whiteshark

First timer here.
First thanks to this community for getting me this far. I learned alot just reading more posts than i can remember.

I have a 94 ls400. Bought it 3 years ago with no issues. about 2 years ago the dash lights would flash on and off in the winter until the car got warm but i lived with it.

8 months ago power steering fluid started leaking. I was sure it was not leaking on the alternator but could not find the leak and could not afford to fix it. so i ran it with no fluid in the system for 6 months an developed popeye forearms.

3 weeks ago I find the leak in a hose running in front of the radiator and took it off and replaced the hose.
Filled system, worked out the air and no leaks. Then started to notice the infamous smoke out the tail pipe and assumed just a coincidence that it started burning oil at the same time the PS was finely fixed.

then started having to add ps fluid again but no leaks anywhere.

I probably put in 5 quarts of dex/merc ATF in the system between replacing the hose to seal up the PS system and when I learned of the issue with a bad air control valve. This faulty was sending ATF back into the engine. So I stopped filling it.

I ran the car 3 days a total of 45 miles without adding any fluid. Aside from working on my popeye forearms again to turn the steering wheel, all was well.

By well i mean car was running smooth as silk just tuff to turn the wheel.

This morning i started it up and it was rough feeling and sounding engine and exhaust especially from under the mid section of the car. very little power. hard to get it to go 45-50 mile an hour.

Could all that ATF going into the engine be sitting in the catalytic converters and causing some exhaust flow or compression issues? Any ideas before I put the the new air control valve on?

PureDrifter

iTrader: (10)

i suggest you read the stickies so you can easily find the bible...
http://www.clublexus.com/forums/ls40...ing-bible.html

whiteshark

Thanks PureDrifter,
This Bible thread is great and was the ahha moment in my research that helped me nail down the air control valve issue.
Now wondering if all of that ATF that found its way into the engine and exhaust system is why i have the power loss issue??

tried to outline step by step what i have experenced and done in the original post, but sure could have done a better job.

So new to this forum method of communication i am not sure what you mean by stickie.
Show ing how nu i am to this.
Best and thanks for the interest in helping me.

deanshark

The "stickies" are just the first few threads that will always be at the top of the page b/c they have the most common questions and answers to most problems. Being new to the forum you will probably want to check out this site; http://www.lexls.com That will also help ya out alot more. (common fixes)
Welcome to CL and remember to use the search feature as much as you can, you'll find alot of helpful info that way.

whiteshark

I think I am on top of the air control valve. As mentioned at the end of my post, I now have a new issue and am trying to figure out why i suddenly have this big loss of power.

I am guessing at why near the end of my post but looking to see if anyone has any experience with this. Thanks for your response.

Perhaps i should find a way to be more clear about the fact that the ATF loss issue is resolved but now have a power loss issue.
Again thanks.

whiteshark

After alot of searching I am still guessing. Does anyone think the power loss and rough/loud exhaust is due to large amounts of ATF building up in the CAT's?
Best

PureDrifter

iTrader: (10)

doubtful. if the cats were bad they would be clogged, and turn RED HOT from the backpressure they'd introduce into the system. the majority (if not all) the ATF being introduced into the intake was burned off.

it's something else, you need to check for fuel and spark all around.

whiteshark

Checked codes and here is the status.

25 - Air/Fuel ratio lean malfunction
28 - Main oxygen sensor signal (on right bank)

so those are my codes and the car is loud rough and has 30% of its normal power.

Again, I know i dumped a lot of ATF into the engine as a result of the failed air control valve but there is no ATF in the P/S system now after i realized that the ATF was going into the engine.

I know i need to replace the air control valve on the P/S pump.

If I replace the main oxygen sensor on the right bank I am assuming it makes sense to also do the left bank?

I am also wondering if this will correct the lean air-fuel issue?

I appreciate any input.

whiteshark

Thanks for all the input.
Finally back in town and checked the cats.
After a 15 minute drive with max speed of 40 mph while dark outside, I looked under at the cats and both red hot.

Given the timing of all this i do think it was all of the ATF backing into the engine due to failed air control valve.

Now need to order 2 new cats, jack it up and replace them. Not sure if i am going to plug the air control valve on the PS pump or replace it at this point. I am thinking of trying to remove the O2 sensor per code 28 and cleaning it before replacing it with a new one.

Any thoughts on trying to clean the O2 sensor instead of replacing it?

Ill post what i do and the results after the new cats are on.

thanks to all of u for weighing in on this. Cant wait to get the new cats cause I miss my ls400.

trukn1

Replacing the O2 sensor should alleviate the running rough problem as well as improve your fuel mileage (which I am assuming is pretty much in the toilet now as well) It IS such a hasssle to replace them but since you are down there ANYWAY, and are already in the area, you might as well replace both of them and just get it over with. This SHOULD corrcect the lean problem you have ( I have to do the same to my 92, so I know your dilema). Also, if you do a search, in these forums, under the keyword "Coolant temp Sensor", that coupled with the O2 sensors will get rid of the problem. Coolant temp sensor is a "while you are at it item", since you already pulled the O2 code and identified the problem you have. O2 sensors, and I wouldn't skimp here, can be a little costly to replace but they are vital. You can find cheaper one's, that you would have to wire up to fit the terminal fittings, but you run the risk of having them not be in ohm spec for the 400; remember while all products, that fit, may be applicable to your car, not all are created/operate equally.

Plugging the PS Pump is a cheap fix and will yield satisfactory results,,that way the Popeye arms can swell down.

Start there with the O2 sensors before dumping money into the cats, essentially b/c cats aren't cheap. Am also assuming that you need the O2 sensors for the upper bank (LS has 4 O2sensors 2 uppers and 2 lowers). With the Air/fuel mix beiing off, the cats are bound to run a little hotter than normal. Rule of thumb,,,start with the cheapest and most easily accessible fix first, before moving on to something more complex. Never a good thing to just throw parts at the car b/c while every little thing you throw at it WILL help an aging car,, you WILL notice the noticable drain on your wallet.
**Food for thought***

whiteshark

Ok. I ll order the O2 sensors and install them first.
I was understanding that if the cats were red hot like that they were shot and needed replaced cause the metal was melting.

Your logic is solid though so Ill start with the both O2 sensors and the coolant temp sensor as suggested.
Thanks trukn1.

PureDrifter

iTrader: (10)

you will end up replacing the cats anyways.

once they get that hot the catalytic material will basically melt and eventually force itself out the *** end of the car if you keep trying to drive it.

whiteshark

It has been a while but wanted to provide an update.

So here is what happened: The air control valve failed and the PS fluid (dex/merc) was sucked in to the engine. The PS fluid does not atomize(burn) well and consequently filled up the cats. the clogged cats restricted exhaust flow and overheated. The Ceramic honeycomb material was destroyed and some of it has likely found its way into the resonator.

I have replaced the engine coolant temp sensor, both upstream O2 sensors, and both cats.

Still ran rough and low power. Can drive it for more than a 10 minutes or cats start to heat up again. Mostly at the backside flange. I have driven it 7 miles since new cats and O2 sensors have been put on.

Next I need to replace the resonator. I have 2 options. 1.) cut the resonator off and replace it with a straight pipe (about $80-100 parts and labor) or 2.) remove the entire center pipe section, Part # 17410-50021
http://www.lexuspartsnow.com/parts/l...410-50021.html

(this is about $550 part and an hour of labor).

The bottom line is that the 5 quarts of PS fluid caused a world of damage to the exhaust system.
once I replace the resonator ill provide what i hope will be a final update for the group.

PureDrifter

iTrader: (10)

you replaced the cats and it still isnt running right

it's ot the ATF, you need to figure out why your car isnt running on all 8 cylinders and/or running pig rich.

the LS doesnt use ceramic honeycomb, it uses metal substrate cats, which are far better flowing and consequently more expensive.

mikes7ke

iTrader: (1)

Did you check for codes after replacing the o2 sensors?