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AndyLowe

Pull Up A Chair And Learn From My Mistake

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I tell you all this in hopes you avoid what I learned the hard way, and because it is how we all grow our knowledge.

The type of car this occurred on was a ES300 V6, but it still applies to this Forum as it is applicable to both.

Back in April, I bought an Autozone Duralast Timing Belt, for my daughter's car. She would get her License in late Sept, but the car was worth buying as it needed repairs and we had time to repair long before she would start driving the car in Oct. I had replaced the forward Head Gasket, Water Pump, Thermostat and Timing Belt. I always purchase genuine Toyota Thermostats, but often go aftermarket on the other items listed.

When October came along, it was time to get the Emission Inspection and even though the car ran well, it failed for excessive HydroCarbons and Carbon Monoxide.

In our state, we get one free re-test, and so I knew I must truly solve the issue.

I came home, popped the hood open and applied my volt meter to the Diagnostic Connector found on EVERY Lexus/Toyota engine, and with DC Volts selected, observed the O21 and O22 (Oxygen Sensor 1, 2) readings.

O21 was porpousing quickly between .2v to .8v with engine at idle, at correct normal temperature. This is correct.

O22 was always below .5v, and would change slightly from .3v to .4v and very rarely reach .5v.

To determine which O2 on the engine was O22, I watched my meter while disconnecting the O2 closest to the front bumper and my meter went to zero volts. Great! It's the easy access O2!

Any readings below .5v is Lean. Lean Mixture is Low Voltage

Above .5v is rich

The O2 Sensor was telling the ECU (Computer) that the exhaust stream was Lean and I then looked for an Air Leak on the Intake Manifold which I had installed new gaskets on, back in April. Finding none, I used some brake clean aerosol and gingerly sprayed around the edges of the Intake manifold mating surfaces, seeking to find if the engine RPM sped up or the volt meter would now rise above the .3v - .4v range it doggedly remained in.

No change with adding a rich, flammable vapor near the Intake gaskets and no vacuum lines broken or missing.

Next I watched the volt meter and disconnected one electrical connector at a time, from the three related Fuel Injectors for the 3 cylinders reporting to this 02.

The engine immediately responded by running rough as I removed one injector at a time and the mixture on the voltmeter would go even more lean; .2v, etc.

Reasoning that the O2 may be damaged from back when the Head Gasket failed and steam had its way, I decided to replace the O2 sensor and went to Oreilly Auto Parts. They had a Bosch universal, for $19.99 and when I got home to change it, I found the original O2 was not the type that unscrews from it's little plate steel mount. (I broke mine trying to unscrew it and learned it's welded in!).

Back at Oreilly's I returned the universal, and bought the $64.99 Exact Fit Bosch, and that was only due to a price match from Autozone. (Oreilly's price was normally $84.99 and they are close by).

With the new Exact Fit Bosch in place I now had, guess what?

.3v to .4v

All along this troubleshooting, I was remembering what I had seen back in April:

When I reassembled the engine back then, I remember fighting to get all three timing belt marks to line up with the factory marks, and was ALWAYS unable to get this forward most cylinder head Cam Gear timing mark to be perfectly in line with it's rear mark!

I reasoned that perhaps the Crank Shaft Gear might be one tooth "off" and this would cause the Cam Gear to be "off" a half of a tooth, because of the "two Crank revolutions, to one Cam revolution" ratio. I tried marking them all with White Out, taking the belt off, shifting the belt one tooth on the Crank Gear and reinstalling.

This only moved the problem on the upper cam gear to the OTHER side of the mark it was supposed to line up with.

Back in April, I went ahead and put it all together, and it ran good, so I waited till October; when my daughter would start driving it.

I enlisted my 14 year old son at this point, went to Oreilly's and bought a GATES Timing Belt. I have always loved Gates Products as they are a PERFECT FIT, and their Timing Belts come with the three white lines clearly marked "Left Cam, Right Cam, Crank" and they ALWAYS line up perfectly.

We took out the Autozone Duralast Belt, put in the Gates Timing Belt and WALLAH!~! It lined up perfectly.

We re-assembled everything, hooked up our volt meter and watched as the O2 sensor came to life. (They are thermocouples and need time to warm up before they produce reliable signal voltage)

When it was warm, the new O2 was porpousing rapidly between .2v and .8v and my son and I shook hands in renewed confidence!

We drove over and had the Emission Re Tested and it passed very quickly. (It's a 1992 ES300, with 82,500 miles; clean as a pin!)

It was mechanical valve timing that was off.

That's all it was.

I never needed a new $84.99 O2 Sensor, but it doesn't hurt to replace them as this was 18 years old.

My lesson to all of you is to make sure your Cam and Crank Timing Marks ALL line up perfectly.

Don't re-assemble an engine that is not lined up perfectly. It will run, but it won't run right.

I'm truly grateful for the whole problem because of the lesson it taught my 14 year old son; sometimes you have to make absolutely sure you have done something perfect. Accuracy matters and is crucial sometimes in life. Strive for it, demand it and earn it.

It was a great moment watching my daughter drive off in her car that she has been waiting 7 months for. She did not know it would be ready, but had seen us working on it for several days. She was beaming and I too was thankful for what my 14 year old son had gained.

Andy

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i work for autozone and everything we sell is made in china; in about 10 yrs when u walk in the door it will look like a walmart; dont come to us for parts; they should be ashamed to call them selves an autoparts store; we do sell alot of hard parts but i think that will change and all they will sell is overpriced oil and filters along with a few tools and alot of carwash/wax and tireshine (usual diy detailing)

But I will say we have the greatest return policy and gaurentees in the industry. lifetime breaks are great; wear them and and you get new brakes; as for the alternators water pumps starters and everything else that has a lifetime warrenty; i look at it like this; I heard the starte on my 90 ls400 is under the intake manifold; do i really want to tear all that apart put in a made in china starter that goes bad in 2 yrs and hey yea grat i get a free starter but hey yeah i got to tear into that motor again to replace the starter.

That being said I shop there because of the warrenties and the employee discount; Ive never heard of any one bring back a timing belt; but i believe you 100%

Sorry for your troubles but you know what they say...payless get less

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i work for autozone and everything we sell is made in china; in about 10 yrs when u walk in the door it will look like a walmart; dont come to us for parts; they should be ashamed to call them selves an autoparts store; we do sell alot of hard parts but i think that will change and all they will sell is overpriced oil and filters along with a few tools and alot of carwash/wax and tireshine (usual diy detailing)

But I will say we have the greatest return policy and gaurentees in the industry. lifetime breaks are great; wear them and and you get new brakes; as for the alternators water pumps starters and everything else that has a lifetime warrenty; i look at it like this; I heard the starte on my 90 ls400 is under the intake manifold; do i really want to tear all that apart put in a made in china starter that goes bad in 2 yrs and hey yea grat i get a free starter but hey yeah i got to tear into that motor again to replace the starter.

That being said I shop there because of the warrenties and the employee discount; Ive never heard of any one bring back a timing belt; but i believe you 100%

Sorry for your troubles but you know what they say...payless get less

You should quit your job. Your employer provides you the income to live your life. You don't seem very grateful.

As for generic comments that basically state "made in china"=bad, "made in china"=poor quality then you are highly mis informed. Sure there are some questionable items that come out of china but most items manufactured today have components and assemblies coming from China. It is the largest manufacturing country in the world. Take a look at the label on virtually every consumer electronics item you own. 90% are made in China.

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i work for autozone and everything we sell is made in china; in about 10 yrs when u walk in the door it will look like a walmart; dont come to us for parts; they should be ashamed to call them selves an autoparts store; we do sell alot of hard parts but i think that will change and all they will sell is overpriced oil and filters along with a few tools and alot of carwash/wax and tireshine (usual diy detailing)

But I will say we have the greatest return policy and gaurentees in the industry. lifetime breaks are great; wear them and and you get new brakes; as for the alternators water pumps starters and everything else that has a lifetime warrenty; i look at it like this; I heard the starte on my 90 ls400 is under the intake manifold; do i really want to tear all that apart put in a made in china starter that goes bad in 2 yrs and hey yea grat i get a free starter but hey yeah i got to tear into that motor again to replace the starter.

That being said I shop there because of the warrenties and the employee discount; Ive never heard of any one bring back a timing belt; but i believe you 100%

Sorry for your troubles but you know what they say...payless get less

You should quit your job. Your employer provides you the income to live your life. You don't seem very grateful.

As for generic comments that basically state "made in china"=bad, "made in china"=poor quality then you are highly mis informed. Sure there are some questionable items that come out of china but most items manufactured today have components and assemblies coming from China. It is the largest manufacturing country in the world. Take a look at the label on virtually every consumer electronics item you own. 90% are made in China.

you should see the the returns we get; no they dont provide for me; I work there p/t untill i get a to work at a real parts store. But Ill tell you rhis Duralast batteries are #1 on consumer reports although Id rather have an interstae or a diehard. but I gotta shop where i get the discount

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The timing belt story was good and I learned some things. I fought with one of them on a Ford Cortina one time. Regarding the Autozone inside story, I also appreciate that. Always nice to have information no matter how distastful you may find it. I rarely use Autozone but they do have a very nice tool lend policy. I have used them a couple of times for that. I usually go to Advance as it is close. I would guess their parts are comparable to Autozone. NAPA is probably one of the best.

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