.
Roland
