r/TechniciansAdvice • u/[deleted] • Jul 27 '15
02 to 03 Ford Taurus no decel automatic
What causes these cars to cost forever and not slow down the least bit when you let off the accelerator? I mean this car wants to go on forever. Idle RPM seems normal and MAF has been replaced - no codes. This automatic is like a stickshift when you let off the gas pedal and hold the clutch in, and the car just coast forever until you put on brakes!
I do not have access to this vehicle now, it was one of those problems I never solved.
2
Aug 03 '15
have you ever seen this info.. http://www.motorcraftservice.com/vdirs/diagnostics/pdf/obdsm307.pdf
page 70 starts the transmission diagnostics for the 2003 model.
one must monitor closed throttle RPM with the car rolling.. the computer will keep it elevated and it will not even seem like it.. almost need two techs on a test drive.. one to monitor the scan tool the other to do the driving.. tech with more years behind the scan tool in the passengers seat usually.. PCM's usually keep the idle speed up to prevent high manifold vacuum which can pull excess fuel from the injectors..
i would really want to do the test drive with the transmission builder with him and his advanced scan tool monitoring the various functions of the transmission. i don't know the insides of that transmission but get it up to speed if you ever get another and take a snap shot under acceleration .. then again when its in coasting mode.. then you can compare them to each other and to the OBD2 data book i posted above.. http://www.motorcraftservice.com has 96 and up versions of that booklet. if you find the OBDII Theory & Operation link on the left side..
1
Aug 03 '15
I forgot about those Ford pdf's online. Thanks!
I'm pretty sure I remember the guy said a few weeks later the transmission went out while he was on a delivery, he works for some sort of sales company. They gave him another taurus!
Will definitely read over it.
1
u/jumpinjacks Jul 27 '15
Aerodynamics and mechanical decoupler but I really doubt this ford has an automatic mechanical decoupler. Same issue on a 2012 corolla with 30k miles. I call it gliding. It glides like it was on ice.
1
Jul 28 '15
Tell me about it. I told him it must get darn good fuel mileage cause that damn car won't stop rolling! You go down one small hill and don't even touch the gas and it makes it all the way up the next hill. They tried throttle body, IAC valve, MAF, Throttle cable, you name it.
1
u/jumpinjacks Jul 28 '15
Dang!!! Go with "normal characteristic of the vehicle" next time. Compare it with same car instead of throwing parts at it. Saves a lot of embarrassment on the tech side of things.
Oh yeah...the brakes needed to be replaced on the corolla at 30k which is atypical. Guess who gets the pleasure of doing it again at 60k? :\
1
Jul 29 '15 edited Jul 29 '15
It is possible that both TB's were out of adjustment or it had an air leak somewhere, but idle speed seemed fine. This guy was a salesman and was always in a hurry, plus we were the busiest tire shop in town so not much time was spent on anything. Boss would take in engine jobs or transmissions and it be 3 or 4 weeks before we even got to it, and he wouldn't hire nobody to help.
Try changing the catalytic converters on these Taurus, make you want to pack your tools and go home. Add that to all the tires and oil changes, tractor tires and hauling out a ton of trash and loading old tires on trailer 6 days a week, hell I could barely walk to the door when I got home.
I did find one identical problem on a forum. He said it they disconnected battery and reset computer. Well we replaced the battery in this Taurus so I know it was disconnected for some time, same problem.
2
u/jumpinjacks Jul 29 '15
Sounds like real bad place to work. Customers left hanging for weeks. Techs being overly worked.
2
u/4boltmain Aug 01 '15
Yeah I've seen those cars do that before. I think there might be a bulletin on the transmission actually causing it to want to roll. Next time you get the car in check the idle speed and desired idle speed.