troubleshooting voltage issue
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troubleshooting voltage issue
I had just left the house the other morning and about 2 blocks down the road the truck just died. It turns over just fine but never starts all the way. I had no spark at the coil so I checked the incoming leads. NO 12volts at the coil with ignition in start pos. 
so I jumped the ASD relay and tried again. Still nothing. I tested the pickup coil per recommendation in my manual by jumping the 2nd and 3rd pin receiving holes on the distributor mains plug. I guess I am supposed to get spark when the jumper is toggled open/closed if its working right. I think it is as it actuates the fuel sending unit and sprays fuel into the TB every time, so I know its doing that part of its job, despite the lack of spark. I am assuming that no spark from the coil is still just a result of no volts present.
Continuing on... I removed all the protective wiremolding and started looking for rotten connections, I have yet to find any. All the splices I found look good (and test ok as well). I did find that the neg signal from the smec is not sending, but I don't know where to check after that. I replaced wire going from the smec 14 pin plug to the neg side of the coil just incase it had some weird resistance building under load or something ??? (grasping, but couldn't hurt). Bottom line is, I am running out of time and eventually money as I will miss work tomorrow because of this. I'm bummed, I love my truck. I think it may be the smec itself, but I don't know how to check that all that well. I can't find any decent breakdowns/diagrams for that as all I've got (or ever needed) was my haynes manual.
Any thoughts, ideas, or further experience on this one? remember, I have checked the common wiring corrosion probs thus far and I forgot to mention that I have proper neg 12vdc to all black / blackwhite wires on the smec plugs.
88 dakota 3.9L
Thanks,
so I jumped the ASD relay and tried again. Still nothing. I tested the pickup coil per recommendation in my manual by jumping the 2nd and 3rd pin receiving holes on the distributor mains plug. I guess I am supposed to get spark when the jumper is toggled open/closed if its working right. I think it is as it actuates the fuel sending unit and sprays fuel into the TB every time, so I know its doing that part of its job, despite the lack of spark. I am assuming that no spark from the coil is still just a result of no volts present. Continuing on... I removed all the protective wiremolding and started looking for rotten connections, I have yet to find any. All the splices I found look good (and test ok as well). I did find that the neg signal from the smec is not sending, but I don't know where to check after that. I replaced wire going from the smec 14 pin plug to the neg side of the coil just incase it had some weird resistance building under load or something ??? (grasping, but couldn't hurt). Bottom line is, I am running out of time and eventually money as I will miss work tomorrow because of this. I'm bummed, I love my truck. I think it may be the smec itself, but I don't know how to check that all that well. I can't find any decent breakdowns/diagrams for that as all I've got (or ever needed) was my haynes manual.
Any thoughts, ideas, or further experience on this one? remember, I have checked the common wiring corrosion probs thus far and I forgot to mention that I have proper neg 12vdc to all black / blackwhite wires on the smec plugs.
88 dakota 3.9L
Thanks,
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You just made my morning! I will have to look for them later today. I'll repost if I make any headway on it. Thanks man.
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Hey I found the diagram links you posted, specifically the one for a 1990 but all the links say "file not found". Can you help me still? Other links maybe?
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From: NM