2001 Dodge Dakota (4.7L) won't start after running 10-20 minutes

75stingray

Newbie
Joined
Mar 27, 2021
Messages
1
Points
1
Make
Dodge
Model
Dakota
Year
2001
Miles
100,000
Engine
4.7
My 2001 Dodge Dakota (100k miles, 4.7 V8) often times won't start back up after driving for 10-20 minutes, turning the truck off, and attempting to restart a few minutes later. It just cranks but won't fire. Each time (6 times now over the past 6 months) it has finally started after sitting for 30-60 minutes. The check engine light is on and the primary code showed a bad crankshaft sensor which I paid a repair shop $140 to replace yesterday. Last night I drove 10 minutes to town, went inside a store, came back out 15 minutes later and it wouldn't start. I sat there 30 minutes and it finally cranked up. Truck runs smooth when running. What else can I have the repair shop check that won't break the bank? Thanks for your help...newbie and first post so hope I've included the pertinent info. Mike
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
7,109
Points
63
Your post is fine. An intermittent like this can be very hard to "catch in the act", so your least expensive course of action is to do some DIY trouble-shooting when the problem pops up. Are you willing to go that route? Otherwise, it may be necessary to throw a lot of parts at it or leave it with a shop long enough for them to drive it until the problem happens again.

There are countless things to check when hit with a "crank but no fire" event, but let's get back to the CKP sensor... the code points to a circuit, not just the sensor. That CKP circuit usually includes the sensor, wiring/connectors, PCM, ICM (if separate), and the triggering wheel. The wheel is not often a problem, if crank mounted, but distributor wheels are a bit more fussy. Also, don't assume the replacement CKP sensor was good. Bad parts occasionally get manufactured, even with quality vendors. Worse yet is our present culture of "anything is returnable for refund". Who knows if that sensor was dropped or misused and ruined, then returned to stock?
 

Mobile Dan

wrench
Joined
Mar 1, 2002
Messages
3,763
Points
48
Location
Kentucky
Buy or borrow a scanner that will show live data. Keep it in your truck. When the problem occurs, crank the engine while viewing ENGINE RPM. Should see about 250 rpm. If it is 0 or a very low number, the crank speed sensing system has a problem. Could be the sensor or numerous other things as Bill has mentioned. If you have a good crank speed signal, the cam sensor may be the problem, some engines need both cam and crank signals to start.
Another thing that can happen is a sensor that "shorts out when hot". This problem can disable other sensors that share the same circuit (usually a 5v or 8v power feed from the PCM).
 

grcauto

Hero Member
Joined
May 29, 2014
Messages
784
Points
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Forgot that these will continue to run with a failed cam signal but will not start without a good cam signal.
 
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