MIGS

iTrader: (15)

since my old ecu was toast(accordign to a Scan tool), i decided to pick up a used ecu that i pulled from a 93' sc300 (i have a '92). I verified that it was the correct ecu and installed it this afternoon.

after i was done installing it, i took the SC for a drive and immediately felt the lack of power and slow acceleration. the more i pushed the gas, the louder my engine reved, but acceleration was slow as hell until rpms hit 4-5k which then it would accelerate a little better.

did i do something wrong during the simple instal?? i remember that i forgot to disconnect the battery before swapping out both ecu's, would that make any difference? or maybe the used ecu i bought is trash


thanks in advance for your imput/advice

Vincent123

iTrader: (24)

you just made a 2nd identical thread to the one in the performance / maintenance section

soulific

iTrader: (3)

I had this issue after resetting the ecu. Then I resetted it again and it felt stronger. I think you just have to RESET and let the ecu relearn.


My situation, it lacked power again after running strong from the reset. It only reved high as you described with no power.

It turned out to be my clutch going out. Do you have a auto or 5 speed?

My clutch was fine before the reset. I think after resetting the ecu for the first time since getting the car made the car run stronger. Causing the clutch to work harder than usual. Causing my old clutch to go out. Thats just my theory.


You may just have to reset the ecu. Go to the fuse box in the engine bay on the driver side. Pull the EFI fuse. Should be 30 amps I believe. Plug it back after 1-5 mins. And the ecu should reset. After that, drive around hard so the ecu relearns. Driving hard lets the ecu learn to be more responsive I heard. I never tried this learning since my clutch is dead.

You can also reset by unplugging the battery for 10-15 mins I believe.

MIGS

iTrader: (15)

its auto.


i'll definitely unplug the battery, since i didnt bother to do that in the first place. if that dosen't work i guess i'll try that EFI fuse test.

vietunit

iTrader: (5)

I'd try another reset & drive it like you stole it to let it relearn.

Good luck!

czar07

to make the car relearn your old driving habits, disconnect the battery for 10 mins, then take it for a drive. give it some harsh accelerations from stand still, 4-5 times and it should be back to normal.

lexdud

OP, did you replace your old ECu with the EXACT same model # of ECU from the '93? Lexus made many versions (model #s) of ECUs ... even within model years.

MIGS

iTrader: (15)

not sure. I just pulled the "Engine Control" unit out of an 93', and i figered it was a close enough year to my '92, so it would be fine.

there's 4 sets of numbers on the unit, i'm not sure which model #'s have to match. i didnt even think it was that complicated.

DKSc

If you have an auto transmission then the problem seems to be that the new ecu isn't communicating properly with the transmission. The problem you describe seems very similar to a trans slipping, so try reseting the ecu, and make sure all the connectors and pins are tight and not corroded because it may have a problem talking to the trans

Drewbeeee

i replaced mines about 9 months ago with a rebuilt one,had loss power ever since then,i dont know what the problem is..i resetted the ecu today drove around for an hour hauling *** on local roads,still......loss of power anybody got anymore advice,tips,information on what the problem might be,i believe me and net is having the same exact problem...