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Can you diagnose this? Please <3


Unclejake

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I used to live next door to a guy who worked in service for a well known Merc dealership. He used to do homers and I would get a look at how they were built. He summed it up that they were alot of quality, expensive parts but assembled poorly. I remember he had an early 90's sedan with a stuffed speedo. This was maybe 2001-2. The new part (complete cluster) was about 5K!!! It was probably a half of the cars value. I like em anyway.

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Forward of the muffler there is something that looks like a cat convertor. There is a probe in it.

FYI: that will most likely be the ERG - Exhaust, Gas Temp, Sensor. (a pyro meter). The ECU uses the value it sends to determine if the exhaust system is about to melt :P .. ok, .. it also tells the ecu the engine exhaust temps are really high, so the ECU makes corrections based on that. This might mean changes in timing, or changes in fuel (less or more), it depends on which method of reducing exhaust temps the ecu is programmed with.

If you suspect this sensor is a problem, earth it out. and plug the hole with a bolt. Normally this sensor is what I like to consider as non-critical (level 3, engine works fine without it). it can often be unplugged without effect.

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Those sensors are generally pretty reliable though aren't they? Dunno if they use K type like all the aftermarket deals, but there's not really anything that can go wrong with them without failing completely.

In saying that though, if the wiring to them is damaged or deteriorated it could effect the resistance and give a false temperature value.

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have spent a bit of time working on these things , from what you describe I would pull the coils could be as simple as moisture around them , have also seen a few coils arc out - pull the cover out (above plugs/coils) start engine you can hear or see the spark , also the enginebay wiring looms on these crap out (all the insulation falls off leaving bare wires) which causes some fun problems ! hope that helps

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Those sensors are generally pretty reliable though aren't they? Dunno if they use K type like all the aftermarket deals, but there's not really anything that can go wrong with them without failing completely.....

yes, reliable. Yes, they can fail completely.

I guess the point I was really trying to make was that they are in a state of decline from the moment of manufacture (the heated wire), obviously it's a time not use thing. So, eventually they might not fail completely but they can be in such a poor state that they are worse than not having one (the value it's sending is so wrong, so out of relationship with the air flow, the device is useless).

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(all the insulation falls off leaving bare wires)

Is this this awesome biodegradable insulation some auto manufactures thought was a good idea?

.. reminds me of the Vaxuhall chevette, everything on one side, wiring, exhaust, intake, alt, the lot. everything cooked.

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from what you describe I would pull the coils could be as simple as moisture around them
I waterblasted the engine on Monday and it ran fine that night - but it still had the full throttle miss. There was no visible moisture under the coil cover today, but I did not remove any coils. the car was used on Tuesday but not yesterday. The big problem started today.

I will run it without the coil cover on tomorrow night to see if there is any visibly arcing. I should have thought of that today. Thanks for the suggestion. It is a good one.

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Those sensors are generally pretty reliable though aren't they? Dunno if they use K type like all the aftermarket deals, but there's not really anything that can go wrong with them without failing completely.....

yes, reliable. Yes, they can fail completely.

I guess the point I was really trying to make was that they are in a state of decline from the moment of manufacture (the heated wire), obviously it's a time not use thing. So, eventually they might not fail completely but they can be in such a poor state that they are worse than not having one (the value it's sending is so wrong, so out of relationship with the air flow, the device is useless).

Sorry I was referring to the EGT sensor in that post, not the MAF.

Solution for the MAF issue is replace with a MAP sensor and Link ECU / 2ZZ

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OK. Here is the thing I cleaned. Google says it is an Air Temperature Sensor.

Does that mean I have to go find another sensor? I know what an Air Flow Meter looks like (a big thing the same diameter as the air intake hose after the air filter)... or does the MAF live inside the AFM?

mercedesbenze3201997int.jpg

this is the intake air temp sensor , they do crap out but wouldnt give the symptoms you have , the afm and maf sensor is the same thing mounted on intake pipe near air filter , can give your symptoms but unusual to break so soon

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Sorry I was referring to the EGT sensor in that post, not the MAF.

from memory it's just a metal or two, which react to heat and that changes resistance. I do remember a mate told me a while back when I said I wanted 10 of them (for a good reason), that I can pretty much just pick them up from a wreaker from various cars cos they all work the same, put out the same value, and never really die unless obviously well baked.

- just took his word for it. Never went to get them though, a wide band will work pretty well in most cases, unless you really want to dial it in on the lean side, then wide band + EGT in the first inch or so out from the head on each cylinder will allow for some 'to the wall' tuning. Better ways to do it now days though.

Solution for the MAF issue is replace with a MAP sensor and Link ECU / 2ZZ

cheaper than your mom ?

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Awesome. I will look harder at the coil packs tomorrow then. I should get time to buy some sparkplugs too.

Is there a trick to removal of the three coils? They looked like they just sit there, but there may have been a single, small, brass machine screw holding each one down

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Are they coil on plug? Most i have seen have a 10mm head bolt holding them on.

Argh...typed this on my phone then realised you saud you had pulled two plugs so cant be coil on plug.

Is it common to have both maf and afm? Assuming what uj says was replaced is an afm?

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Quite lol seeing the answers about MAF/AFM/trickery on OS.

Normally cars are MAF ("hotwire) or AFM, not both. I don't know anything about these cars though. If you have a large unit with a big flap inside it, you have an AFM. If it's just a black plastic tube with two wires poking through, MAF.

The sulfer smell has me poo'ed - perhaps the cat converter is blocked (happens all the time) which is not letting it breathe. This happens quite often ESPECIALLY on cars that have cats in/near the extractors as they block up and the exhaust build up causes mucho extra heat - which kills the plugs... which can go on to root your coils and leads.

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I haven't delt with these at all,

But if its wasted spark/coil on plug it'll probably look something like this.

wastedsparkcoilpack.png

That looks like the bastards.

Seriously: Cars should have one cylindrical coil that feeds a distributor with contact breaker points and also some carburetors. Gah!

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Awesome. I will look harder at the coil packs tomorrow then. I should get time to buy some sparkplugs too.

Is there a trick to removal of the three coils? They looked like they just sit there, but there may have been a single, small, brass machine screw holding each one down

just sitting there , central cover holds them down , good luck

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