MartinL

I just got this car last week. Everything went fine. It has had the ECU replaced. The muffler has also been dropped and remounted causing a small exhaust leak at the donut gasket. Everything has been running fine. It has started shutting off when you accelerate over about 1,500 rpm. However, it will crank right back up. Finally today it will not crank back up. Before dying the last time the speedometer stopped working beforehand along with the rpm gauge (speed sensor?) Before when it would crank back up it would show the battery light. I just bought a new battery, however the terminal is disfigured and needs to be replaced, but hasn't caused a problem. When you try to crank it back up you can tell it wants to start but something is telling it to shutoff before it can fully start and idle. I am going to try reseting the battery in a bit and see what happens. I'm hoping that maybe I need to replace a capacitor or something minor. Ughhh. I just got this car.

MartinL

I just got this car last week. Everything went fine. It has had the ECU replaced. The muffler has also been dropped and remounted causing a small exhaust leak at the donut gasket. Everything has been running fine. It has started shutting off when you accelerate over about 1,500 rpm. However, it will crank right back up. Finally today it will not crank back up. Before dying the last time the speedometer stopped working beforehand along with the rpm gauge (speed sensor?) Before when it would crank back up it would show the battery light. I just bought a new battery, however the terminal is disfigured and needs to be replaced, but hasn't caused a problem. When you try to crank it back up you can tell it wants to start but something is telling it to shutoff before it can fully start and idle. I am going to try reseting the battery in a bit and see what happens. I'm hoping that maybe I need to replace a capacitor or something minor. Ughhh. I just got this car.

Legender

These cars are very power sensitive... needs to be clean and strong... I would definitely not mess with anything until you get the terminal changed out. You've got some other issues it seems...but get the right power to the right places and then start your trouble shooting....

LScowboyLS

generally when the speedo and tach are messing up intermittently, as well as the kind of running/starting problems you have, the problem is in a quite short list, as shown below:

● bad battery
● bad battery connections
● bad alternator (almost always due to power steering fluid leaking on to it from your power steering leaks)
● ECU capacitors
● bad ground (check both ends of the each ground strap including the one at A/C compressor and the two at rear of engine)


please do the following steps to get us started on solving it for you:

● tell us the year of your LS400
● replace the + battery terminal with the part from the dealership (about $15-$18 - also stocked and probably slightly cheaper at any Toyota dealership)
● take a voltage reading across battery with vehicle off
● take a voltage reading across battery with vehicle on at idle with headlights on
● take a voltage reading across battery with vehicle on at 2000 rpm with headlights on (have partner hold rpm at 2000)


one of the most likely suspects, ECU capacitors, isn't solved via a replacement ECU, because the different ECU has the same old and/or defective capacitors as the first ECU had, if I am making sense

funtimez

I had a similar situation with my old altima not sure if it will help you. It would shut off and start back up by itself while still driving. Maybe your problem could be your camshaft position sensor or crankshaft position sensor. Not sure though cuz im new to lexus and im just figuring things as they come and go but that might be a good place to start.

RA40

iTrader: (6)

What year? When was the ECU replaced?
Have you tried reading the codes?

shanjam

do the battery terminal, check charge rate ,if altenater coverd with power steering fluid steam clean altanator

johnnyg66

Just my 2 cents. Today i changed my positive battery terminal. Bought it from Sewell along with other misc items. Took all but 5 mins to complete. Just a few pics of new/old.