Bowtie70SS Posted October 11, 2007 Report Share Posted October 11, 2007 It's been a while since I 've been around here and I gotta post/ask about a really wierd thing that's been happening to the truck. I have had some transmission issues. Number 3 and 4 due to output shaft failure. Now I have a hardened output shaft hopefully that's over. I finally got my truck back together after sitting for a month with the battery unhooked (Red top Optima). The battery was dead as disco, not good. I charged the battery and got it running hooray! I went and hosed off the engine the next day and then the following day REDUCED ENGINE POWER..Sh!t I've been down that road before so I blew out the connectors for the TAC and TB and thought I was good. Nope I was wrong it would go to REP mode randomly or so it seemed. I would restart it several times until finally it would clear. Tonight I had a little 1 hour 3 mile trip and was determined to find out what happened. It got dark outside and I would clear the code and mess with the wiring under the hood at the TB and the TAC module, even swapped out the pedal with another one i had NO GO. I was about to give up when I reached inside the truck to turn it off and accidentally hit the high beams BAM right into REP mode. So I clear out the code and restart it then hit the high beams again...REP mode. So what I am thinking is that my Optima is bad and causing a voltage drop under heavy load that is F-ing up the signal between the TAC and TB. Apparently low voltage there is a problem. Also it seems that when my e-fans would kick on it would go to REP mode. So now I'm thinking that either my battery or my PCM is bad...I'm gonna go warranty out the battery tomorrow. Any other ideas?? Sorry for the long post and I hope not to stay gone for so long this time. Later Dave Quote Link to comment Share on other sites More sharing options...
Bowtie70SS Posted October 11, 2007 Author Report Share Posted October 11, 2007 Forgot to mention that it will go into REP mode with the key on before you even crank it...unless you leave the headights off. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted October 11, 2007 Report Share Posted October 11, 2007 I think you already have it figured it out, sounds like a bad battery. I am surprised your DIC didn't pop up with "Charging System Failure".............then there is also the possiblity that when you hosed the engine compartment down you soaked several electrical connections/sensors that are still wet or are now shorted Quote Link to comment Share on other sites More sharing options...
Bowtie70SS Posted October 11, 2007 Author Report Share Posted October 11, 2007 (edited) Funny thing is that it starts fine. The REP mode has gotten progressively worse (or so it seems). The battery dosen't seem low, but I have been told that it could still be the problem. A buddy of mine runs a repair shop and has encountered similar problems with other late model cars/trucks. A bad cell/shorted battery can do wierd things. BTW I have a 140amp alternator from a H2 that I installed with the e-fans and the volt gauge on the dash does not drop below 12. I guess I need to check my negative cable also from where I had it unhooked. Edited October 11, 2007 by Bowtie70SS (see edit history) Quote Link to comment Share on other sites More sharing options...
hot rod truck Posted October 11, 2007 Report Share Posted October 11, 2007 Dave, Get the alternator checked. Make sure that it's putting out the correct amperage/voltage. I have seen many times where a bad battery will overwork the alternator causing it to overheat and fail. Since REP occurs when the e-fans or hi-beams are turned on, it sounds like the alternator is not meeting the amperage demand needed to run the truck. Good luck. Brian Quote Link to comment Share on other sites More sharing options...
Bowtie70SS Posted October 11, 2007 Author Report Share Posted October 11, 2007 I guess it's possible the alternator is bad, but the battery went dead with nothing hooked up to it. Also I was reading up on P1518 and one of the TSB's says "Inspect S102 if there is a P1518 stored. S102 is in the engine harness and is 5.5 inches from the MAP sensor." Ok what the hell is S102? Is it a fuse link or some kind of connector? Dave Quote Link to comment Share on other sites More sharing options...
SSThunder Posted October 11, 2007 Report Share Posted October 11, 2007 a bad battery will cause the alt to go. Hope it's just the battery and not the alt. Quote Link to comment Share on other sites More sharing options...
SS_bnoon_SS Posted October 11, 2007 Report Share Posted October 11, 2007 I actually went through something similar last night at the car wash... When they brought it out the other side, they shut it off to do the final detailing and it wouldn't restart. I went through the trouble of swapping a few parts out that I happened to have on hand "just in case", but the truck still wouldn't run. It just flashed the check engine light and came up with "reduced power" in the DIC display. Finally the battery was starting to die from cranking and not starting, so I had my wife swing by and we jumped it and it fired right up... this morning it worked OK, but it did crank kinda hard compared to what it used to. Probably time to install a new battery. I hate it when maintenance items dip into the mod money account. Quote Link to comment Share on other sites More sharing options...
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