How is everyone ? Good i Hope.. I think this site is the BEST for advice.
I have a problem...not major I hope.
I have had my check engine light to come on and it gave me a code about Catylyic Effeiciency. The mechanic said not to worry if the light went out but it was a problem with the convertor.
Sure enough the light went out and everything was fine... Soon i heard a rattling and they told me that it could be the convertor.
The rattling started getting real bad last night so i called an Exhaust shop this morning and they said they could remove it and replace it with pipes for $100.
I was gonna do that, but on the way over there the car started hesitating and stuttering, the check engine light started flashing.
Got to the shop and they said it was the rear convertor and they could replace them with pipes because we don't need inspections in my area.
he took it off and then told me that it was fine so he welded it back.
We started the car and NO MORE RATTLING but now the car is still hesitating as if it doesn't want to go.
In drive it is kind of sluggish. We tried to run a scan but his scanner didn't work and the other one was locked up for the day so I just left the car there.
Any suggestions ? I'm thinking spark plugs or something , but why is the rattling gone now and what was it in the first place. I'm assuming it had something to do with the hesitating.
hey Sean....what's up?.....sounds like bad cat(s), did he check both of the rear ones.... also check all four o2 sensors....the rattling will continue until the pieces get broken up enough to get passed on down and eventually out (happened to me, two golf ball size innards of the cat - cat had completely gutted itself - ended up at the exhaust inlet!)....however, if the pieces plug up your cat (or any other part of the exhaust system) you will end up with misfire issues and eventually limp mode until resolved!...x2 on replacing rears with pipes or hollowed out cats...will pass inspection since o2 sensors are before and after front cats....you can also perform back pressure tests at the o2 sensors....good luck!
He only took one off and once he saw it wasn't bad he welded it back on.
He tapped the other one and said that it seemed fine so never took it off.
So what you are saying that there is a possibility that when he took it off the debris could have been blown out after he started the car and now is not there to rattle anymore ?
Also when you say misfire, are you suggesting that i probably just need to change my spark plugs ? I have my car there now and I would like to suggest this to him since this is something that you have been through already.
....he shoulda used a mechanics stethescope to pinpoint your issue....once cats break down, they disintegrate in random ways, but mostly it's like tumbling cement in a cement truck (crude example), eventually smooth dust!....and depending which end he cut...there would be more damage on the engine side, where it gets hottest....mine stopped rattling because (two golf ball size) pieces, (all that was left of one cat!) had worked their way out, leaving the cat completely hollow!...
....you can change plugs if you think they are old/bad (oe is rated at 100-150k)...but , yes any carbon buildup in the exhaust can mean buildup elsewhere up line, including plugs....however, some seafoam may take care of your buildup issue, but you need to find the cause too....good luck!
I just talked to him and he said that he ran the scan and it does still say catalyic effeciency and he said that , it means there could be a problem with the front converter.
I don't know what this means....can i still bypass that one ?
also he did say i had a misfire in 3 cylnders....He is suggesting that i do all the filters , and everything in a full tune up..
I know i need to get that done anyway, but i just need to get going in my car so that i can get to work...I'll do the rest when i get paid.
What can i do to get by TODAY ? Just replace the spark plugs and keep moving ?
Or what do you suggest....I know i'm riding in a Benz but i'm on a Hyundai Budget this month due to my business not doing so well this month.
i would just change the plugs and hopefully no bad coils. i think your engine takes cheap copper plugs, so no need to get the expensive double platinums. worry about oil/filter change later when you have more money, but don't wait too long if they are way overdue. at least check the oil level and visually check the air filter to make sure is not extremely dirty.
hey bud....changing your plugs would be a good first step for a tune up, and it may deal with your "catalytic efficiency" issue! .....remove the misfiring ones and inspect their condition.....while at it....x2 on inspecting/cleaning/replacing air filter, maf sensor, vacuum lines, fuel components, etc...
btw....there are two in line cats on each exhaust bank, with two o2 sensors on each bank, one before the front cats and one after the front cats (i.e. before the rear cats).....he can check the back pressure of the exhaust bank at any o2 sensor point...where the pressure is the highest is where the blockage is....or if he has an IR gun, he can measure the temp of each cat and the hottest would be the culprit....mind you the front ones are a bit harder to work on!.....have him figure out your cat issue, if any, while there!.....if you rev engine to the cat's resonant frequency (~1500-1800rpm, or driving in reverse up a hill), you may be able to tell the difference between which one is rattling, if it does....kinda crude but works on majority....good luck, man!
They have replaced all spark plugs. and say that The front cat converter is bad.
They are suggesting that i replace both at $1005 a piece. Not feasible for me.
They said that after changing plugs we have the same problem. but after they drop the pipes it runs fine.
A quick fix was to just bypass it and put a pipe in because the others in the back are working fine. But he said that it may do something to my computer but doesn't know
Can this be a quick fix so that i can get back on the road and make some money to do it the normal way ?
Also they told me that I have to go to the dealer because non of his suppliers have the part. He said that i have aftermarket stuff under there now.
Also he asked if i wanted an Oxegyn Simulator... now i'm clueless...
hey man....what?....just the front cats...$1000 a piece....?!@??@#??%!?%@?^.... are you kidding me?!?!....i know that they are a bit more work, but really!.....maybe ~$500 each, but even that is too much!....
....after market cats are ~$65-$150 each, install ~$50 each....you can get a whole bank (all piping from exhaust manifold to resonator including front and back cats) at ~$1700 each, at the dealer!.... you can even call up a few dealers and ask about refurbished cats, should be ~$500-$700 with core exchange - the whole bank!....
....you can do any configuration you want as long as there is a cat, o2 sensor and muffler somewhere all in line.....however, dealing with the computer and 4 x o2 sensors and it's programming is another issue....technically, you can delete the rear cats, as you don't really need them (it would be good to replace with a cross over to compensate for resonance, but not necessarily, straight pipes would do just fine too), and resonator (will give you some rumble and growl) replace the muffler with high flow one.....see example pics...
...oxygen simulator???? don't really know. why? as a band aid?
When you say leave the fronts the way they are, i see what you mean
but the fronts are what the shop is telling me is bad , and when we leave it that way the car runs sluggish because it is bad, but after dropping the pipe that connects the converter it runs good again. That's why he said he should just run a pipe in the place of the converter.
He said that since i still had the backs , i would still have a quiet ride.
This would be a temporary fix until i order the setup you just showed me.
Would this be a good idea ? Well this morning he called and i told him to go ahead and do it.
i hope i made a good decision.. i need my car for work.. i've been off since Monday because of this...lol
...replacing a front cat with a straight pipe would be fine....however, there may be an issue with a cel coming on because of the o2 sensors front and aft of the front cats, the computer is expecting to see a difference between them?...won't know til you try, maybe it'll run real good, unwittingly, eh!...good luck!
the cel will come on for sure after removing the front cat, that's why your mechanic is telling to get an oxygen sensor simulator to fool the car's computer. personally i wouldn't keep this setup for too long. first of all it is illegal, but that wouldn't be the only concern. i'm not sure if your engine is designed to run better with the back pressure, or it might run too lean or rich. for something temporary until you save a few $ it's probably fine, but you might want to get an aftermarket cat. the oxygen simulator is probably gonna be more expensive than an aftermarket cat.
I have a 97 E - 420 too, How many miles did you have on yours before the cats went out?
160,000 miles, runs fine and I'm curious about something obvious, to my knowledge each 4 cylinder have their own Cat
But, when I look at pictures of Bolt-on direct replacement it has 2 boxes welded on the pipe, one immediately below the manifold,
and the other one under the trunk.
So I asked, does each bank actually have 2 Cats?
and this means my car has four catalytics? !!
or is the one in the rear just a silencer/muffler?
yes, each bank has two cats and two oxygen sensors so a total of 4 cats. Actually a pretty common system for many cars.
Also, at 170K my DS front cat failed and I replaced the DS assembly (both cats) with an OEM from the dealer. $560. took me a little over an hour to remove and replace the cat once I got it up on my lift. actually a very very easy job. MB uses bolts that don't rust and seize for the front and back, and the assy is an easy remove and replace.
If you go to a dealer ask for a "remanufactured" cat assy, not a new one. What you will get will either be a new or remanufactured, depending on what they have in stock.
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