Hi everyone, new to this platform, and new to this forum!

I'm having a few issues on a (new to me) 1999 e320 Wagon, with roughly 170K miles.

I have a P0301 teamed up with a P0201. Prior owner took it to an indy, that told him that the first cat was toast on the right side. So, he gutted it, and then gutted the second one in case it was blocked too. I have New ones on order.

I Changed plugs (OEM), swapped coils,(1&2) same codes return. Does run a bit better tho, but under powered. Sat for a 2 years from prior owner, new fuel put in.

What's next? Injector replace on Cyl 1,fuel filter replace, compression test?

Compression test will tell me if that cyl 1is toast of course. Old plugs looked alright, worn with average carbon, but not bad.

My guess is the misfire killed the catalytic converter, so I need to sort the misfire first before replacing the cats..


Any ideas / / threads I couldn't find / input appreciated!

 

1. Cats - there are TWO in line - front operating cat - and rear "can" cat. Not uncommon with time/age for the ceramic element in the front cat to "breakdown" causing "chunks and pieces" blown back to get caught in the screen in the rear "can" where there is a screen. Those chunks over time can cause back pressure problems.
The front cat can be checked running with a IR thermometer - as long as the exit/rear temp of the front cat is notably higher than the front/entrance temp to thet front cat - front cats are operation.
On the rear "cans" - the normal service thing is to cut them out - dump out the "chunks and pieces" - soak overnight in a large bucket of water/dishwasher detergent - airdry and reinstall. If your buddy "gutted"" the rear "can" - which means he removed the screen - that's not uncommon - front cats gutted means the front cat is not operational which will set off CEL's on the O2 sensors there.
Note breakdown of the front cats is accelerated by failed engine mounts - failed mounts cause added vibration sent back to the cat/exhaust system.
Front cat's are a bigger issue in California and some select states - can be replaced by generic bolt/weld-in's in other states

2. PO301/PO201 - in combination that's means misfire/injector - I would choose to replace fuel filter (Bosch - Mann - Hengst only) for $40-$50 and a few hose clamps - dose the tank with 1/2 bottle Stabil Marine Formula (Blue bottle) to start cleanup on the fuel/injection side. Fresh Mann air filter (only) for like $13 for the intake side. Quick MAF cleanup with 1/2 can MAF cleaner $9.
You mention plugs - the OE single platinum tips would be "thinned out" - but I go with your judgment on that - when I pull plugs "carbon" is not normally a look/fell issue on a W210 - so prior owner had some sh*tty fuel running thru there for a aweful long time.

Ultimately your MAF will age to out-of-spec - if you get there be cautious in replacing with genuine Bosch from reputable online vendor - and not get snagged by the China knockoff's.

3. Your single misfire is not the cause of "massively underpowered" - at 170K you need to be sensitive to the Transmission - as this is the key issue at your mileage. Do a "tranny reset" which takes about 2 minutes - search the forum for the procedure - which will reset the tranny to original aggressive defaults. This should give you refreshed "zoom"
Then you need to think hard about when you want to have proper service for the tranny - correct fluid - correct procedure - and replace tranny adapter plug with genuine MB/Mopar (only) - if tranny adapter plug has been leaking internally then Tranny Control Module (in engine compartment) needs to be pulled and use the remaining 1/2 can of MAF spray to flood clean both side of that board - and clean TCM connector port - let air dry and reinstall.
At 170K if your tranny gets proper service now - and about every 40K miles after) you will be able to go out past 300K if you want.

Keep the beat !

 

Thank you much, this is some great clear direction! I have a better plan of attack now.

One thing I forgot to mention is the air cleaner box seems to have been removed with quite some force in the past, and 2 of the 3 prongs (male) have broken off. As such there are holes in the bottom of the box. Curious if this could attribute to the issue? I picked up a replacement one from a local yard, but it came from a 2000, and is slightly smaller in the filter area. I'll grab a filter for that one and use it anyway, shouldn't be a problem I assume, it mounts right up. Only difference is the size of the filter.

The motor mounts appear to be in need of a change too. When the car is running rough due to the misfire, the engine shakes a bit more than what I would assume it should. I've seen far gone mounts before, and these are not there yet, but should be replaced anyway.

I picked up an installation on VM of WIS -ASRA & EPC, so I'm learning how to navigate that. I'm a BMW guy, so I'm used to just pulling up the Bentley! Any other sources you could suggest for repair / service manuals?

Again, thanks for the great input, I really appreciate it!

GS

 

On engine mounts - hydrostatic filled - Lemfoerder is OK brand about $50 each - China-made non-brands/quasi-brands frankly aren't worth sh*t.

On a single misfire like that 301/201 - frankly it would be hard to "feel" driving and it's the reason for the CEL alerts - what you are most likely "feeling" is engine vibration from failed mounts - and all long term W210 mounts fail.

You're best bet for DIY is to chase this forum, or the other forum (benzworld) , or YouTube... you will find directions for most "standard" maintenance/replacement items.

As a 1999 - you also need to check your Belt Tensioner - since original style was subject to failure at/about your mileage - replace with "new style" belt tensioner - one is called "innie" design - the other "outie" design check the forum and you will see this refers to the type of torx used on each style.

Ke

 

Perfect. Thanks again. I'm quite familiar with Lemforder, replaced the entire front end on my e34 M5 with their parts. I'll get some of them on order. Good stuff.

Cheers -

 

Thanks again for your help @fabbrisd1 . Funny story, and quite embarrassing tbh.. The PO ( a good friend of mine) took it to 2 separate indies. One of which is my BMW mechanic. He's worked on my 335, M5, and M3, with no issues. He's a Merc / BMW / Porsche / Mini shop.

Did the mounts - still an issue. Although still running rough the improvement was apparent.

Fuel filter - replaced.

Cleaned the **** out of the MAF.

Issue persisted.

Misfire, cyl 1, and a new injector code.

Started thinking about replacing injectors.

Didn't check wiring on injectors. Bought new injectors.

Went down the path of starting to replace injectors. Start with Cyl 1 by removing the plug.

Plug loosely falls off.

Was not plugged in.

Plug in.

#Win.

TLDR: Check all wiring for necessary items.

In all my years of being an 'enthusiast, I'm embarrassed to say it was a loose wire. TBH tho, the cat was jacked, and the mounts were effed.

THANKS again for your help, you still pointed me in the right direction.

It drives amazingly well, but I still need a new cat.

Excited to start down the path of enjoying this new platform!

=)

 

You mentioned about ordering cats. If so, where did you source?

 

Rear "cats" are actually a hollow drum with with a wire "grid" inside - these can be pulled - shaken out - soaked overnight in water/dishwasher-detergent - blown dry and reinstalled.

On "front cats" - measure with IR thermometer at engine operating temp - measure temp with IR thermometer - if Exit Temp at the rear of the cat isn't significantly higher than Entrance Temp at the front of the cat - that's the signal for front cat replacement.

If NOT California - then can replace front cat with generic weld-in replacement - if in California then replacement front cat MUST have CARB approved # on the cat - those replacements "new" or "refurbished" are a bit harder and most costly to source - google is your friend.