karthick

My car (1993 LS400 120k miles) which ran ok otherwise was stalling when I shifted to Neutral so I got the problem diagnosed at a toyota dealership.
It turns out that the Intake Rubber Air Hose ("The dealers description" ) has a leak.
He wants $300 ($45 labor, $255 parts) to replace the rubber air hose !!. Now, I dont know any rubber hose that costs $255 .. I called up Carson Lexus and I was told that the intake system has two parts

Part 1: Small Rubber hose $55 (Runs from airbox to Mass airflow sensor)
Part 2: Metal part (Runs from MAF to engine).

I wish I had the car with me so I could take pictures...

I dont think the metal part sprung a leak (unless at a clamp), which leaves the rubber part .. but $250 !! for a rubber hose.. Seems weird.

Anyone have an idea what the dealer is talking about? Which parts is he talking about..

I know those things are sturdy.. but even then...for $250.. I think I am going to find some heat resistant tape and see if I can fix the problem temporarily...

Och

iTrader: (3)

He's lying. Read my post https://www.clublexus.com/forums/sho....php?t=228418&

karthick

Wow.. Superb write up on cleaning the throttle body..I did a search before posting and there were suggestions that a leak in the air intake system might cause the stalling too.. Hmm... anyway, I will tell him not to fix it for now... and lets see how it goes..
First project = Find a good independent mechanic in Denver !!

Och

iTrader: (3)

Well first of all its very unlikely for the intake system to develop a major leak - there are no moving parts. There are actually two rubber hoses, one from the intake to the maf, and another one from the maf to housing that connects to the throttle body. All of these are very sturdy, and wouldn't develop a leak for no reason. If they are, just find it and caulk it or tape it. Check if all the clams are tight.

If anything, it couldnt a leak of one of the vacuum hoses that are connected to the intake hoses, which is also an easy fix, these are standard hoses you can buy in Autozone, etc.

Furthermore, there's no reason for the car to stall because of an air leak. Air leak just means your car is sucking in unmeasured and unfiltered air, so you are potentially sucking in dirt into the engine, and fuel/air mixture isnt right, so your car may run too rich or too lean - most likely lean, too much air, not enough fuel. You would actually feel that when revving the engine hard, but not stalling when shifting to idle. I ran mine with the whole intake fully disassembled and maf disconnected, the air was sucked straight into the throttle body, and there were no stalling problems.

Just get your throttle body cleaned out. This is an extremely common issue on our cars, and cleaning throttle body solves it most of the time. Check out lexls.com for DIY instructions.

Loiosh

Awesome thread, Och. ++

karthick

This kinda changes the topic of the thread but it is a folllow up to the original posting. So I told the dealer I am not fixing the intake hose. But I did get a bunch of other stuff done to my car..
I got the car back from the Toyota Dealership. I got the following work done.
1. Install a new air strut
2. Install a new coolant tank/cap/coolant level sensor
3. Install new rotors/caps/wires/plugs
4. Fix all the power windows .They redid a bunch of wiring work...

Now even after replacing all the rotors/caps/wires/plugs, the engine is throwing a check-engine-light but not throwing a code.

The engine seems to be misfiring even now and there is absolutely NO power.. The idle of the car is fine but when I have the car in Drive and I am at the stoplight, the whole car shakes, not sure if that is a related problem.
When I mean no power, I mean NOOO power.. I have to floor the Gas pedal to be able to make it up a gentle hill. The engine revs increase with such painful slowness, it isnt even funny. At the stoplight, everyone leaves me behind .. I am easily the slowest to accelerate to 40mph or so.. It feels like my engine has 50hp instead of 250hp.

According to the dealer, The new Bosch distributor wires I bought could be sub-par and there could be arcing between the wires. The other thing he thinks might be wrong is that the small crack in the intake air hose (after the MAF) is causing the engine to run extremely lean and misfire. The third conjecture is that the injectors are fouled/dirty/inoperative. Now after spending all that money on caps/rotors/wires and the labor, the engine is running no better. There is absolutely NO power (I can barely make it up a hill). and engine is not at all smooth. I am thinking of debugging things in the following order

1. Fix the intake air-leak
2. Running a fuel-injector cleaner through the fuel system..
3. Cleaning the MAF.
3. Giving up on finding the problem myself.. and taking the car to a different mechanic and see if he can do any better..

Sigh.. Anything I can do better than going through the above steps..?

Och

iTrader: (3)

Did you experience the same problem BEFORE you took it to the dealer and had all of this work done? If the car was running better before, I would say demand them to check their work. Maybe they didnt plug the wires in correctly, and your car is running on less cylinders.

Fix the intake leak, use some silicone or duct tape.

Also try this - disconnect your MAF completely, and see how it drives. I just discovered a few days ago that my car is making GOABS more torque with the MAF disconnected, despite the check engine light.

karthick

I didnt get a chance to drive the car outside the parking lot.. And before I gave the car in, the car was stalling when in Neutral so I didnt get a chance to take it on a road.. so I dont know how much power it was making.. Yes. I did read the thread about disconnecting the MAF and I plan to try that today evening.. And I will try to fix the intake hose...

Oh I also plan to go to Autozone to see if I can find a cheap replacement hose .. Its the rubber part that connects the airbox and MAF

karthick

ok. So I tried two things today
1. used a whole bunch of duct tape to completely seal the air intake hose.. Then i disconnected the battery for a few minutes.. reconnected the battery... and tried to drive the car around.. The check-engine light came on as soon as I started the car.. and there was no improvement to the engine.. same sluggish performance and engine was far from smooth..
2. I then disconnected the MAF , disconnected the battery, reconnected the battery and started up the car.. Check engine light came on immediatly.. and same thing with the engine... no power.. and complete lack of smoothness...
I am not exactly sure what a bad misfire sounds like.. but perhaps this is what it is..

Oh another thing , when I started the car in the garage (The garage door was open). there was an overwhelming smell of petrol..my Audi S8 never used to smell like this...
I am stumped.. seems like I have to give it back to the Toyota dealer to try and figure it out...

Another thing to note is that due to some wiring problems.. the Traction control stays - off. I dont know if the engine problems are connected to the traction control.. but who knows.. ..

Och

iTrader: (3)

Well it seems like your car is running on less than 8 cylinders. You are smelling the gas that is being dumped into exaust from non firing cylinders because there's no spark to ignite it. It seems to me that your wiring, plugs, and/or distributor caps and rotors were not installed correctly. Sure the dealer is going to try to blame bosch wires, and while I too would much rather prefer OEM wires, I highly doubt that would be the problem. Bosch is a highly reputable brand and most of the time their stuff is as good as OEM.

I would start by taking off the distributor covers (quite a bit of work, as you will have to disassemble the whole intake and take off engine covers), and while the car is running try unplugging cylinder wires one by one, and see if it makes the car run different. Say if you unplug a wire and the engine starts stuttering more, that means that you unplugged a workin cylinder. And if you unplug a wire and it makes no difference, that means that cylinder wasnt firing to begin with.

Another thing to check is the coil. I know lexus has two distributors and two coils, so maybe if one coil is out completely, then the engine is running on only four cylinders, but I kind of doubt that, I dont think the engine would start at all on four cylinders.

And another thing to check of course would be the timing belt. If its off by a tooth, that will make your car run like total crap.

Of course it could also be a problem with fuel delivery - broken fuel line, faulty fuel pump, etc. Your best bet is probably to bring it to a decent diagnostics shop, and dont come back to that dealer, because if they want to charge you $300 to fix an intake leak, and blaming bosch wires for your problems, I say they are full of ****.

karthick

Ok. So I finally found out whats going on.
It turns out that there were two problems..
Problem 1 : The toyota dealership had plugged the spark plug wires in the wrong way, there were 2 cylinders whose wires were mixed up.. So the firing order of these cylinders was messed up. This does explain the fuel smell because if the spark plugs fired at the wrong time, then there is no way all the fuel was being burnt.. and it also explains the poor running of the engine..
2. The mass air flow sensor was bad .. so the remaining cylinders were running very lean , hence the very poor power...

The problems were diagnosed by this independent import shop that I found on the yellow pages.. They fixed both these issues (got a used MAF for $300 (I didnt want to wait, they are also available on ebay for $150).

Now the engine runs smooth like a top and there is a decent amount of power. From a standing start, I floored the accelerator and I spun the rear tires and traction control cut in ..
A Happy camper now..

Now I am seeing if I can get the toyota dealership to refund part of the labor costs I paid them to install the caps, rotos, plugs and wires... Damn toyota dealers.. maybe they did the bad wiring so I would come back to them to fix it..

bernard 96

Glad you fixed the problem.
I would have bet the fuel pump, because I replaced it on both my 91 ls and my 96 ls, both times after each car sat for 1 month. They both were an intermittent failure, and not total at once, just enough to strand me.
I replaced the second one myself, under the rear seat, quite easy, with the help of this board, and saved myself a thousand bucks.
Watch out for fuel pumps on these cars!