high voltage and evap codes. stalling no key response chirstmas tree dash

[MatthewGoff]

So im driving to work yesterday and my 4.7 says check gauges and the voltage gauge is pegged out high. i shut it off and cut it back on its fine. it throws codes for evap and high output voltage. i go to drive home and it stalls out while driving and stopping. doesnt matter which. while driving the engine shuts down without warning except for a ding that goes off, and all the gauges stay like the engine is still operating, the radio lights A/C still going etc... then they all drop out and dings some more, and every light on the dash lights up like i just pulled the ecm fuse to clear codes. put it in neutral and turn the key it does nothing, put it in park it does nothing.

I changed the alternator and the battery last night, still high voltage, still stalling out, no key response, still putting out over 14 volts. it will crank and run but not for long just sitting at idle, it shuts off on its own and all the accessories still work when it does so. turn the key while it still has everything on and it does nothing for a few minutes.

where should i look? ECM? NSS? Ignition switch?

BTW: I changed my fuel pump about months ago and have had no problems before or after except for my upper rad hose blew up and spewed antifreeze all over the batter and PCM but didnt get it. i did notice however that a wiring harnes right above the batter that has a screw going through the plug still had some antifreeze puddled up, not much but still has me curious.

If there are any electrical guru's out there that may be able to point me in the right direction it would be greatly appreciated. I'm driving my Cherokee now so at least i have a spare vehicle to drive while i sort this out.

Thanks, -Matthew

 

[TERRY G ABNEY]

You could check and see if you have EVAP canister purge valve ,,this might cause some of the issues and perhaps the stalling,, unsure if it can cause your voltage spike but perhaps faulty wiring to the valve ? Worth checking

 

[MatthewGoff]

You could check and see if you have EVAP canister purge valve ,,this might cause some of the issues and perhaps the stalling,, unsure if it can cause your voltage spike but perhaps faulty wiring to the valve ? Worth checking

SO i went on ebay and found a junkyard computer from OEMPARTSEXPRESS. that was friday night, computer made it in yesterday afternoon, i had already taken the other ECM out to check out the internals and in the process totally *****'d it.

BUT, the replacement ECM seems to have solved the problem, running driving no stall for the past day. only thing that is bugging me about it is that the ABS warning is constantly blinking. Brakes all the way around up up to date on maintenance, brake fluid reservoir is full and intact. So i'm not gonna sweat it one bit. got my truck going for 100 bucks plus the 140 for the alternator i did not need.

all in all the original ECM was at the end of its life expectancy.

If you do go the route of ever having to change your ECM the following i stated above in the OP could lead you to a faulty ECM. Also, if you opt out like i did for a junkyard swap you have to have the same number code that is on the casing of the ECM, for example mine was 737AC.

 

[TERRY G ABNEY]

glad you got it going, could be a speed sensor that has failed. You need the proper diagnostic trouble shooting chart and a volt/ohm meter to trouble shoot where the problem lay or it may even it might be to a bad ground to your ECM since you just replaced it ,,, I replaced my ecm and had it flashed with my vin and only cost $157 and have had no issues,,says they give lifetime warranty but it fixed the issues that were going on at the time with my truck

 

[MatthewGoff]

well the truck didnt make it hours... left work and was running errands and the truck chimed and shut off. did it 7 times in ten minutes, stall no key response. junkyard computer is throwing a code for power steering pressure switch and the ABS light is on. just for good measure and process of elimination i took the bed off and exchanged my fuel pump that was under warranty. started the truck and it idled for about fifteen minutes then shut off on its own. im not sure what could be locking out the ignition from turning the starter over but im doing all that i can to not take it to the dealership.