Intermittent "no crank"

[Terry O.]

I have a 1995 Ram Van 318/Auto, 75K original miles with a weird Intermittent "no crank" issue.

Van usually cranks & starts normally. But I will get an occasional "no crank" usually when temperature is below 50 degrees.

Symptoms are as follows:
Dash lights (check engine, etc.) come on when key is turned to "ON" but will not crank when key is turned to "START" position.

Outboard push button switch between batt + terminal & solenoid "S" terminal will crank the starter. This is my backup starting technique.

Battery shows 12.75V.
Starter relay tests OK per dodge manual test
New Neutral safety switch on tranny tests OK per dodge manual.
Battery terminals are clean & tight.


As temp falls below about 50 degrees problem gets progressively worse.

What am I dealing with?

Is the Starter relay a temp sensitive device & showing the first signs of failure?

Any help is much appreciated.

 

[jf5.9]

Have you checked the Crankcase Position Sensor?

 

[Terry O.]

I did a temp test on the starter relay. I removed it & put in the freezer for an hour or so to simulate cold conditions.

The resistance test between terminal 85 & 86 read 63 ohms when I took it out of the freezer. the manual sez it should be 75 ohms (it reads 73 ohms when warm). I

I thought I was on to something. However when I re-installed it, the van started as normal so I'm still perplexed.

 

[BradTN]

Your problem does seem like a temperature related, intermittent relay or switch issue, but if you haven't checked the starter solenoid contacts and plunger yet, it may be a good idea. You have low miles on the truck, but I would want to be sure that the contacts were good before testing anything else... if it were me. The Starter comes off easy enough, and you can clean the contacts or replace. let us know what it was when you solve it.