Okay folks I don't have any hair left.
1990 Dakota 3.9 Automatic 4X4

Problem: Running fine, shut off, no restart since.

Troubleshooting: All fuses Good. No power at + side of coil. ASD and Fuel Pump are the same relay. Followed troubleshooting of ASD relay in FAQ> Constant Power pin 30, Ignition power pin 86. Relay does power up momentarily when key is first turned to ignition and at the same time there is momentary power at coil. During cranking there is still power to pins 30 and 86. However, during cranking there is no power to the coil. Removed relay and jumper power from pin 30 to pin 87, fuel pump running, power to coil but still no start. For the heck of it, changed ECM out with a known good one, still no start.

Ideas?

Jim

 

Replace the coil. Not because it makes sense, but because my experience tells me it's a common failure (mine just died again yesterday, cruising down the freeway). Starting today, I'm going to carry a spare, lol.

A cheap one is only like $29 and it only takes a couple of minutes to replace (assuming yours is like mine). If the cheap one fixes the problem, buy a good one and keep that as a spare (my plan).

 

Thank you. I doubt it is the coil, but to be sure I did an ohms check. Primary 1.8 ohms and secondary 7.8 KOhms.

Any other ideas?

Jim

 

Just so we are clear you say you jumpered the relay, and you get power to the fuel pump and coil, are you seeing spark then and it still isnt starting, or are you just getting power to the coil and still not seeing spark? Just want to make sure we are on the same page here.

 

maybe the hall effect pick-up gizmo in the dizzy?

 

Initial Key on, power to coil and fuel pump for 2 seconds.

Cranking, no power to coil or pump (relay not energized)

Jump relay, fuel pump runs, power to coil, crank no spark and no injector fire.

Can't seem to locate where the relay gnd signal comes from during cranking. Wiring diagram https://docs.google.com/file/d/0BzA-...rive_web&pli=1 shows the relay but not where the ground comes from during crank.

Computer has been changed with a known good one.

Jim

 

Have you checked the splice under the fuse box? Apparently it's a common problem..

 

The 1990 does not have a master fuse box under the hood. I did check the wire bundle on the left fender well and it is fine.

 

Just to let you all know in case someone else has the same issue.

It turned out to be the hall effect pickup. If the ECM does not see a signal from the distirbutor, it will not set a ground to the combination ASD/Fuel pump relay.

So kahanabob was correct.

 

every once in a while i luck out, in this case i had a 90 and had hall effect issues......