ozbear

Hope this works am looking for advice/help with a strange situation. Here goes..........

My CEL and trac off lights come on whenever I drive UNLESS I slip it into gear quickly and set off on the road. They will then only come on when I slow almost to a stop. Then they will stay on until I repeat the into gear quickly trick. When they are on I get poorer milage but not real bad. I used the paper clip trick to check the codes and got 13 and 28 which I believe mean "RPM Signal" and "Main O2S" according to troublecodes.net. After looking through the forums I found nothing that seems to relate to this situation except that if it is an O2 sensor problem I need to sort it out quick or risk ruining my cats. Car is a 90 LS400 with 120000km ( 75000mi ) on the clock. All I need to know is what to look at next or how to fix. Many thanks.

nthach

code 13 is a Ne signal problem coming from the cam sensors in the distributors.

GliTCH

assuming the sensor is working properly could that indicate a misaligned timing belt? i just got my belt changed and now my CEL is on with code 13

ozbear

Good point - I had my timing belt done very recently too. Would think though that a wrongly aligned belt will cause the engine to run like a total pig. Mine's still smooth and quiet. Have you had it checked at all?

GliTCH

my engine runs smooth if i accelerate gently.. under half throttle to WOT it starts cutting on and off. i got it checked out by the guy that did my belt and he was trying to say it was my torque converter at first.. he tried to prove it with a diagnostic computer displaying the knock sensor.. i think hes full of it. he sensed that too and told me it could be the plugs i changed right before i had him do the belt, i had the bosch +4 platinums and so i got the NGK laser platinums instead and installed those.. it's either just the same or a little better but still.

im taking it to lexus tomorrow

nthach

if the knock sensors went off, you would feel the ECU pull back timing. Take to the dealer and have them check out the work, there is little margin of error in the 1UZ engine.

ozbear

If the knock sensor detected anything wouldn't it throw it's own code? I'm working under the assumption that the "RPM Signal" ( engine is revving a little high before settling to idle even when warm) has been caused by extra fuel being forced into the engine as a result of a faulty O2 sensor. Probably the sensor(s) need to be replaced anyway due to milage and doing this should clear both problems. Just want to be sure that they ( may as well do both ) are faulty or if anything else could cause a code 28. Will find out tomorrow how much the sensors are going to cost in Australia.

GliTCH

took it to lexus, it was a misaligned belt (had no idea a car could run so good with a bad timing belt install). they made it right and charged me way less than they quoted me, even loaned me an ES330. got the car back, no more CEL or hesitation, runs great except the vibration. lexus recommends replacing engine and tranny mounts

ozbear

Checking with local dealer to see whether timing belt misalignment can throw that code in a 400. Will be a right PITA if it is the case but I guess we'll see. Thanks for the info