I have a '98 Dakota 3.9 two wheel drive automatic standard cab 300,000 miles. I have a question concerning the computer. I have intermittent sudden shut down and most times it will restart with no problems. When it does not restart immediately it will restart after waiting a few hours(cool down). I have replaced the crank sensor. Could this be a coil? My first question is has anyone experienced this? Has anyone used one of the computer re-manufacturers? My last question is can a salvage computer work as long as the options are the same, can a computer be reset without going to a dealer. Thanks for your time and help.
'98 3.9 computer.
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When you have the no start, check for grounding at the injectors. A cheap test light can be used. Find the injector plug and probe with switch on. The one that stays lit is the power. Go to other wire and have someone crank it over. This is the ground side, which the pcm controls.you should se the light flash.if not your pcm is not firing the injectors. Doesn't mean bad pcm tho. Check ASD relay. Swap another relay and see if problem goes away. Check voltage to sensors, TPS, IAC, ect. Should see 5v on a wire of each sensor. This will verify comp is providing reference voltage. Coil can do it also, but I believe the problem is elsewhere. Check the basics...when it no starts. Do you have spark? Do you have injector pulse? Find out what's missing and it'll lead you to the problem
Thanks for your help.
Thanks for your help. The issue is most of the time it starts imminently up with all systems working properly with everything getting power. I think changing the coil might be next. Now what about the computer, can a salvage computer be used without a dealer reset. I hope I don't need to replace the (pcm). Anyone used any of the send your pcm in and we will repair and reset your computer guys that are on line. I hate this "try and part one at a time" stuff. I tried Rock Auto and can't find a pcm,computer listing. Thanks for your suggestions and help.
I had a similar issue; however mine is a '03 with a 5.9.
So keeping that in mind, when mine was in the "crank but not starting mode", I was not getting voltage from the coil when cranking. While this issue was intermittent, I changed a bunch of parts; however, this issue devolved from being intermittent to being a permanent no start condition.
(Which is easier to troubleshoot.)
Keeping that in mind, & shortening the rest of my story, the rest of my troubleshooting ended in not getting voltage at the trigger wire (when cranking) from the PCM to the coil (which on mine is a black wire w/ white stripe), as evidenced by back probing trigger wire with a test light & not observing it flashing (when cranking).
I realize that your issue is resolving itself almost immediately, so that makes it harder to troubleshoot.
However, if your issue devolves as mine did, if you get no voltage from your trigger wire to coil, the troubleshooting tree I followed drove me next to the ASD relay (which I had already swapped) & then to the PCM.
I am going to plug SIA Electronics in (I believe) Tilden Il., simply because they solved my problem. I contacted them & sent them my PCM. I cannot remember what the bill was, but I remember it being under $150.00. They told me they replaced the "coil transistor" & "resoldered a loose pin". They do have a fee for checking & finding no defects & shipping back, but I cannot remember how much it is, but it is probably on their web site.
So I'm just throwing that out there for you in case that's what your issue turns out to be, as they solved mine.
I tend to doubt your problem is your coil. My admittedly limited experience has been that coils either work or they don't. But I would think that you could get a coil from RockAuto.com pretty affordably if you want to do that as a check, & even if it doesn't work, at least you will always have a spare coil. (That's the rational I am holding on to for my extra relays, cam pos sensor, & crank pos sensor I now own).
I hope you post the resolution to your issue for the future reference to us all.
Good luck!
So keeping that in mind, when mine was in the "crank but not starting mode", I was not getting voltage from the coil when cranking. While this issue was intermittent, I changed a bunch of parts; however, this issue devolved from being intermittent to being a permanent no start condition.
(Which is easier to troubleshoot.)
Keeping that in mind, & shortening the rest of my story, the rest of my troubleshooting ended in not getting voltage at the trigger wire (when cranking) from the PCM to the coil (which on mine is a black wire w/ white stripe), as evidenced by back probing trigger wire with a test light & not observing it flashing (when cranking).
I realize that your issue is resolving itself almost immediately, so that makes it harder to troubleshoot.
However, if your issue devolves as mine did, if you get no voltage from your trigger wire to coil, the troubleshooting tree I followed drove me next to the ASD relay (which I had already swapped) & then to the PCM.
I am going to plug SIA Electronics in (I believe) Tilden Il., simply because they solved my problem. I contacted them & sent them my PCM. I cannot remember what the bill was, but I remember it being under $150.00. They told me they replaced the "coil transistor" & "resoldered a loose pin". They do have a fee for checking & finding no defects & shipping back, but I cannot remember how much it is, but it is probably on their web site.
So I'm just throwing that out there for you in case that's what your issue turns out to be, as they solved mine.
I tend to doubt your problem is your coil. My admittedly limited experience has been that coils either work or they don't. But I would think that you could get a coil from RockAuto.com pretty affordably if you want to do that as a check, & even if it doesn't work, at least you will always have a spare coil. (That's the rational I am holding on to for my extra relays, cam pos sensor, & crank pos sensor I now own).
I hope you post the resolution to your issue for the future reference to us all.
Good luck!
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Very good point Jaycee. Loose or dirty grounds can cause all sorts of gremlins. As the PCM grounds everything it switches on and off a good ground is imperative.
It could be almost ANY ground on the truck; but usually not only where the computer grounds to the chassis, but also where the negative cable grounds to the block and/or the chassis, or any or all of the above!
RwP
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