Chrysler Repair: 04 3.5 L cranks no start


Question
QUESTION: Roland,

last night I checked the cam sensor and had 5 volts when wiring was unplugged from sensor. now what should I check the other sensors too? Also should I check for  5 volts on pin 29 of the computer side (not wiring). Seems like I am missing something simple. Since the battery was low when the car died would I have a short somewhere. If so I do I find it.

Thanks,
Ben

ANSWER: Hi Ben,
If you have 5v on the cam sensor then you would also have it on the crank sensor because the 5v wires for them come from the same splice. And if you still have no codes (just see "done" in the odometer window?) then that suggests you would have spark. You hear the fuel pump when you turn the key to 'run' for about a second, and presumably it also runs when cranking it over (listen carefully at the tank).
So do you get any sense that the engine is almost starting or at least firing a bit when you are cranking it over? If so, that suggests the issue is the mixture is too lean which is often due to the egr valve not being tightly closed. That can be the case and it won't necessarily set a fault code. Let me know if you sense that to be the situation or not.
The issue of the battery draining is best assessed by measuring the "ignition off current" that is being drawn through the battery. So put an ammeter in the gap between the - post and the - post clamp after separating them and see what the current reads. It should be less the 50 milliamps.
Roland

---------- FOLLOW-UP ----------

QUESTION: It just cranks. Doesn't try to start.  Fuel pump runs when trying to start. Will check battery tonight

ANSWER: No start with no codes is tough. Problems with the mixture are most likely. Try cleaning the throat of the throttle body/butterfly plate/idle air passageway on side of throat and then consider removing and cleaning out the egr valve.

---------- FOLLOW-UP ----------

QUESTION: Hi Roland,

I am starting to wonder if I am looking in the wrong area. I do 5 volt reference at sensor and i was able produce spark at one of supplying 12 volts. Could it be a broken timing belt?  How do I check that?

Than

Answer
If the timing belt were broken you have interference between the top of the pistons and some of the valves so the engine might not even crank over and would probably produce some strange noises. So I doubt this is the reason for the no start.
I still think the mixture is wrong. So check out the throttle body as I described. Then you would do well to check out the egr valve by removing it and verifying that the valve head is fully in the closed position and not gummed up slightly ajar.