help!!!!!!!!!!!!!!!

[ls1ta1999]

Think my pcm took a dump
Hey guys i have slight problem my car 99 trans am m6 was running fine yesterday then i parked it in the garage and left it there untill i got home from work today. i started it up ran fine then when i got back into the car i noticed that the tach,water temp, and fuel gauge dropped out and the car kind of got a lil miss to it . i could not not connect my computer to it. so i then checked all the fuses, i checked for power and ground to the dlc connector. then i checked continuity from the data wire to the pcm and the wire was ok so im thiniking the pcm? it just happened all of a sudden car ran fine the night before or am i missing something? before i order a new pcm?


thanks,
Scott

[ls1ta1999]

hey thanks , i checked the connectors and the pins all seems ok batt volts are good 12.7 i was wondering if possibly when my altenator started acting up dropping to 7 violts then back up to 14.8 if that may have spiked it . i have a new alt im putting in and ive checked all my grounds and checked for breaks in the data wire . car starts up great then breaks up if u rev it up to 2500 rpm and sounds teribble im going to order new comp im just trying to rule out what caused it so as i dont stick the new one in and have the same problem i honestly think its the altenator it did this after that started acting up . thanks for responding i appreciate it !

[ls1ta1999]

hey i installed a new altenator and just rechecked everything for a second everything worked then dropped back out i still cannot connect the laptop to the dlc there is no signal comming from the pcm and just to be safe rechecked all grounds also i let the car run and still no luck i rechecked all the pins even took it out to see how it felt on the pin from the pcm nice tight fit. im fairly confident the pcm got fried i cannot get a signal out of it throught that data wire pin 58 dark green thanks again

[ls1ta1999]

no i didnt luckily . im assuming it was a spik the alt was messing up while i was driving it would drop to 7 then back up to 14 only thing i can think of i had parked it for the night hopped in after work and thats when i noticed it acting up

[ls1ta1999]

hey i had a guy at work today look at it hes very very good at all that electronic stuff i was telling him what happened and he checked out the pcm and said it seems to be a logic failure i had crashed the car earlier in the year (last jan) it had gotten up to the middle of the winshield in water. i cleaned and replaced alot and also checked to see if water had gotten into the pcm and it was dry when i took it apart the other da there was some condensation on the power transistors on the sides nothing seemed to smell burnt or looked fried so i think maybe since it had been through hell it finally gave up the other day lol im going to order new pcm this week and slap her in there . but thanks alot for responding and helping out i greatly appreciate it !

scott

[ls1ta1999]

sooo i found out what the problem was after going nuts for almost 2 weeks the gauge cluster i had bought was bad i found a resistor in the data wire on the cluster side burnt out well burnt out finally but owuld get hot and open causing the data being sent from the computer to get all jumbled and when that resistor would heat up it would spike the computer . i unplugged the cluster and hooked right up . its always something stupid lol