Intermittent starting issue.
Starter battery fuel pump ignition coil all good hundred percent.

spark fuel air is all there.

I believe it’s a sensor issue. My scan tool is not picking up anything.

I’m thinking it’s the crankshaft positioning sensor. Due to the following

Will start up sometimes with no issue.

Other times it will crank crank and crank and hesitate to start. No will not start

I had identical issues on a car of mine and that was the sensor causing the problem.

what’s your opinion, could there be another sensor I should check

 

See what's missing when it won't start. Spark, or fuel. Need to see if the fuel pump runs, and if you are getting injector pulse, if either is missing, it can point you in the right direction. Something else to check is, when it won't start, what temp does the PCM think the engine is?? The sensor hangs out in a rather unpleasant spot, and tends to get brittle, and fall apart. (as does the wiring connector to it....) an intermittent signal there would certainly give you some interesting problems.

 

CPS came to mind for me as well. When you say fuel pump is good we’re you referring to just hearing it pump or did you actually check the PSI at the rail?

 

I have fuel to the rail

 

What year is your truck? Does it actually have the pressure test port? I know advance has a pressure gauge they will rent.

 

Is there some temperature dependency ? Like it always starts in the morning but has issues after being parked for 15 min at the grocery store ?

 

​​​​​​I'm having the same problem but I live where it's 100+ in the mornings just fine no problem but during the afternoon after the engine cools down she just cranks and cranks. I've replaced everything fuel related and spark related besides new injectors

 

I'm having the same issue, if the following additional info holds true as well. Temperature has no affect. After half an hour letting it rest after an unsuccessful attempt, it will start. Temperature gauge in cab is accurate.

1998 Dakota Sport 4x4 Extended Cab MT 318 ci

 

Does it have any codes? I found the crank sensor can be effected by temp. Back when i had the pos BWD brand sensor it would start to act up after 15 min of driving. Never acted up when cool. If it's not mopar or delphi sensor i would question it. Also may want to check if the ASD relay is engaging and giving power to the positive side of the coil. It also powers the injectors and 02's. Check it when cranking.

 

Hey I know this is an old thread but I have a '95 5.9 that has a crank no-start issue at a very specific temperature. In the winter, it only does it after the engine has warmed up and cooled down to a very specific spot on the gauge. It will crank but not start unless I come back in another hour; then it starts right up.

This being the summer, it starts every morning but when I go to leave work, it won't, and the temp gauge is already up to that spot where it won't start. I've been able to get around this by pulling the doghouse and disconnecting sensors until it starts, with the check engine light on, but lately it seems to have been figuring this out and I've evolved into combinations of sensors unplugged until now where nothing will start it until the night falls.

I was told it had a "vapor lock" when I bought it but otherwise the engine runs fine and the trans still shifts great. Any ideas anyone?