aj350925

Last week I changed the starter in my LS400. It took 5+ hours. The starter was defective......So I changed it again. When I went to start the car it initially chugged a few times and died. I was not worried bc I thought it was air in the fuel system and in a few starting attempts it would be fine. I was very wrong. the car starts (barely) and begins to idle at ~400 rpm. The idle is rough and not as smooth as it would normally be. If I give the car throttle it revs to ~~800 RPM and then dies. I put a scanner on the car and it gave me a code saying accelerator pedal position sensor malfunction. I changed the APPS out and it did not help. I pulled the plugs and the plus on the passenger side bank look good and on the drivers side looked almost wet and fouled. I changed the plugs.

What could be wrong, what should I try next. I tried to change the starter and now I have put 500+ dollars and 50+ hours into my car and I cannot even keep it running.

Help me, clublexus posters; you're my only hope.

LiCelsior

iTrader: (32)

did u plug back in everything? ign coil and did u mess with the tps sensor?

aj350925

Last night I took everything back down to the intake manifold gaskets and put it all back together slowly with 2 other people to make sure I didn't miss anything.

I have not done anything with the TPS, the TPS was next on my list of things to check.

Please help me form a list of things that could be wrong. Whatever broke had to of broke from being move/pulled/bumped.

I unplugged all the coil over plugs and all the injectors(to take the intake manifold off), but I don't think I have an injector or spark problem. My guess is something on the throttle body.

mclarenf1k

iTrader: (1)

LOL Just had the same thing happen to me. Eager to hear a response.

aj350925

If this just happened to you why are you laughing??!! I think I am going to keep my trend of throwing expensive parts at it, and change the tps tonight.

If you figure out your problem, please post what happened. I will post what happens with the TPS.

mclarenf1k

iTrader: (1)

Can't help but laugh. What's the chances that someone else runs into the same thing around the same time!

On my lunch break, I discovered a small fuel leak from a line on the driver side somewhere. Gonna pinpoint it tonight. My car has the same symptoms; idle at 400 and dies off. I'm also getting white smoke during idle.

So in my case, I'm banking on a possible fuel pressure issue. But all it takes is air/fuel/and spark. Process of elimination.

Have you checked your MAF?

aj350925

I have not checked the MAF. I don't have any fuel leaks or smoke either.

mclarenf1k

iTrader: (1)

Fixed my fuel leak, and the car still doesn't start.

On the hunt for the cure once I get off work. I know its got to be something stupid.

mclarenf1k

iTrader: (1)

SHE'S ALIVE!

After double checking my work; fuel system, connectors, vacuum lines, EGR system, air intake, throttle body, I was coming to a mind blank.

A quick Google search for code 15 on an LS400 pulled up a guy on the UK boards that had the same issue. He mentioned checking his IGNITER. Makes sense! Car fires up, but dies right away....obviously an ignition issue, especially with relays and fuses ruled out.

Pulled my igniter off, and behold, the lower connector, which isn't visible unless you remove the igniter, completely unhooked. When I was removing the lower plenum, the corner must have caught the harness and pulled the plug out.

Plugged it in and fixed my issues.

She's running like a champ!

aj350925, not sure if any of this helps, but looking at your symptoms, you may be in the same boat as me as far as it being an ignition issue. I got lucky with a simple fix...hopefully turns out the same for you.