Holty Posted September 5, 2006 Report Share Posted September 5, 2006 ok, first, sorry if this is in the wrong forum, i didn't know where else to put it. ok, so i'm driving to work today, about 3/4 of the way there of a 29 mile trip to work. i'm coasting down a hill on the interstate, somwhere between 55-65mph, can't remember exactly, all of a sudden, the truck has a slight backfire (not real loud), CEL flashes once, and the doors unlock/lock all within a split second?! now this isn't the first time this has happened, but it seems so random, i can't see any cause for it. can somebody please tell me wtf is going on here? oh, btw, i did happening to be logging at the time, but looking at my scan, i cannot see anything out of the ordinary of why this happened or what caused it. Quote Link to comment Share on other sites More sharing options...
Krambo Posted September 5, 2006 Report Share Posted September 5, 2006 Could be way off base here but is your battery cables on tight? Did you have a momentary power blackout on your log? My truck does weird things as well. I get a security "lock" light once in a great while which goes out in about 3 seconds. Quote Link to comment Share on other sites More sharing options...
Holty Posted September 5, 2006 Author Report Share Posted September 5, 2006 Could be way off base here but is your battery cables on tight? Did you have a momentary power blackout on your log? My truck does weird things as well. I get a security "lock" light once in a great while which goes out in about 3 seconds. hey man, thanks for the reply. nope battery cables are TIGHT, checked them already. don't see any blackout in the log, but who knows? i sent it to zippy to see if he can find anything.....weird, just weird. Quote Link to comment Share on other sites More sharing options...
Krambo Posted September 5, 2006 Report Share Posted September 5, 2006 Remote start? Quote Link to comment Share on other sites More sharing options...
Holty Posted September 5, 2006 Author Report Share Posted September 5, 2006 Remote start? i guess anything is possible, but its been installed since i got the truck, so about 9months and no issues until recently. i would say within the last month or so. Quote Link to comment Share on other sites More sharing options...
Holty Posted September 5, 2006 Author Report Share Posted September 5, 2006 also, if it was the remote start killing the engine, why would it unlock/lock the doors? that only happens when i put the truck in Park. just thinking out loud here. Quote Link to comment Share on other sites More sharing options...
zippy Posted September 5, 2006 Report Share Posted September 5, 2006 That is rather strange. It certainly sounds like an electrical failure of some type. Possibly a loose piece in the circuit board from what it sounds like. Quote Link to comment Share on other sites More sharing options...
Simon Posted September 6, 2006 Report Share Posted September 6, 2006 Last winter I had strange codes and weird shifting coming out of my ford work truck. It was fixed buy unplugging the 78 pin connector and cleaning it. Maybe you just have some dirt/oxyde somewhere on a connector. Quote Link to comment Share on other sites More sharing options...
Justin Lamanna Posted September 6, 2006 Report Share Posted September 6, 2006 Last winter I had strange codes and weird shifting coming out of my ford work truck. It was fixed buy unplugging the 78 pin connector and cleaning it. Maybe you just have some dirt/oxyde somewhere on a connector. <{POST_SNAPBACK}> Ford, enough said. Quote Link to comment Share on other sites More sharing options...
Simon Posted September 6, 2006 Report Share Posted September 6, 2006 electronic is electronic I have a degree in electronics. No matter what fagin' brand it is when you have a dirty connection it won't be a good signal. Quote Link to comment Share on other sites More sharing options...
SSThunder Posted September 6, 2006 Report Share Posted September 6, 2006 my ss has backfired once and that was from bad gas. The electrical stuff is weird. Hope you PCM isn't getting ready to take a dump. Quote Link to comment Share on other sites More sharing options...
Quik Posted September 6, 2006 Report Share Posted September 6, 2006 on the firewall there are those studs that grounds are connected to. if the stud is loose and they do come off sometimes. mine did your truck will act goofy. these are teh ECU ground and ones another one. they both need to be attached and i think there is another one next to it. as for back fire tht would be the spark being cut and then relit. doors locking and unlocking that would also befrom cut in power check for all the grounds on the motor to see if any came loose or see if any are fired from to much amp draw thru them or another possiblity. your MVPI pro grounds itself thru the OBDII port, which also grounds itself. so if your laptop is backfeeding or your Pro is going bad it could be giving issues to the ECU Quote Link to comment Share on other sites More sharing options...
SS_bnoon_SS Posted September 6, 2006 Report Share Posted September 6, 2006 also, if it was the remote start killing the engine, why would it unlock/lock the doors? that only happens when i put the truck in Park. just thinking out loud here. <{POST_SNAPBACK}> I'm vote #2 for remote start. There should be a main power supply circuit to the remote start unit, which breaks the switched power main source to run the truck. You can test this by driving down the road, turn the key off, then back on. You may or may not actually get the backfire, but the door locks will lock/unlock/etc. and I'll bet my supper that it's what it is. The burst of fuel not getting ignited as the key turns off, then exploding when the power comes back on is why you get a backfire. I used to install these things and I've diagnosed this problem several times and it's exactly what you're talking about. One tip, if they used the crimp on solderless connectors, remove them from the main power circuit connections and solder/heat shrink them. The high current kills the connections pretty quickly. Quote Link to comment Share on other sites More sharing options...
ccgoodwrench Posted September 10, 2006 Report Share Posted September 10, 2006 Check your PCM wiring harness bolts. Theirs two of them make, sure they are tourque. My were lose and cause a prolbem like that. Quote Link to comment Share on other sites More sharing options...
Holty Posted September 11, 2006 Author Report Share Posted September 11, 2006 thanks man, i'll check that out. Quote Link to comment Share on other sites More sharing options...
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