[735I4FUN]

Hello all, i am brand new to the board as well as brand new to BMW's. I just bought a 91 735I and i am having some trouble. When i bought it it needed a few little things.
I changed the spark plugs, air filter, and oil.
the car was running great now it has no power and takes 20 minutes to get to 60mph. the only thing i have changed is i put 2 tires on the rear (225-50-15) the fronts are 225-60-15. i was the idiot that went and bought tires and didnt remember the right size. i didnt notice untill i mounted them (in my garage) that they were a different size. the traction control light came on as soon i took it out for a drive and i now have to turn the traction off. But the car is still real slow. i can floor it and it wont get out of its own way.
No lights on the dash are on, no check engine light,no EML, no nothing. its just slow. i am going to put the new tires on the front and i am hoping that with doing that it will take care of the traction control light.
any help would be great. i love this car but i dont think i was ready for the the hassles of owning such a great car.:emo

thank you
Erik

 

[darkhorse737]

ahh..?

transmission problems? bad intenal clutch discs or torque converter bad... or maybe just burnt tranny oil....

try running the car in the lower gears and see if there is a difference.

if u say car "runs great"... i assume engine is in tune.

 

[735I4FUN]

Not sure

the tranny seems to shift fine.
when i shift it manually it will rev all the way up. it just has no power while doing it. its like i am holding 1/4 to 1/2 throttle, even when it is floored. From reading i think this might be limp mode, but i am lost when it comes to fixing it.
when i let it shift its self i get all the way to high gear before i even reach 20mph
any help would be great.

 

[darkhorse737]

will it smoothly rev to at least 3500 in PARK?

For pre 1996 cars, if you believe it is in limp mode, then disconnect battery overnight. That returns your car's computer to ZERO state. reconnect in the morning and re-test.

** make sure u have radio codes in hand ;-)

 

[735I4FUN]

i will check that.

it has an aftermarket radio in it, so i wont have to worry about that.
If it is still doing it in the morning what should i do?????:help
i hate to be a pain, but this BMW is unlike any other car i have ever tried to work on. I am a total DIY mechanic. I will learn in the long run, but it might drive me to drink!!!:rule

 

[Corbinstein]

I'm thinkin limp mode

new here too...
I put mine on jack stands and put her in drive....
wow she really freaked out...
The tire size change may have been the cause...
she may be in limp mode thinking she's skidding cause the rear tires are going faster than the fronts or vice versa...
Hence ASC, and no power...
borrow a tire and put on your spare. Disconnect the battery to reset, etc..
if it works let me know