Hi, i am having a huge issue with a truck my father in law just bought. It is a 1994 Dakota with a 3.9l auto, the truck has a NO START condition. I noticed that i have 8 volts at the Crank and camshaft sensors, but No 5 volts on any 5v wire in the system.

I unplugged every 5v sensor on the engine hoping that the 5v reference would return to the purple/white wire but it has NOT. the ASD relay clicks when power is sensed then 2 seconds later clicks again and kills the power. i have tried everything i can think of and with no luck the truck sits in my yard.

I have 12v at the ASD relay
I have ignition hot 12v at the ASD
I have 8V at the Cam and crank sensor
I have good grounds at the Cam and Crank wiring
New crank sensor
New wire splice under relay box as well

I cut the purple/white wire about 6 in frm the pcm to see if the 5v would come back and it did not, so i though the PCM was bad and bought a used one, the used PCM i though was going to help but all it has done is confuse me. The check engine light with the original PCM would sometimes work and sometime not work, also a high pitched noise could be heard at times with the original PCm. When i installed the used PCM the noise went away, and the check engine light now works. I was able to pull 3 codes from it. Code 12,24,55 well i was only worried about the code 24 TPS sensor code since it is related to the 5v reference.

New TPS did not help anything, So now maybe a master dodge tech can help me out, i have 10yrs experience working on cars and this truck has me beat.

If i back probe the coil wire Green/org and i take the neg cable off and then touch the battery i get 12v until the ASD relay cuts off, so i jumped power to it and still wont start.

Maybe im looking at the wrong diag for this problem, maybe the used pcm is no good? i don't know im lost at this point and thought maybe someone has had this problem before and can help me learn something new and get my father in laws truck going again for him.

the truck ran fine then just shut off while driving and has not started since.
i checked every relay,fuse wire in the entire harness. i replaced all the splices in the harness, He replaced the crank sensor and the Distributor then put the orginal distributor back in when that did nothing. It is in the correct place i checked it for him. Maybe there is a flow test i have not seen or something please help thanks Tom

 

no need to replace distributor no advance weights to stick or advance can to rupture. I read thru quick; did the dist pick up get replaced at some point?
I just had a goofy issue on mine and thats what it was;
also be careful on the crank sensor; the orig style ones were thick plastic most current parts store replacements have a metal bracket that is much thinner; meaning the original bolts will bottom out way before the crank sensor is tight to the block.
I just had to replace the crank sensor on my 93 and ran into that; (actually did same mistake on my 94 some months back) upon pulling tranny I pulled sensor to protect it from damage (being slammed by trans as I slid it back under truck) Somehow (don't ask how; I wish I knew the answer) I put the crank sensor back in started the engine and within a minute it died; the crank sensor (OEM plastic style) busted and I had to replace. I wound up running 5/16" nuts up onto the crank sensor bolts and then using a flat washer under each, to get replacement style sensor to actually tighten up before the bolts bottomed....

 

one more Q for you; whereabouts are you located; there may be a member of the site in your area that can help out, sometimes its easier to see the problem than to try and explain it

 

On the 2000 an older jeep grand cherokees they had a problem with the asd relay also. The failure was almost always inside the pdm (power distribution module ). Its worth a shot to maybe find a good used pdm and see if it restores the 5 volt supply.

 

Im located in Pinellas Park Florida

I dont think a 94 dakota has a PDM, Maybe a PDC (Power Distribution Center) where the ASD relay is located.

Just dont make any sence to me, the original PCM has no 5v when everything is un plugged, same as the used unit i have? Ever no matter what i do or try the Purple and white wire never shows any value on the MM. would this not mean the new (used) PCM is no good?

 

ohhh crap it sounds like the hair puller I had on my 97 Cherokee a year ago...

 

ok new info, when i disconnect the negitive batt cable. Then i touch it to the battery, for a split second i get 12v to the coil. The asd relay and fuel pump both click then click again and its gone.

Is there any 94 manuals i can down load cause all data and mitchel both suck for this truck. Help me please im running out of ideas. i also tried to hot wire the coil and i get 12v, can i jump the fuel pump and should the truck fire up or will this hurt the pcm?

 

turns over but no start. I have been circling the web trying to find fix. customer parked truck in garage. went to start it a week later and no go. repaired a badly corroded wire under fuse panel. no go. checked pcm voltages, have proper voltages for 6v, 8v, 12v at pin locations where needed. have changed fuel pump. fuel pressures good. checked fuel pump relay (replaced), check ASD relay(replaced). same idea as other posters, where I have 12v going to coil but only for a second or two. then cuts out. I assume something to do with ASD. also found on web that it could be torque convertor solenoid. unplugged all harnesses going to transmission. no soap. still no fire. when you turn on ignition, I hear certain relays and solenoids clicking like normal, but still no fire. any other ideas??