Expert: Roland Finston - 7/6/2011

Question
QUESTION: Good night i have a 1996 Ram van with a 3.9 litre engine 6 cylinders and the trouble is that a few weeks ago when i turned the key to "start" the engine started normally and suddenly it tienes off; after a few more tries i leave it there but no check engine advertisement light out.

I noticed a few days later that when i change to reverse mode (R)in turned off too, and when i was un drive mode it started to "kick forward" as a energy bridge or jump or fuel absence.

Suddenly the trouble went away and the day before yesterday started again, i think it might be the same trouble as "2,500 Ram van, no start" user.

Please help me i do bit trus anyone around my neighborhood

ANSWER: Hi Rodrigo,
Does the van have an anti-theft system? If so, it might be not disarming when you unlock the door to enter the van. Try unlocking the passenger side door to see if that clears the problem. The symptom of such a situation would be that it starts, but then dies in about 3 seconds, repeatedly.

If the van doesn't have an anti-theft system, then try using the ignition key to get any fault codes that might be stored in the memory of the engine controller. Turn the key:"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 see it start to flash, pause, flash, etc. Count the number flashes before each pause. Then repeat the process and make sure that you have an accurate set of flash counts. Tell me the counts and we'll go from there.

If that doesn't produce anything, then go to an Autozone parts store, or similar nationwide store, and have them plug in a fault code reader to the socket under the dash and see if any codes are stored. They should be 4-digit numbers. Get any such numbers and let me know. They will often do that for free.

Roland

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

QUESTION: Thanks Roland i'll try to disarm the anti theft sys; by the way when trouble showed up again, it send a code P1391 bit after a few hours of beendriven, it turned off, and know it came a new code but i couldnt take it to autozone cause it went out of energy because i left the lights on and when a frķend helped me with energy it showed up the same trouble starting and turning off immediatelly

Answer
Hi Rodrigo,
The 1391 means there is an intermittent disconnect of the camshaft or crankshaft rotational position sensor. It coult be due to many possiblilities:
intermittent loss of  8V supply voltage to sensor(s)
         signal wire
         gound wire
gap between sensor and pulsation ring or mangnet too large/damaged ring or magnet
failing sensor
loose plug on sensor
failing pcm

I don't have the manual for that engine but you basically have to inspect/shake the wire harness sort of approach until one of the sensors fails completely and that will set a specific code as to which.
Also, I wanted to suggest that you check the fluid level in the transmission. If you need more be sure to not overfill it, and be sure to use the correct type of fluid. Check the manual as to which.

Roland
PS Thanks for the rating. If you would consider doing it again I would appreciate that. This time consider giving a 'yes' where you see the question about a nomination of me to be 'volunteer of the month'. Thnak you