QuestionQUESTION: Hey i have a 1996 Concorde 3.5L, the car will intermittently not start, when it does start it runs fine. I had the cam shaft and crank shaft sensors replaced, along with the egr valve because the car had a check engine light for that.(No engine light currently) I though i had it remedied but it wouldn't start on me this morning. While in the shop (the other day), they said it wasn't getting fuel or spark when the car wouldn't start. So they replaced the cam sensor and we though it was fixed. Order of repairs were 1-crank sensor 2-EGR 3-cam shaft sensor. Any ideas?--Thanks
ANSWER: Hi Andrew,
If both the fuel pump and the spark are absent, then I would suggest that either fuse 18 in the box behind the dash has a crack in its wire that makes it fail intermittently or the output of the ignition switch to that fuse is missing. So with a voltmeter or 12V test light you could check both sides of that fuse the next time it won't start to determine if there is voltage on both sides. The voltage is what is necessary to actuate the ASD and fuel pump relays in order to provide voltage to the coil pack and the fuel pump. So while you should have a signal telling those two relays to close coming from your crank and cam sensors, if there was no voltage on the other end of their actuation coils you would not have the relays actually closing and powering fuel and spark action.
Roland
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QUESTION: Yea thanks for the quick reply, the car is starting up for me this afternoon so i will have to wait to check any voltage, but at a glance the fuse 18 looked okay. Is it possible for the relays themselves to go bad? The auto shut down or the fuel pump relay? I forgot to mention the car was randomly stalling on me and also having the hard starting, but post egr replacement i have had no stalling only the no starting.
ANSWER: Hi Andrew,
Sure, the relays can go bad, but those two are independent of one another so you wouldn't likely lose both of them unless there common power for their coils failed, or they didn't get a go ahead from the computer because it wasn't getting the sensor signals.
When it next fails, listen for whether the fuel pump runs for about a second when you first turn the key to run, and check for spark while cranking it over. If only one or the other is absent, then the relay theory would be worth pursuing (by switching out the relays).
Roland
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QUESTION: Okay, so the car was starting up for me yesterday as i said. This afternoon i went and the car started right up no problems. So i drove the car around a bit, let it warm up, then stopped for a few gallons of gas. Car started back up fine, then as i was leaving the station i notice it started idling rough, and on take off it would not be smooth, the engine was "rumbley" like an unbalance or a misfire possible. As i got back home, just up the road, i parked it and while idling, if i revved the engine, it would not be smooth but "rumbley" off idle, it seems like a misfire. Could this be at all related to the no starts? There is no check engine light.
AnswerHi Andrew,
You said "no check engine light" which is not the same as no fault codes in the PCM memory. Use your ignition key to get the 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 to make sure you get a repeatable set of counts. Then combine the counts in pairs in the order of appearance to form the two digit fault codes. Go to www.allpar.com/fix/codes.html for a code translation or write back and let me know and we'll go from there.
Roland
