diggerdan11 Posted August 19, 2007 Report Share Posted August 19, 2007 So i just got a Nelson PCM and a installed it today. i was all excited but the car would not start so i tried to crank it over and over again and i stoped then i gave it a little gas and it eventualy started..........So i was all happy, but i turned off my engine and only had it off for less then five min and it would not start again.........I then unpluged the batterie and removed the PCM and the hooked it back up again, but it still would not start. i kept trying and trying to start it agin and it fianlly did and i drove it about 10 miles or so and i was very inpressed. well i got back home and turned it off and about a half an hour later it would not start again Does anyone have any idea why it will not start sometimes and it will other times Quote Link to comment Share on other sites More sharing options...
stevebbb Posted August 19, 2007 Report Share Posted August 19, 2007 I''m not sure if this will fix your problem, but it's pretty common to have to do a relearn procedure when installing a new PCM. I did a search and came up with this from MR. P. Give it a try and let us know. 1) Try to start the truck(it should start but die right away)leave the key in the on position for atleast 11 minutes (the security light will remain on for 8-10 of those minutes).... 2) AFTER the 11 minutes the light should have gone out (if not thats ok), now turn the key to the off position for about 30 seconds. Now try to start the truck again and it should start and die right away, Leave key in the on position. 3) Once again w/o turning the key to the off position, Let the truck sit for 11 minutes, after 11 minutes then turn the key to the off position for 30 seconds. 4) Retry again to start truck, it will die again and follow same thing as before for the last time. After the third time it should start right up. And then you can go test out the new beast P.S. Make sure to turn headlights off, radio, subs, amps and any other accessories....Since this process takes 30+ minutes your battery may die if you are blasting your radio while trying to be patient Goo luck! Quote Link to comment Share on other sites More sharing options...
detjoe Posted August 19, 2007 Report Share Posted August 19, 2007 I have read this before too, but what exactly does this procedure do?? what gets relearned?? is this a crank relearn?? any GM people validate this procedure??? kind of a lot of work for nothing??? Quote Link to comment Share on other sites More sharing options...
stevebbb Posted August 19, 2007 Report Share Posted August 19, 2007 When I installed my new pcm, I had to do the relearn. It wouldn't start until I did. Quote Link to comment Share on other sites More sharing options...
brobradh77 Posted August 19, 2007 Report Share Posted August 19, 2007 (edited) I have read this before too, but what exactly does this procedure do?? what gets relearned?? is this a crank relearn?? any GM people validate this procedure??? kind of a lot of work for nothing??? The way I understand it is your PCM is VIN specific and when you reflash one or a new one for the first time the truck has to re-learn the VIN. BUT this only happens on the first tune. I have 2 PCMs so my truck doesnt ever sit and I only had to do a relearn procedure once. if you reuse your original PCM I dont know if you have to use the relearn procedure or not because i bought an extra one and it was used with my first tune and not my original. Edited August 19, 2007 by brobradh77 (see edit history) Quote Link to comment Share on other sites More sharing options...
diggerdan11 Posted August 19, 2007 Author Report Share Posted August 19, 2007 i tried that whole relearn thing last night and it still did not work, i wonder if it might work if i try removing the PCM and instaling it again Quote Link to comment Share on other sites More sharing options...
brobradh77 Posted August 19, 2007 Report Share Posted August 19, 2007 i tried that whole relearn thing last night and it still did not work, i wonder if it might work if i try removing the PCM and instaling it again when installing the PCM did you disconnect the neg. cable from the battery? Some forget and thats important and could be why the relearn isnt working so if you didnt try that and re install it. Quote Link to comment Share on other sites More sharing options...
fox_forma Posted August 19, 2007 Report Share Posted August 19, 2007 make sure you didnt tighten down the bolts on the PCM harness way to much. I had issues with that once for some odd reason. Quote Link to comment Share on other sites More sharing options...
diggerdan11 Posted August 22, 2007 Author Report Share Posted August 22, 2007 An update just in case you guys were wondering. I called Nelson performance and they told me it was a bad PCM or something happened during the tuning process. They sent me a new one and i put it in and it fired right up Quote Link to comment Share on other sites More sharing options...
Badkarma Posted August 23, 2007 Report Share Posted August 23, 2007 Glad to see you got things worked out Quote Link to comment Share on other sites More sharing options...
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