Hello all,

My son has a 1990 Dakota it will crank over but will not run. I have been on web and in forums and checked everything that has been suggested and still nothing. Okay here is what is happening. Truck will crank but won't start. We have changed ASD relay twice the computer is new the pick up coil is new the ignition coil is new and still nothing. The ASD relay has 4 wires red is 12v coming from charging system, blue is 12v coming from ignition, dark green w/ black tracer goes to fuel pump, injectors and also slices into + side of ignition coil. The final wire is a blue w/ yellow tracer going to pin 51 on computer. If I put a ground to bl/ylw wire truck starts right up and runs. I have also had to replace a fusible link and have put in a inline fuse in its place. If my son drives truck this fuse will blow after a awhile. I am completely lost in finding what is wrong with this truck any help would be appreciated! Forgot to add I cannot check if there are any codes tried the key on key off and nothing on check engine light as in it does not flash or do anything.

 

What size engine? The lack of engine flash codes is very strange, it would normally mean your PCM is fried. You may also have a bad relay, as annoying as it sounds, I had to try 5 NEW relays before I was able to fix my father in laws ASD relay. Easy to test by rigging up some female disconnects onto your relay and then powering to the battery with some jumper wires while you use a multimeter to check for continuity OR for Voltage. Also, look down the line from your bl/ylw wire after the ASD and see if it is damaged or has a bad connection, also check for the infamous Y splice.

Not to sound rude, but how did you try to do the engine light read? doors should be closed and the panel should be devoid of lights except the oil pressure light maybe. (Wait 30 seconds to make sure) Then rotate to one stop before ignition and then back all the way, forward, back, forward and hold. Should always give at least a code55. To top things off your OBD1 isn't especially extravagant or intelligent. It may not even throw a code and even if it does, it could be a very generalized bordering on useless piece of information when it comes to electrical problems.

 

Sorry it is a 3.9 V6. I have tried what you suggested with checking codes. Door closed, the check engine will come on for a second then nothing. I have trace wire all the way back to computer no short. Like I stated there is 12V at the blue w/yellow wire at ASD with key in run position but if I put a ground to it truck starts up. Also the brake and anti lock brake light are on at all times. This is a 1990 no y splice or relay box the ASD, A/C relay are mounted to a steel bar on drivers fender. I have also checked a/c relay and the same thing the ASD relay does it does if I supply ground to t the clutch engages. I have checked and cleaned all grounds thinking that May be the problem but no change doing that either.

 

Ok, have you used a diagnostic tool yet? There is a diagnostic tool port under your steering column, its not OBDII its a 4 way or 6 way for a few different sensor systems. I looked into your constant lights and that could mean you have a few different problems that are making it shut off to save itself, some things that might cause this are busted solenoids and your speed sensor. There is also a lesser known RWAL flash code method, you have to ground the diagnostic port really quick and then look at the brake light. I'm not sure if any of this helps as this is from a friend with a 93 3.9 but hopefully it starts you somewhere.

 

Thereais not a Diagnostic tool port on a 1990 Dakota 3.9l. I have a 91 Dakota and ive had to pull codes off the truck numbers of times and like they said above you want to put the key in, shut the door(s), push the key to the run position but dont start it and wait for the Check Engine light to go out, then push the key back to off, then to run, then to off, then to run, then to off, then to run one last time and hold it there. It should flash codes at this point. Common first code is going to be *12 which is power loss to computer within the last 50 key cycles. The last code is always *55 which just means the test is complete. To reset the computer and remove the codes you want to remove the positive battery terminal and hold the brake pedal down for about 20seconds to drain the computers power down. This loss of power resets the stored codes. You want to reset the computer after every repair made so the computer doesnt use its memory and still think there is a problem that you just fixed. Flash examples will appear as follows: 1 flash, short pause, then 2 flashes close together is a code *12. 2 flashes close together, a short pause, then 2 flashes together is a cose *22. Hope this helps. also, a Haynes Manual is a MUST for these trucks. I bought my 91 3 months ago and that book has been a life saver! Let us know what you find out. Codes are in the Haynes manual too or you can just google codes and their meaning for your truck.Good Luck.

 

With my 1991 3.9l I had similar issues when I bought it. It ran great for about 2 weeks and it died on me while cruisin at about 40mph. I trouble shooter everything you have and replaced everything you have..mine ended up being a broken reluctor plate on the shaft of the distributor AFTER I replaced the pickup sensor. The reluctor plate is under the pickup sensor. It is a round plate with notches in it that is attached to the distributor shaft and passes threw the pickup sensor. One of the things I was told to look for in my hunt for the issue before I found the plate broken was to check the wiring harness for broken wires coming from the relay/fuse box that houses the ASD. this came from a veteran Dodge Mechanic. He said he has fixed a handful in his time that were broken wires in the harness. There are in-line fused links inside the harness(which is the dumbest thing ive ever seen) and the ones he found broken were ones that were folded over at very tight angles from the factory and over time have broken. This may not be your problem but its worth a look. I tore about 3 feet of my harness apart and I found one questionable fused link. I repaired it of course. Best of luck.

 

actually there is a diagnostic port for a reader but its located under the hood by the heater blower motor resistor.. just its OBD1 and very few scanners you buy has the connection or ability to read old skool tech.. innovo makes 2-3 but are 3-400 bucks...

the key on/off 3 times is nice and honestly i can verify it still works up to 2009 Nitro i owned and also my 2005 Liberty as it just posted the P0252 codes In place of odometer , free cheap built in code reader.... says alot about Chrysler products dont it

 

did you figure it out? im having the same issue.

 

Yes I put another computer and ASD relay in and truck fired right up and my son has not had a problem since.

 

Dam, i checked my PCM already and i checked my ASD.

No effect.

Glad your son got his truck running.