DaODB

Well, with no better words and to express my stress, I ****ed up.

After my CEL intermittently showing up, and the "banks too rich" being the codes, I decided to try to research the problem. I noticed a bucking in my car whenever I try to accelerate fast before my car is totally warmed up. Symptoms that seem to be from the MAF Sensor.

I kept researching and found I can do this by myself. Tried it, and I don't even know what the hell I did wrong. Possibly I touched the inside of the sensor with the CRC MAF Cleaner, but who knows. All I know is when I put the sensor back in, my car had the worst time trying to start it ever has, and when it finally did, the RPMs were bouncing up and down, black smog was coming from my exhaust, and the lights in the cabin were dimming in and out. Visit Workshop ESP and check engine came on right away.

I don't even know where to start. Do I try to drive it in this mess to the closest shop to get the check engine light checked out? Order a new Bosch MAF Sensor online and replace it myself? (Where is a good site? Found some for around $200)

This is such a stress before the first day of classes! I am just praying that I didn't plug in the MAF Sensor all the way or something...

thanks

pcy

Disconnect the electrical connector to the MAF and start the car; does it run better?

You may want to get a OBD code reader and find out what diagnostic codes are set.

DaODB

I just tried it this morning (still attached) and the ESP doesn't show up anymore, so I guess that's a good thing. All the symptoms of a bad MAF are occurring (Smoke, sputtering idle) I also checked the temperature gauge and it doesn't seem to be moving.

ScottyKilmer (Great channel on Youtube) said I probably didn't let it dry long enough. I believe I did, and I guess I was right considering it still was showing problems after a nights rest. I am assuming I touched the wiring with the tube coming from the CRC Can, but I do not remember 100%.

I will disconnect the electrical connection to see if it is better and take it up to Autozone to get the codes after class today. (Around 5) I am assuming I can keep it in the housing, and just unplug the electrical socket?

Thanks

Glyn M Ruck

Please check the engine temperature sensor & connections & wiring. It looks like the car thinks it is ice cold & has full mixture enrichment.

The ECU is probably not getting a temperature reading to control mixture enrichment. That is also why the Temp Gauge is not working.

Bad temp sensor or connections including earth are usually the cause of this sort of smoking due to overfueling. I'm hoping you just disturbed the wiring to the sensor.

Good luck!

DaODB

Thanks for the response.

Could you please put it in Lego-like directions for me? I am the biggest amateur out there when it comes to cars, and rely on the DIYs of this forum

Thanks again!

Glyn M Ruck

Temperature sender unit is no 29 on the front of the engine. Check that it is grounded properly & that wires are not damaged or disconnected. You might have to replace it if it has failed.

DaODB

Well I tried to look and all looks good to me, lol. But what do I know!? So here's some pictures ... hope it helps








The tube on the left has a hole in it on the bottom. I took a picture of the MAF too.

I disconnected the MAF and the same problems were occurring. I did not try to mess with anything else during the MAF cleaning, so I am confused as to why more problems are starting to develop!? It was all fine before I attempted to clean it, besides a little bucking when the automatic went into a different gear, and an intermittent check engine light. I assume that the cold start has to do with the fuel injectors and not the MAF

Thanks!

SickSpeedMonte

Is it just me or does that diagram show the temp sensor behind the arm of the tensioner?

Glyn M Ruck

Then I think your temp sensor has failed. Maybe you shorted something. You will never get this right without your ECU receiving the correct engine temperature & your temp gauge operational. They use the same sensor.

You might have more than one thing wrong but if the wiring is OK & no connections corroded. (Pull off the temp sensor plug & clean with switch cleaner) then replace the temp sensor.

If you are uncomfortable working on this car find a good indy that knows Benz to help you.

Glyn M Ruck

Yes ~ It's below the water hose.

DaODB

I was trying to get this done with the least amount of bucks spent, but I guess there's only one way to fix it properly. Do you know how much it'll run me?

Is this what I was supposed to be looking at??

SickSpeedMonte

No, look under the water hose, behind the idler/tensioner arm.

Glyn M Ruck

Here:

DaODB

I honestly don't see anything where the arrow is pointing! Just a big metal block. I am about to walk to the nearest mechanic and try to convince him into letting me borrow a OBDII sensor.

EDIT: I walked there and he wouldn't loan me one, and said that they wouldn't scan Mercedes anyway. I called the independent Mercedes place "Furrin Auto" and they said they charge a Diag for it, and the Diag will stay on top of the bill even if I do get it fixed. I don't think the actual dealer charges with Diag if you choose to get it fixed.

So now the question is... Is this safe to drive? I mean not around town but straight to the shop? For instance, if I went to AutoZone to get the codes and then straight back home? I'm scared!!

Glyn M Ruck

Maybe the sensor position got moved on final production M112 engines?

Yes it's safe to drive but you might need an oil change after that because fuel is going to get in the oil if it's overfueling enough to smoke.

Sorry. I have sold my car with a M112 so I can't go & look.

DaODB

How much do you think (rough estimate, I know you guys aren't looking at the car) this will cost me? I still have books and electricity to pay for (life of a college student) so I have to be on a budget.

I'm about to call back at the dealer and try to explain the best I can on what's happening, and will let you all know! They have fixed my valve casket covers before.

EDIT: Just spoke with him, and he said that it could be a number of things so I shouldn't drive it. He gave me a number to a towing company, and said that the diagnostic will not be added on to the bill of the service. (great news) But I'll have to put that money towards a tow truck, anyhow. He may have been throwing numbers around as example, but said if it's $500 and the diagnostic fee of $110, I won't have to pay $110. Not sure if he was estimating how much this repair will cost or not.

Also, he said that since the temperature is not showing up and there is black smoke, it could in fact be overheating, which is the reason not to drive it.

2nd EDIT: $75 towing from my home to the dealer.

Glyn M Ruck

Black smoke = overheating. BS ~ dealers. The temp sensor is $25. I have just phoned a friend to check. It has never changed position. It is below the thermostat housing below the belt where shown in the diagram.

This is what the sensor looks like.



You are going to get ripped of at the dealer. Take an extension mirror & have a proper look for the sensor.

DaODB

Night time is approaching fast and my roommate is not here to take me to the store for a mirror, but I do believe we are going tonight. $25 sounds much better than a maintenance, even a tow truck! Would this price be online or at a shop I can pick up locally?

Thanks so much!!

Glyn M Ruck

If you shop around you can get it for $10

http://www.everythingbenz.com/z/part...e-sensor-water

DaODB

Nice, do you know if this is Bosch, or if it matters?

It's killing me wondering if this was something I caused or if it malfunctioned on it's own. The only people I know that have been on the front of the engine like that are mechanics that were trying to pinpoint a whirring noise from my engine, which some say is the Power Steering Pump and others the AC Compressor. Not even worried about a stupid sound though, just want to be able to drive it again like I did before trying to mess with the MAF...

Glyn M Ruck

Sorry. The Benz diagrams are slightly misleading. I have corrected the picture location above.

Here is a DIY video on how to change.

This is on an E Class but same engine series.

Glyn M Ruck

Facet or Bosch are both good sensors. And it's next to the thermostat housing & not below it.

DaODB

Honestly, that video seems way over my head. It's looking like dealer, and Plan B might have to finance an old 98 Toyota...... lol



Here's an up close of the sensor... if it does any help

Glyn M Ruck

Right. See that U shaped clip. Lever that off (up) with a screwdriver & the sensor just pulls out & you can unplug it from the harness. If the clip does not want to move up then loosen that 10mm Torx on the thermostat housing & the clip will come off.

Do the reverse to install a new sensor & you are done. You will only have to top up coolant.

DaODB

Seems much easier than all of the stuff he did on the video! I will probably slide by the Mercedes dealer tomorrow and find the price on a sensor and some coolant.

Thanks so much and I will keep you updated!