Hey guys,

Just picked up a 1995 Lexus SC400 last night with a bit of an issue starting and I was wondering if anyone has had a similar problem or might know of what the problem could be. As of right now I havent really looked too far into it yet. But I will describe the symptoms.

When you FIRST get into the car after shutting it off or trying to restart it, and you try to turn the car over to get it to start, it will just keep on turning, it wont ever start. So in order to get the car to start I have to pop the hood, take off the lid to the main fuse box on the driver's side and push the "EFI Main" Fuse or Relay *the metallic one*, once you do this you will here a very specific and loud "click" under the engine bay, and inside on the dash the "TRAC" light will come on as well as the check engine light. NOW you can start the car and it will fire up, sometimes the idle will fall below 300 rpm and the car will die and you have to try again, but eventually it will get going and run just fine.

Any ideas?

 

You may have to disconnect the battery for safety; remove the fuse box and inspect for a loose fuse mounting bolt.

Or have a automotive electric shop inspect the fuse box for loose components.

 

When you have an engine problem, please put it in the engine....... forum

 

Thought this was te engine forum for Lexus sc.

 

Sounds like a MAF sensor. The reason it works when you pull the fuse is because its resetting the ECU and its set to run on the base MAF map. Common problems on DSM's, hope my advice helps.

 

theft proof lol

 

Im having a similiar problem right now....I just got it started for the first time in days but removing the MAIN relay then reconnecting it and trying to start it...it idled very low and died out after about 20-25 seconds..

and i can't get it to start again now even though i've done the same thing with the Fuse 3-4 more times now.

So can anyone else think this could be the MAF?

this really sucks, the damn car ran fine just days ago, until i changed the spark plugs/cap/rotor.

 

I just got the new relay in and when I install it the car will not start at all. When I put in the old relay and I finally hear the idle speed sensor "tick" its ready to start again, although if I do not give it throttle it will immediately die and not idle on its own. Once it catches and gets an idea of where to idle its fine.

I also ordered a new idle speed sensor, I am going to change that out with the relay and see if that works. If I have no luck there I am going to the MAF, so I was wondering if anyone has any information on what exactly I am supposed to be getting from the MAF sensor as far as readings if I used a multimeter? Or does anyone know where I could get that diagnostic information?

Thanks,

Brett Thomson

Update: Ran some diagnostics on the car and got back 3 trouble codes, Intake Air Temperature Sensor, Air Fuel Ratio Malfunction *I believe its reading lean,* and finally a volume air flow meter signal. I am 90% sure the Toyota MAF sensors house both the air intake temperature sensor AND the volume air flow meter, so upon repairing this it should solve those and probably my imbalance in air/fuel. Which leads me to my next question.

Anyone have or know where I can get an operational Toyota/Lexus MAF sensor for cheaper then a new *wholesale* one?