I was driving yesterday. parkedit for the night.(95 Dakota pick upwith 5.2 V8). came out to go to work the next morning. it would turn over but not start. what in the world could have happened. I have heard that the crank sensor can do this. and if so would it disable the fuel pump and injectors???

Any help would be most welcome. Thank You

 

if your crank sensor was bad it should throw a check engine light. cycle the ignition three times and it will display any codes listed. Otherwise start with the basics, spark, air, fuel

 

Had the same prob with my '95 had to replace the PCM and worked fine after... Don't know if that is your problem, but just throwing that out there

 

mine did this couple months ago test the coil and see if it has right voltage going through it.

 

I saw in the faqs that there is a common problem with a splice under pcm in the supply voltage to shut down relay and fuel pump relay. The relays work. i can hear them clicking. anyone know is the faq ment that the relays were not swithing the 12 volts across the contacts when they activate ??? looking at a schematic that they do switch 12 volts over to ecm or main computer module. would the absent 12 votls from the auto shut down and fuel relays cause ecm to not allow fuel and spark.

Thanks for the replies.

 

in earlier post i meant it said bad splice under PDC or power dist center directly under auto shut down relay and fuel pump relay.

 

Bingo . I founfd the problem. I had lost power to the PCM. I'm pretty sure it was the bad splice mentioned in FAQ's, thats under the PDC.I ran my own constant power to it and of I go.

Thanks for the replies Guys and Gals.

 

[hr]87 dakota 3.9 v6 shut down while driving getting fuel but no fire changed coil, ignition module but still no fire. is there any other items that may be causing this problem?

 

try the wires my dad had this happen to his 3.9 parts hauler and he sold it to his brother who changed the wires and it started and ran fine

 

Are we talking no fire at the plugs, or none from the coil? If you have fire going into thedistributor but it doesn't get to the plugs, the rotor has burned through to the shaft (seen it many times) or just plain broken (or the cap is missing the rotor button). No fire from the coil itself, check to make sure the coil has power and signal (you'll need a scope to check for signal).

-If it has power but no signal, pop the dist. cap and make sure it is turning. I've seen the OP drive bushing go bad and shred the gear on 3.9's, which means dist no turny. If the distributor is turning, scope the crank angle sensor. If it checks OK, make sure that signal is getting to the SCC. If it is, then check the output for the coil signal wire. If it has output, then there is an open between theSCC and coil negative. If there is no output from the SCC, then theSCC is junk.

-If there is no power to the coil, then make sure the SCC has power. If the SCC has power,check power out to coil. If SCC is sending power to the coil, then there is an open between the SCC and the coil positive. If not, SCC is junk.