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1995 c220
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Discussion Starter #1
Hi All,
I got my w202 as my "owned" first car after college. I have had the car for about 15 months and it has served me well. The car developed an issue where it would idle rough after I had driven it at highway speeds. So basically, the idle was fine if I was just driving in stop and go / city traffic (regardless of cold start or not). But after existing a highway the car would idle rough, IMPORTANT NOTE: the problem would go away as soon as I restart the car. So I would just re start the car on the first stop sign or red signal I encountered after getting of the highway and everything would be fine again.

Last month I moved from the east coast to Colorado on my w202. It worked as expected but before getting on the highway on the second day of my journey I realized that the car was idling rough all the time (cold start, operating temp, highway or no highway). After the journey restarting the car would sometimes get the car to idle right but now no matter what I do the idle is always bad and eventually the car stalls if I don't keep my foot on the pedal. It still drives great on the highway or at any speed really.

I checked the loop from the air filter to the throttle body and there are no leaks. In my search I found that I should test my MAF by disconnecting it and that the idle should fix itself or at-least show some change. So, I disconnected the MAF, took it for a spin and it did nothing to the car, the idle was still bad, the acceleration didn't feel any different, basically it drove like nothing was changed. I am planning on changing the MAF just for good measure, along with spark plugs and spark plug wires (because I don't know what else to do or check for)

The only light on the cluster is the SRS light and low windsheild washer fluid light. (Never cleared any codes during my ownership) Any help is highly appreciated.
 

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1995 c220
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13 Posts
Discussion Starter #2 (Edited)
Just adding the work I did on the car for some context:
Got the car from an auction because it had very little millage on it ~ 62,000.
The A/C blower didn't work, there was a horrendous amount of break rotor wear. The whole car would vibrate while breaking, the radio was broken. Water came in from the front passenger side foot rest area and the car was last inspected for NJ in 2014 I bought it in 2019. There were small specs of white paint all over the body (the car is blue).

Replaced the blower motor, got a new cheap looking BT radio set, changed all four rotors and accompanying break pads. The water came in because of clogged drain pipes, dead leafs and dirt had accumulated. Changed the spark plugs, air filter, cabin air filter, transmission oil, power steering oil, and did a break fluid flush. Detailed the car inside and out got rid of the white paint dots covering the body of the car. Finally after scrapping every dollar got cheap but new tires on the car (had just graduated college :D )
Changed the engine oil and filter every 5k miles since.
Drove it about 20k miles in the 15 months of ownership very proud of how it looks and drives now compared to when I got it.

Edit: the Cruise Control didn't work was able to fix the issue because of this forum, basically just needed a soldering iron and the CC module.
 

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W163 and General M Gremlin
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4,650 Posts
Welcome to BW DevOps,
Have you scanned for any saved error codes. If not, do so and post here.
Idling issue could be a number of issues.
For the simple things first.
When was the last time you changed the fuel filter?
Check the fuel pressure at start up and at idle.
What grade/quality gas are you using? (I dont recall the recommended grade. Check the Fuel Cap door.)
I would also recommend you do simple cat check with a temp gun. (fore and aft of the cat)
I'd also recommend you use a bottle of berryman, B12 - 1/3 of the bottle thru the BB vacuum intake (have a 2nd body keep the reves up to at least 2K when doing this) and then the rest into the gas tank. Note: you'll get alot of white smoke out the exhaust so be forewarned.
Report back.
 

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1995 c220
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13 Posts
Discussion Starter #4
Welcome to BW DevOps,
Have you scanned for any saved error codes. If not, do so and post here.
Idling issue could be a number of issues.
For the simple things first.
When was the last time you changed the fuel filter?
Check the fuel pressure at start up and at idle.
What grade/quality gas are you using? (I dont recall the recommended grade. Check the Fuel Cap door.)
I would also recommend you do simple cat check with a temp gun. (fore and aft of the cat)
I'd also recommend you use a bottle of berryman, B12 - 1/3 of the bottle thru the BB vacuum intake (have a 2nd body keep the reves up to at least 2K when doing this) and then the rest into the gas tank. Note: you'll get alot of white smoke out the exhaust so be forewarned.
Report back.
Thank you khmer2 it's a pleasure :)
I did do a scan before the long trip and at that time there were no codes on it.
I never changed the fuel filter, my brother also said I should do that first but if its the oil filter shouldn't the car have troubles going to higher revs?

Will do another OBD-II scan and my first fuel pressure check and post the results here.
Should I do the temp gun and B12 first before the MAF and spark plug wires replacement?
And where does the fuel filter lie on the priority?

I just want to go from the smaller things to the bigger/ expensive stuff.
 

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W163 and General M Gremlin
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4,650 Posts
Thank you khmer2 it's a pleasure :)
I did do a scan before the long trip and at that time there were no codes on it.
I never changed the fuel filter, my brother also said I should do that first but if its the oil filter shouldn't the car have troubles going to higher revs?

Will do another OBD-II scan and my first fuel pressure check and post the results here.
Should I do the temp gun and B12 first before the MAF and spark plug wires replacement?
And where does the fuel filter lie on the priority?

I just want to go from the smaller things to the bigger/ expensive stuff.
You saw no change with the MAF disconnected. It could very well be the MAF sensor itself that is not reading correctly. Try some CRC maf cleaner first. Note: it's only the sensor in the MAF that needs to be replaced, not the housing if it's still good. Maybe your scanner can read live feeds of the STFT and LTFTs? - this would be good to see.
Temp gun chexk is always a simple test so long as you have a temp gun. I always keep it in the check list as it's a simple and fast test to check the cats. Cats issues can be tricky too as it could be on the verge of an error code and still not register. In your case, your revs are high and you have no sluggish runs so it's not an really an issue - just a quick check.

You can leave the B12 to last, (just some love for the w202)

No real order to follow but for the SP wires, if you have a multimeter ====>

So scan first to read the STFT and LTFTs, then MAF cleaning and or sensor replacement.

Temp gun cat test, if you can borrow one but not necessary.

Lastly, you've said you checked for vacuum leaks and found none. Are you absolutely sure?
Otherwise, smoke test with a DIY smoker. (easy and cheap to build one)
 

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1995 c220
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13 Posts
Discussion Starter #6
After moving I really have no tools, the only reason I was able to work on the car before was my very nice neighbor who let me use a lift and tools in their garage after hours as long as I left everything the way I found it.
That being said I am fully committed to getting enough tools so I can work on my car / cars (soon hopefully). Is there a specific OBD-II tool that people might have experience with and found good/better than others. I am willing to buy a mid ranged scanner if it really does provide benefits over the very basic one, not sure if a very high end (professional grade) scanner would provide me with any real benefits over a basic/mid-range one. The only one I used was the very basic one used by the garage's mechanic to clear codes.
I'm sure you might have guessed it by now I am somewhat of a nube, thank you khomer2 for your input.

I forgot to mention, I use premium 91/93 (depending on the gas station), I have tried the regular (87) and Plus (89) once or twice in the very beginning of my ownership but since I am no longer a fresh college graduate, premium is what my C220 gets.

P.S I am getting a multi-meter anyways because I need it for my other projects + tools + soldering iron etc, I looked online and the heat gun is not expensive so I am adding that to the list. I am planning on adding a Fuel pump and Vacuum tester to the list too, let me know if anyone else has found it useful.
 

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W163 and General M Gremlin
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4,650 Posts
Sounds like you had a nice arrangment you had with your good past neighbor. :)

These w202s are aging: I recommend you make yourself a DIY smoke machine - you can make one fo under $20 worth of parts. Vacuum lines and connectors are brittle and leaks can get hard to find visually.
As for a scanner, try borrowing one; you have the option I believe of borrowing them and other tools from your many parts shops south of the 49th. Check around.

 

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Registered
1997 W202 C220
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202 Posts
You saw no change with the MAF disconnected. It could very well be the MAF sensor itself that is not reading correctly. Try some CRC maf cleaner first. Note: it's only the sensor in the MAF that needs to be replaced, not the housing if it's still good. Maybe your scanner can read live feeds of the STFT and LTFTs? - this would be good to see.
Temp gun chexk is always a simple test so long as you have a temp gun. I always keep it in the check list as it's a simple and fast test to check the cats. Cats issues can be tricky too as it could be on the verge of an error code and still not register. In your case, your revs are high and you have no sluggish runs so it's not an really an issue - just a quick check.

You can leave the B12 to last, (just some love for the w202)

No real order to follow but for the SP wires, if you have a multimeter ====>

So scan first to read the STFT and LTFTs, then MAF cleaning and or sensor replacement.

Temp gun cat test, if you can borrow one but not necessary.

Lastly, you've said you checked for vacuum leaks and found none. Are you absolutely sure?
Otherwise, smoke test with a DIY smoker. (easy and cheap to build one)
I have been trying to look around where I can purchase the sensor in the MAF but cannot seem to find one even in Ebay. Do you mind giving me a hint? Is the sensor also a Bosch? What would be the part number? The part number I see in the housing of my MAF is 0280217100, would it be the same if we look for the sensor only?
 

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W163 and General M Gremlin
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4,650 Posts
vin#?
 

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Registered
1995 c220
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13 Posts
Discussion Starter #10
Update: Cleaned the MAF and drove the car a little, the check engine light came on for the first time.
Will be spending some time on the car later this month, till then it's time to gather tools/replacements :D
Thank you guys, this gave me quite a bit to work with, I will go over the car in detail and post my findings here.
@khomer2 I will post all the readings/findings here along with the process I follow. TY!!
 

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W163 and General M Gremlin
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4,650 Posts
Is this question for me? Anyway, my VIN = WDB2020225F391262
jake,
According to epc, seems that the maf sensor itself is not available, only the whole unit with the sensor.
Strange, as Ive purchased the sensors only w/o the maf casing.
You should cheek with your suppliers if they do sell only the sensor unit. (cheaper than the whole)

Part #5 with your vin#
 

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1995 c220
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13 Posts
Discussion Starter #13
I checked online before ordering mine, the options of just the sensor were weird. They were either 20,30 $ or 350$ and the Bosch OM unit with the casting is under 200$ so might as well get the real thing.
@khomer2 I can't seem to find the factory spec resistance for the spark plug wires, so should I just assume if all four wires are close to each other they are good?

Plus, I noticed a not so good pattern with my spark plugs, the farther away you go from the front of the car the spark plugs got better,
The first one I pulled out (the front most spark plug) definitely had alot of carbon on it and the ground terminal was a little eroded making a small concave shape where the spark landed.
The middle two were okay I guess were better than the first one but still some carbon was there, the ground terminal was barely eroded ( you had to look very hard to find a very tiny dent)
The one closest to the fire wall came out the clean just the clean brown color change evenly throughout the plug.

The one in the front is the only one where you can see the white base getting brown with the heat too. Not sure if this means something or it's because of the coolent flow in the engine.
 

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1997 W202 C220
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202 Posts
Khomer, I wondered why the part number on my MAF is different with what you sent, any idea? Does that mean that I can use either of the two part numbers as referral, thus, interchangeable?
Suppliers here sell the whole MAF casing that is why I was hoping to source out a cheaper one when the need arises or as a spare for the moment.
By the way, how do you get into EPC? It is convenient to have such source to check on part numbers.

jake,
According to epc, seems that the maf sensor itself is not available, only the whole unit with the sensor.
Strange, as Ive purchased the sensors only w/o the maf casing.
You should cheek with your suppliers if they do sell only the sensor unit. (cheaper than the whole)

Part #5 with your vin#
 

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W163 and General M Gremlin
Joined
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4,650 Posts
I checked online before ordering mine, the options of just the sensor were weird. They were either 20,30 $ or 350$ and the Bosch OM unit with the casting is under 200$ so might as well get the real thing.
@khomer2 I can't seem to find the factory spec resistance for the spark plug wires, so should I just assume if all four wires are close to each other they are good?

Plus, I noticed a not so good pattern with my spark plugs, the farther away you go from the front of the car the spark plugs got better,
The first one I pulled out (the front most spark plug) definitely had alot of carbon on it and the ground terminal was a little eroded making a small concave shape where the spark landed.
The middle two were okay I guess were better than the first one but still some carbon was there, the ground terminal was barely eroded ( you had to look very hard to find a very tiny dent)
The one closest to the fire wall came out the clean just the clean brown color change evenly throughout the plug.

The one in the front is the only one where you can see the white base getting brown with the heat too. Not sure if this means something or it's because of the coolent flow in the engine.
Checked you coils?

Check your plugs, the may need to be replaced - copper with no resistance in them.
I use the same for my sons w202.

Wires? - generic or oem, your choice - oem more $$$
I've had good results with karlyn brand - used them on a couple of neighbors c-class cars to keep their costs down.
 

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W163 and General M Gremlin
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4,650 Posts
Khomer, I wondered why the part number on my MAF is different with what you sent, any idea? Does that mean that I can use either of the two part numbers as referral, thus, interchangeable?
Suppliers here sell the whole MAF casing that is why I was hoping to source out a cheaper one when the need arises or as a spare for the moment.
By the way, how do you get into EPC? It is convenient to have such source to check on part numbers.
What part # you getting? post here.
According to your vin# you provided, post #12 link

EPCs ===> I use several sources, here's a few.
mbepc.net but it seems to have issues now on access (not sure why)
catcar.info
mbpartscenter.com
ilcats.ru
 

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1997 W202 C220
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From the post number 12 link, the MAF sensor part number is A0000940048. The part number I see in my Bosch body is 0280217100. I stand corrected, maybe the difference in part number is because in your link, it is only the MAF sensor's part number and in my Bosch part number, it is for the whole assembly.
Is the MAF sensor which you purchased also a Bosch? If I check eBay, it seems the sensors are available but they are not Bosch.
Is the access in EPC free?

What part # you getting? post here.
According to your vin# you provided, post #12 link

EPCs ===> I use several sources, here's a few.
mbepc.net but it seems to have issues now on access (not sure why)
catcar.info
mbpartscenter.com
ilcats.ru
 

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Registered
1995 c220
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13 Posts
Discussion Starter #18
I changed the spark plugs, I got the Iridium ones when I bought the car did some digging on the forum and I have to agree the copper Bosch made for the c-class should be used.
Checked the wires everything was good, the thing has OEM wires in it and I would keep them in until they give out, I am hopefully getting the MAF delivered to be tomorrow will post after the new MAF is in.
For now a slight improvement is seen with the idle it is not as horrendous but definitely not as smooth as it is suppose to be, engine still stalls at stops, but the frequency has dropped after the new plugs.
Fingers crossed I get the MAF in time and it does turn out to be the root cause of the issue.
 

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W163 and General M Gremlin
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4,650 Posts
From the post number 12 link, the MAF sensor part number is A0000940048. The part number I see in my Bosch body is 0280217100. I stand corrected, maybe the difference in part number is because in your link, it is only the MAF sensor's part number and in my Bosch part number, it is for the whole assembly.
Is the MAF sensor which you purchased also a Bosch? If I check eBay, it seems the sensors are available but they are not Bosch.
Is the access in EPC free?
Good eye jake. :)
Upon, further investigation, the part # in post #12 is just the sensor.
I was fooled by just looking at the photo of the maf with part#15 as it's label for the 'photo of the maf'. My bad.
I assumed it was for the part # for the whole thing.

I always purchase genuine Bosch when it comes to these components. Never generic.
Some members have had issues with non-oem.

EPC free
 

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W163 and General M Gremlin
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4,650 Posts
Spend some time waffling thru it and getting familiar on how to navigate and understand the jargon they use for areas of your vehicle. It's a good resource for any DIY or even parts purchasing.
 
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