Hi all and thanks in advance to anyone who takes the time to reply. I've tried a few searches on this site but haven't found a good match (or solution )
to the problem I'm having. It's been a rough couple of days with a lot of walking and waiting.

I have a 99 Ram 1500 Sport 4WD AT 5.9L gas. 160,000 mi. It's a bit of a rough truck but it's always run like Hell! Feels like one of those motors that will never die no matter the abuse.....until now.

This truck has always started with one split second turn of the key without touching the gas pedal. A couple of days ago I started up normally, no issues, then drove about 20-30 minutes to the next Town. There I parked and shut down to go into a business. I came out about a half hour later and my truck would not start. Cranked over fast and hard but wouldn't catch. Since I knew I was low on fuel and my gas gauge has never worked accurately I thought maybe I ran it a bit too low so I threw a gallon in the tank from a can. Still no start. Got some ether (starting fluid), loosened the air cleaner and gave it a shot or two. Now it cranked and the ether caught but it wouldn't stay running. Few more shots, few more cranks and it's running again. Running fine like nothing happened. So I drove to work, 3 towns over, 10 miles or so, 20 minutes maybe, on the highway. No issues. End of the day I leave, hop on the highway and join the traffic parade. 15-20 minutes at 30mph and it just shuts off, like somebody pulled the plug! I throw it in neutral as I'm coasting and turn the key..it restarts. Okaaay, odd. Driving along, 10 minutes later shuts off again. Again, neutral, coast, crank, restart. Still driving. Another 10 minutes or so, few more miles and it does it again. This time it won't restart so I coast off an exit and pull over. Now all the ether and cranking does nothing so I call a buddy and wait for a flatbed. Couple hours later flatbed is dropping it in my driveway and for sh***ts & giggles i crank it. Starts right up! runs like a champ! Next day I lift the bed and replace the fuel pump assembly (also replaced the fuel pump relay up in the engine bay). I was convinced that since it was firing with the ether it was a fuel problem. Also, my fuel gauge never worked properly and with 160,000 mi I couldn't see the harm. Well I was wrong. Left my house this morning, with my 16 yr. old daughter, whom I was taking for her learners permit and guess what? Yep, About 20 minutes on the highway I feel a skip, like a hiccup, a quick on and off, but it kept going. Then a little bit of breaking up, likr the plugs were fouled. Got off the highway for the Motor Vehicle Dept., get a couple of blocks away and it shuts down, won't restart no matter what I do. Now I'm walking, about a mile and a half, with my daughter, to her permit test, and it starts pouring ( this has nothing to do with the truck symptoms but feel my pain! and embarrassment! ) So anyway, a couple of hours later, in the rain, it starts again. I head home, side roads this time, and.....20 minutes or so it shuts down. I leave it for the day, hoping someone takes it, no luck. I finally get back to it at the end of the day and it starts so I head home again. I almost made it too. It died up the street from my house. This time I had someone with me so I had them crank while I wiggled stuff (technical huh, wiggled stuff). I did pull the coil wire from the cap and checked for spark, there was none, ok, progress? I got a new coil and put it on. The truck fired right up. Got it home and let it idle in my driveway just to be sure and.....a few minutes later it shuts down and won't restart. It's dark, I'm tired and I quit.

Sorry for the novella folks but it's been a rough one. I'm already out a few hundred bucks. I'm throwing parts at it I know but I can't help it. Local garage wants $85/hr. to start diagnosing with no real idea. PITA intermittant issue. If I keep tossing parts maybe the ignition module in the distributor? Crank sensor? ECM? All this time there's been no codes or check engine light either.

Thanks for anything,

 

I think you're on track. I'd be leaning towards either the crankshaft sensor or the PCM too.

There's a test for the CPS, found here: http://troubleshootmyvehicle.com/chr...ostic-test-1#2

Basically, you put a multimeter on the sensor wire (s/b the gray wire with black tracer coming off the sensor) and turn the crank by hand- should see 5 volts cycle on and off as the sensor picks up the rotation of the crank. If you don't see steady on/off of that 5v signal, then you likely have a bad CPS.

Bad signal from the CPS= PCM doesnt know when to trigger the coil= engine dies and no spark at coil.

 

Hey, Thanks for the response..and encouragement! Went out this morning and of course it fired right up! That page link has some good info. I like the step-by-step, good clarity. Thanks for that. I did fin a TSb covering what seems to be a similar issue. Only difference is I don't seem to be getting the 'no bus' message like a lot of others tend to. There are supposedly 5 sensors that share a 5v line to the PCM and any of these can be the issue. Here's the gist of it.

Vehicles:
1998 - 1999 Dodge Durango 3.9L
2000 - 2001 Dodge Durango 4.7L
1998 - 2000 Dodge Durango 5.2L
1998 - 2001 Dodge Durango 5.9L



Symptom: Engine will not start. Gauges are inoperative. "no buS" message displayed on odometer.



System: Body/Chassis Electrical, Emissions/PCM/Fuel, Engine Electrical



Codes: N/A



Problem 1 of 6: The 5v power supply from the Powertrain Control Module (PCM) is shorted due to a shorted Crankshaft Position (CKP) Sensor.

Test & Fix: If the 5v power supply circuit is shorted to ground, the CCD bus is unable to transmit messages and the Powertrain Control Module (PCM) appears to be "dead". The PCM is not damaged when the 5v power supply gets shorted to ground, but does need to be reset by turning the key off for 10 second after the short is removed. Using a DVOM or labscope, measure the voltage on the 5v reference wire at the Throttle Position Sensor (TPS) or Manifold Absolute Pressure (MAP) sensor. If 5v is not present, unplug the Crankshaft Position (CKP) Sensor. Turn the key off for 10 seconds. Turn the key on and measure the voltage on the 5v power supply circuit. If the voltage is now 5v, replace the CKP sensor.



Problem 2 of 6: The 5v power supply from the Powertrain Control Module (PCM) is shorted due to a shorted Camshaft Position (CMP) Sensor.

Test & Fix: If the 5v power supply circuit is shorted to ground, the CCD bus is unable to transmit messages and the Powertrain Control Module (PCM) appears to be "dead". The PCM is not damaged when the 5v power supply gets shorted to ground, but does need to be reset by turning the key off for 10 second after the short is removed. Using a DVOM or labscope, measure the voltage on the 5v reference wire at the Throttle Position Sensor (TPS) or Manifold Absolute Pressure (MAP) Sensor. If 5v is not present, unplug the Camshaft Position (CMP) Sensor. Turn the key off for 10 seconds. Turn the key on and measure the voltage on the 5v power supply circuit. If the voltage is now 5v, replace the CMP sensor.



Problem 3 of 6: The 5v power supply from the Powertrain Control Module (PCM) is shorted due to a shorted Manifold Absolute Pressure (MAP) Sensor.

Test & Fix: If the 5v power supply circuit is shorted to ground, the CCD bus is unable to transmit messages and the Powertrain Control Module (PCM) appears to be "dead". The PCM is not damaged when the 5v power supply gets shorted to ground, but does need to be reset by turning the key off for 10 second after the short is removed. Using a DVOM or labscope, measure the voltage on the 5v reference wire (5v power supply) at the Throttle Position Sensor (TPS) or Manifold Absolute Pressure (MAP) Sensor. If 5v is not present, unplug the MAP sensor. Turn the key off for 10 seconds. Turn the key on and measure the voltage on the 5v power supply circuit. If the voltage is now 5v, replace the MAP sensor.



Problem 4 of 6: The 5v power supply from the Powertrain Control Module (PCM) is shorted due to a shorted Throttle Position Sensor (TPS).

Test & Fix: If the 5v power supply circuit is shorted to ground, the CCD bus is unable to transmit messages and the Powertrain Control Module (PCM) appears to be "dead". The PCM is not damaged when the 5v power supply gets shorted to ground, but does need to be reset by turning the key off for 10 second after the short is removed. Using a DVOM or labscope, measure the voltage on the 5v reference wire (5 volt power supply) at the Throttle Position Sensor (TPS) or Manifold Absolute Pressure (MAP) Sensor. If 5v is not present, unplug the TPS. Turn the key off for 10 seconds. Turn the key on and measure the voltage on the 5v power supply circuit. If the voltage is now 5v, replace the TPS.

Now that it's in my driveway instead of on the side of the road I may start troubleshooting for real. Although that crank sensor as well as the cam sensor (aka- ignition module in the distributor) are really difficult to get to! Are we really supposed to be able to access those! I'm pretty flexible but I feel like I need eyes on stalks and fingers like ET to get back there! Part of me wants to throw in the towel and drop it at a shop but....I hate to pay people to do what I can do!

 

If you are getting a no-start, but, not getting the no-bus message, chances are good that either the cam, or crank sensor is bad. Won't necessarily set a code, or give the no-bus message.

 

+1.

I meant cam sensor, said PCM.

Oops!

 

Thanks guys. My thoughts are leaning towards crank or cam sensor also. I just climbed over the motor and jammed my arms down the back trying to get to the crank sensor....wow..I'm not Gumby! You have to do that one totally by feel huh. I can't even tell if its' a 2-piece assembly (is that a 2 bolt, L-shaped bracket holding the sensor in? ) What's the rubber? I feel a grommet that the 3-wire disappears into.

 

Nevermind regarding the crank sensor...all I had to do was look at a picture of the part, (which is right in the how-to link from you Twmays, thank you). Yes, that's exactly what I feel. So now I decide whether to get it to die and do the diagnostics or just change those two sensors while I'm all contorted back there anyway. I read one guys post somewhere basically saying that with higher miles and one sensor gone the rest are of the same age and wear so why not do them since they are not that expensive. Preventitive? Will continue to post results (or new issues).

Thanks,

 

Warm it up till it quits, then see if you are getting spark. If not, replace the crank sensor. if you are, replace the cam sensor. Easy. (just wait for the motor to cool some before crawling in there again. Gets a bit warm.)

 

HeyYou (*chuckle* I like that Tag), I actually managed to check spark yesterday during one of the die and wait sessions I had with the truck. As soon as it died I popped the coil wire from the cap and checked...no spark from the coil. So what's the logic...no spark from coil it's a bad crank sensor. Actually let me make sure I understand. Where would you check spark at? Pull a plug wire for spark from dist. or pull coil wire for spark from coil? I pulled coil wire..no spark.

I just picked up both crank and cam sensors so I'll probably just change them both. I know it won't help anyone else diagnostically but I'd rather do them both now while I'm wedged in there and yes, the engine is cold! Nothing like laying your forearms down on those nice hot rocker covers!

I'm a fairly decent wrench and I've been working on cars since before I could legally drive, ( I won't say how long ago that was but I can adjust points, hint, hint! ) but sometimes all these sensors just make me feel like an old dog!


Thanks for the help guys,

 

You can check for spark anywhere that is convenient for you. If it isn't coming out of the coil, you aren't going to find it anywhere else either.

Just to verify the crank sensor is the problem though, try manually firing the coil when it isn't sparking. Just splice a wire into the ground side of the coil circuit. Grounding the coil, then removing the ground, will fire it. (possible your coil is bad, and not the sensor, though, the sensor is the more common failure.)