Have a '93 Ram B250 (5.2 L) Van that cranks, but not starting and No Check Engine Light (MIL).

What's strange is that the Check Engine Light is not illuminating at all... not even when the key is put to the "on" position, so can't really verify that there's no codes being set. These problems both appeared at the same time, as I always wait for the Check Engine Light to go "OFF" before putting the key into the "Start" position (always starts faster, as the fuel system is primed). Now theCheck Engine Light doesn'teven come on and engine just cranks, but I DO hear the fuel pump relay click as soon as I turn key to "on".

This just happened out-of-the-blue, with no forewarning...

I have not confirmed spark or fuel pressure yet. Repairs I have done over the last few years include Crankshaft Position Sensor and Fuel Pump/Sending Unit...

Besides a burned-out bulb for the Check Engine Light (which would be a HUGE coincidence that it happened just as the no-start condition appeared), what else would cause this bulb NOT to illuminate?

Thanks for any input!!

 

More than likely the fuse that feeds the PCM blew, the ASD relay is bad, or the PCM itself is fried.

 

Due to limited sunlight, then a DOWNPOUR, was not able to do too much diagnosing... I believe I ruled-out the ASD relay (was able to supply BAT+ voltage to the wire @ term 87, then swapped the ASD and Fuel Pump relay just to see it it would fire up at all), but still nothing.

The Chilton wiring diagrams (yeah, I know...CHILTON!) aren't too detailed, but there seems to be a "Power Distribution Center" (PDC)with MAXI fuses in it... what are MAXI fuses and where might this PDC be located? It seems to be getting powered by the 6 ga. black wire that "T's" off the POS+ Battery post, but I cannot locate anything w/ fuses in it prior to reaching the PCM on the firewall... Again, it got dark and started raining HARD, but nothing seemed obvious as to where this PDC is located, and the only fuses I could locate where the dozen or so under the glove box door (which just didn't seem like enough???)

I'll get a better look in the sunlight tomorrow... just trying to rule-out the PCM before throwing away $200+

Thanks!!!

 

On my 97 Ram B2500 the PDC is located on top of the radiator support. It is the same box that the relays are in. I will see if I have any info on yours and if there is a difference.

 

On the PDC I have not found where on yours it is. Might look for a black plastic box on or near the radiator to some where near the battery.

Now I did find that you can check on the PCM pin #3 (A14 Red) wire for positive voltage. That should tell you if the PCM is getting power or not.

Might try swappng the ASD relay with the Auto Shutoff Relay and see what that does. It appears that Auto Shut Off Relay has power going to the PCM.

 

Um, the "Auto Shut Off Relay" is the ASD (Auto Shut Down) relay.

 

Learn something new today, thanks. Only had my van for 4 days now so I am still learning about them.

 

Learning something newis nature's way of letting us know we haven't diedyet!

 

*Update*

OK, it's looking more and more like the PCM... here's what I've done/checked:

(First of all, it may NOT have been the fuel pump relay I was hearing when the key put to "on")

During CRANKING - No Spark

Key "ON" - NO sign of Fuel Pump kicking in

Swapped ASD relay and Fuel Pump relay - no changes

Applied 12V to "87" terminal of Fuel Pump Relay - Fuel Pump DOES come on

Applied 12V to "87" terminal of ASD relay while CRANKING - no changes

Tested for power @ #3 terminal of PCM - 12.53V (so fuse must be good)


It seems as though I've ruled-out everything BUT the PCM, but just in case anyone still has a suggestion... please chime in (I have ordered the PCM, but can still get out of it before taking it home [sm=confused06.gif])

THANKS SO MUCH for all the suggestions so far... I've definitely learned quite a bit from this already!!!

 

* Update 2*

Bit the bullet and purchased the PCM, but all OK since it WAS the problem.

Thanks again for all the input