jumped backwards wont stay running
i got the alternater tested just now and ht tested good 5 times we tested in a row.. so now what could it be.. i am going to work on ht more tonight and keep you all update. also to rule out my wire harness which colt on the alternator Hr the charge output as i would like to run a new wire from that directly to my battery and see if my gathered stuff works and charges the batteries so i can know it is in my wiring a short and not a fried computer. i think i run it from the big bolt right? or the 2 small ones on the back
SO, while some simply put a new ALT in and it fires right up, on some models, it ends up killing the PCM thus requiring a new one. Dodge is like this by the way.
So, what you accidentally had happen was, + voltage was sent to ground via the other battery due to miswired terminals. This is very damaging to any electronic system that uses / ties the switching scheme to ground. This sends a huge voltage spike into the components through their respective ground leg thus frying them instantly in most cases.
I would say that if it's a Dodge- there's a really good chance that the PCM was damaged.
The reason you don't see any blown fuses is because the voltage current did not exceed their rating. They only pop under dead short conditions or, if the load exceeds the rating.
CM
Last edited by cmckenna; Feb 8, 2010 at 12:12 PM. Reason: Poor wording
Thread Starter
|
Registered User
Joined: Jan 2010
Posts: 15
Likes: 0
From: Eugene, Oregon
thank you everyone nor your help it was greatly appreciated. i charged my battery up overnight and put my Alternator and battery back in and fired it up and idled it. it idled fine then after a couple minutes it had a lobe idle at like a big cam type ide and the intake made a sucking sound too then it went away. runs fine now. maybe the computer had to re learn itself. then i did a test. i took the positive cable off the battery while it was running and it stayed running so i put ht back on and tightened it. so my Alternator and electrical is working fine. (an old trick my dad taught me) and my gauges work and read fine. my radio won't work is all so i am going to check the fuse on the radio its self since all other fuses are good. i haven't driven it yet so time will tell.. but seems i got lucky and pcm is fine so far. (knock on wood)
Veteran
Joined: Apr 2009
Posts: 438
Likes: 0
Hall Of Fame
Joined: Jul 2006
Posts: 12,204
Likes: 10
From: Gainesville, Ga.
on newer, computer controlled vehicles, especially dodges, where the voltage regulator is built into the pcm, this is really risky.
its much better to simply test the battery with a voltage meter when engine is off, and see about 12 volts. then test the back of the alternator (or battery) when the engine is running and see about 14+ volts. this tells you the alternator is working. autozone and other places will also test it for free. they can measure voltage output and they can place load on it and measure amperage output. this is a much better option than risking frying your pcm.
glad you got your truck fixed. so what does this mean was wrong? dead battery on your truck?
Last edited by dhvaughan; Feb 9, 2010 at 07:30 AM.
Thread Starter
|
Registered User
Joined: Jan 2010
Posts: 15
Likes: 0
From: Eugene, Oregon
i guess when it jumped wrong it created a voltage spike and killed my battery instantly and there must have not been enough voltage off a jump to have the truck run and act right all together and Alternator never seemed to do a bit of good until the battery got fully charged overnight on a charger is my thought. i am glad i guess i got lucky.