01LS430

Need some help everyone. I have a 2001 LS430, 152k miles. At full throttle, the car just does not move. The rpms reach about 4k and kinda just sits there. The plugs were replaced at 110K, regular Mobil 1 oil changes every 5K miles, new air filter, new knock sensors, new MAF sensor, new TPS. Radiator was replaced at 100k for a leak and coolant was flushed 2k miles ago. The car isn't throwing any codes. If I drive at ~50% throttle or less, it seems ok with a little hesitation between 2nd and 3rd gear.

I just took the car out for a drive, hit full throttle a few times, and when I got back to my driveway, I looked under my car and there was white smoke coming from what appears to be an exhaust leak behind my driver's side catalytic converter. I've always known white smoke to be coolant, but my coolant is still full. Can anyone shed some light on the situation?

KING

iTrader: (1)

Sea foam cleaner, give it a try. It should give your engine a good cleaning.

semar

headgasket?

01LS430

I ran seafoam through it at 150K miles. The plugs were also replaced with iridium plugs at 110K.

Is there an easy way to diagnose a bad head gasket? I don't see anything out of the norm between the heads and the block.

Lavrishevo

iTrader: (1)

If you have an exhaust leak you should have that fixed right away. This can affect back pressure as well as fuel to air ratio because of misreadings at the O2 sensors. Forget seafoam or anything else like that. First start off with fixing the exhaust leak and make sure yours cats are not blocked or clogged.

KING

iTrader: (1)

Exhaust leak is not going to have such a huge effect. I have cutout that's open all the times, and my car runs strong. Back pressure is important, but a leak isn't going to cause the problem described.

And I think if any cats are clogged you'll get a code right away, because the air mixture won't be right and the O2 sensors will go crazy.


Did you check the fuel chamber? Now that might be clogged.

rkw77080

I would start troubleshooting with the basics...

The LS430 has a drive-by-wire design, that means the accelerator pedal does not actually have a physical cable connected to the throttle valve of the engine - instead, the throttle valve is operated with a motor which is controlled remotely and electrically by the accelerator pedal.

In our case, I suspect the throttle motor or sensor may be failing. I would start by checking if the throttle valve opens the full range in respond to the accelerator pedal.

Owczar

On wide open throttle ECU goes to open loop without readings o2 sensors.

rkw77080 is right. You should check this way.

You can use obdII reader and record sensors reads during drive.

Example RPM, TPS, acceleration position sensor, MAF, and o2 sensors 1B1 and 1B2.

On WOT TPS should be around 80% at LS430.
Here you have example data. At 1:29 there was WOT.


You can check AFR also with wide band o2 sensor. It should be around 11.8-12 on WOT.

yuri.ber

iTrader: (7)

Change both fuel filters and see what is going to happen. I assume car drives normal if you push the accelerator smoothly.

01LS430

Thanks for the help everyone. Ended up being a bad coil and faulty tps.

jimbosr1

glad your 430's back to normal

semar

what is tps?

02Legend

iTrader: (3)

Throttle position sensor

rkw77080

For troubleshooting procedure, take a look at Step 4 on Post #7...

DrewLS430

Wow glad I found this. Having same issue with my 02 430. Gonna swap out all my coil packs, plugs and my TPS and hope this fixes my issue or gonna have to bump this up!