bubblecoup

Hey, I am having issues with my 1994 LS400. It sat over the winter and now that I have started it back up and tried to drive it the car is running very very poorly. It is rough, it struggles to start and when i drive it, has little to no power when accelerating and wont exceed 50 mph. The check engine light is on but when I plug it in (OBD I) it doesnt display any codes. The car appears to be in limp mode but I cannot say for sure. I checked the air box and filter for any contaminants, everything was fine. I put fresh gas in the tank (it only sat for six months). It ran like a new car before I parked it and recently had a timing belt service last year. There is no obvious signs of internal engine damage. I took it to my mechanic who specializes in Toyota/Lexus thinking it could be misfiring or in need of new spark plugs, both of us noticed rodent foot prints all across the dirt and dust on the engine cover. We have concluded that mice may have chewed wires somewhere and with his estimate for repair in thousands (locating the damage would take several hours) I have decided to try and find the issue myself, before giving up on this beautiful car.
Does anyone have any advice where I should start? I was thinking plug and wires since it seems to be mimicking a misfire, I dont believe there is wiring damage inside the car itself because all traces of animal activity are under the hood (there are nutshells and a nest under the hood, both have been cleaned out) and shows no signs of being in the car. let me know what you think

CELSI0R

Can your mechanic do some basic diagnostics for a minor fee to make sure power and ground to the ECU are in good order? Maybe even just check the communication from the pins to see if signals are okay, if he knows how to do that.

I would say to start checking in the engine bay, since that's where you found the mouse evidence. Before you clean anything, observe where the mouse traveled/lived the most, and where it attempted to make a nest - this can help you target the problem area. Take lots of photos to help you remember what you observed. Also check under the glove box, where the ECU is mounted, to see if the mice chewed through the air box and ate some wires to the ECU.

If the CEL light is on, but there are no codes, I wonder if some ECU wiring was damaged and is causing a short to ground or inhibiting the ECU's ability to communicate properly. Check the related harnesses for that.

A side note - I would definitely change your cabin air filter or at least remove it while behind the glove box. Wear gloves, because it may be contaminated with... mouse stuff... I wouldn't necessarily buy a new filter though unless you can get the car running again.

timmy0tool

iTrader: (7)

sorry to hear your troubles and this one will be hard to pinpoint since you will have to back track as CELSI0R stated and work to find/repair all the wiring that was compromised.

bubblecoup

The mice never made it into the cabin and they did not eat any wiring. We checked the ecu and it had low voltage, my other mechanic believes that there is a short in the throttle positioning sensor and the ecu may need to be replaced.
That begin said, when I was trouble shooting I replaced the fuel pump and the car no longer had a long crank time. So now it starts every time but it still lacks power and takes some time to get up to speed. It is also getting horrendous fuel economy

bubblecoup

Replaced ECU, that was the issue

deanshark

This is why a second opinion is good. Your second mechanic sure saved you alot of time.
Glad to hear ya got it running right again.