Never Rains But It Pours

[Liammr2]

Hi

Thanks to everyone's helpful suggestions my '96 got it's ignition issues fixed. Turned out to be a bad igniter module. Picked up the car, got less than 1/2 a mile down the road and the check engine light came on. U-turn and back she went - had to get a cap replaced. So, all the ignition issues sorted. Still has too much back pressure but they reckoned I could wait on that. Wasn't charged for the cap at all :-) - said that they should have checked better before they said done.

Well, it was not to be :-(. Less than a week later and the CEL was on again - and this time it was complaining about the cats. Being somewhat broke I've been looking for parts, not at the dealer prices ($1,100 per cat!!!!!).

Tonight I finally got the cats purchased and all four O2 sensors purchased. I didn't want to get any Universal ones - getting bolt in cats and plug in O2 sensors does mean that I paid more, but I'll save some on the installation. I got 2 x Eastern Catalytic converters for $120 plus shipping each, 2 x Denso 234-4169 O2 sensors (pre-cat) for $79 plus shipping each, and 2 x Denso 234-4603 O2 sensors for $105 each. I found a coupon giving 5% off from the last place, and got free shipping so they worked out at $100 and change each. I got Denso ones as AFAIK that's who makes the OEM sensors for Lexus.

Ouch. It took me a while to find places that had them all that cheap so if anyone wants to know where I got them from just message me.

Cheers, Liam

[jcrome04]

Sorry to hear! I've come to the conclusion that cars are nothing but money pits :) sooner or later they all devour it!

[eatingupblacktop]

Yeow!!! How does that song go? "If I didn't have bad luck, I'd have no luck at all!" Admire your persistence. Ya, it's always good to have sources. I'll pm you for them, thanks.

[jcrome04]

Speaking of songs... I don't know if any of you are country fans ( truly hope so!:) ) "Hard work never hurt nobody, but I'd rather be lucky" Pretty much the story of MY LIFE!!!!! Especially with vehicles! hahaha

Brad Johner - I'd Rather Be Lucky

Ps. It's a pretty catchy tune ;)

[stroker]

I guess you got a pretty good deal vs. buying from dealer..My 91 LS will probably be needing those replaced sometime soon (220,000 miles on originals). Where are the deals???? Thanks in advance for the info..Bob

Speaking of songs... I don't know if any of you are country fans ( truly hope so!:) ) "Hard work never hurt nobody, but I'd rather be lucky" Pretty much the story of MY LIFE!!!!! Especially with vehicles! hahaha

Brad Johner - I'd Rather Be Lucky

Ps. It's a pretty catchy tune ;)

[wwest]

Hi

Thanks to everyone's helpful suggestions my '96 got it's ignition issues fixed. Turned out to be a bad igniter module. Picked up the car, got less than 1/2 a mile down the road and the check engine light came on. U-turn and back she went - had to get a cap replaced. So, all the ignition issues sorted. Still has too much back pressure but they reckoned I could wait on that. Wasn't charged for the cap at all :-) - said that they should have checked better before they said done.

Well, it was not to be :-(. Less than a week later and the CEL was on again - and this time it was complaining about the cats. Being somewhat broke I've been looking for parts, not at the dealer prices ($1,100 per cat!!!!!).

Tonight I finally got the cats purchased and all four O2 sensors purchased. I didn't want to get any Universal ones - getting bolt in cats and plug in O2 sensors does mean that I paid more, but I'll save some on the installation. I got 2 x Eastern Catalytic converters for $120 plus shipping each, 2 x Denso 234-4169 O2 sensors (pre-cat) for $79 plus shipping each, and 2 x Denso 234-4603 O2 sensors for $105 each. I found a coupon giving 5% off from the last place, and got free shipping so they worked out at $100 and change each. I got Denso ones as AFAIK that's who makes the OEM sensors for Lexus.

Ouch. It took me a while to find places that had them all that cheap so if anyone wants to know where I got them from just message me.

Cheers, Liam

My troubleshooting technique, ~50 years in developement, would have meant purchasing/replacing the rear oxygen sensors first, then if "cat" fault still indicated I would replace the cat. I would be surprised if the front oxygen sensors need to be replaced at all.

The rear oxygen sensors are used to verify the operational functionality of the catalyst.

The front oxygen sensors are used to control the A/F mixture during idle or cruising, the MAF/IAT sensors take over that task when the engine is under acceleration loading, mixture is being enriched (~12:1) beyond the measurement capability of the front oxygen sensors.

$120 for catalytic converters...??

Are you sure those aren't just straight (bypass) pipes?

Too much back pressure..??

Exhaust back pressure..??

That would most likely mean the internal "honeycomb" structure containing the catalyst has broken down and is partially blocking the exhaust flow. Would generally mean the catalytic converter exterior will glow cherry red with heat at night after a ~20 minute hard run.

[Liammr2]

My troubleshooting technique, ~50 years in developement, would have meant purchasing/replacing the rear oxygen sensors first, then if "cat" fault still indicated I would replace the cat. I would be surprised if the front oxygen sensors need to be replaced at all.

The rear oxygen sensors are used to verify the operational functionality of the catalyst.

The front oxygen sensors are used to control the A/F mixture during idle or cruising, the MAF/IAT sensors take over that task when the engine is under acceleration loading, mixture is being enriched (~12:1) beyond the measurement capability of the front oxygen sensors.

$120 for catalytic converters...??

Are you sure those aren't just straight (bypass) pipes?

Too much back pressure..??

Exhaust back pressure..??

That would most likely mean the internal "honeycomb" structure containing the catalyst has broken down and is partially blocking the exhaust flow. Would generally mean the catalytic converter exterior will glow cherry red with heat at night after a ~20 minute hard run.

Yeah, I'm sure they aren't straight pipes :-). I looked long and hard to get ones that cheap. Indeed, too much back pressure, and the cat gets very hot - they saw that when fixing the ignition problem. I would have started with the back O2 sensors as you say except that I am getting a garage to do the work - so it works out less hassle and costly to have all the relevant bits swap in one go while they are under there.

Cheers, Liam

[eatingupblacktop]

If the cats are getting really hot with normal driving, I would get them to check the fuel trims. Really hot cats indicate unburnt fuel coming down the pipes, which could point back to ignition issue (coils?).