JUAN CASAUS

Where is the map sensor located on our cars?

OverDrive

On the Intercooler below the S/C toward the rear....

JUAN CASAUS

Do I need to remove the throttle body and sc to replace it?

Lenin

It's very little room to work with but it was done before. Small hands would help. I recall RazorMB and Robert from Lebanon doing it. What is your problem that you think you need to change the MAP sensor?

JUAN CASAUS

My car has obd code P0105 which is the map sensor and is idling funny lately but yesterday the code went away. Do you think cleaning it would work?

gt4awd

Could also be a vacuum leak.

Lenin

Yes, could be a vacuum leak or an electrical problem with the TB cable.

JUAN CASAUS

I checked it today and can't find any vacuum leaks and its running fine so idk.

JUAN CASAUS

My car is having trouble starting sometimes...would map sensor cause this?

alkrstev

I am having a similar problem as you. I got the code PO105 for the MAP sensor. In the mornings when I first start the car, it turns over for a long time and stumbles before it starts. For the CEL to go away, I reconnected a disconnected rubber hose that comes from behind the splitter on the driver's side air box. I am also running out of options (replaced plugs, new gas pedal, new tcu, new transmission, new torque converter)as the car is also very sluggish and unresponsive and it feels like the throttle is lagging a lot when you first take off. I guess the only thing left to do is change the MAP sensor and the ignition wires. Let us know if you solve anything.

JUAN CASAUS

The only thing mine is doing is stumbling to start and sometimes at idle it sputters but it drives normally once it gets going. I can't find any loose vacuum hoses and I've disconnected the throttle body connector and the battery overnight like another post on here said to do but that only helped for a couple of starts. The word thing if that my check engine light only went on once for about ten minutes a couple of days ago and hasn't come on since. Any help from anyone on this would be greatly appreciated.

loudandheard

You could have an issue with your cats, they could be clogged and that's what could be giving you the sluggish response. Have you removed the throttle body splitter recently? I remember when I first got my car the car use to scream, the exhaust sounded louder, and the throttle was very responsive. After about a year the car seemed to not be as loud and almost sounded muffled and the throttle was not so responsive. I figured that it was all in my head, but you have me wondering if some thing could be wrong with my car. I replaced my intercooler pump and my car was a bit more responsive, but the exhaust not longer sounds the same.


My car is a bit sluggish to start in the morning, but I'm thinking that it could be the starter. I've noticed it being more difficult to start when it's cold, but I do not have a CEL for it. I wonder if the battery has some thing to do with it.

How many miles does your car have?

alkrstev

You think the cats have something to do with it? What do I do from there? My car is also sluggish on start in cold mornings and I have no CEL either. I should have the battery tested to check it out. Another problem that I am having is that my gas needle goes all the way to the bottom no matter how much gas I have in the tank. To make it work again properly I have to disconnect the battery and reconnect it and it goes back to normal. I replaced the fuel filter cause I thought it was clogged and making the car sluggish, but it did not help. I removed the rubber/plastic part on the throttle body that connects to the air filters, but I have not gone farther. On the other hand, my seat heaters on the driver's seat are completely dead and when pushing the button, the light wont even turn on(maybe the seat is draining the battery). BTW my car has 80k miles on it.

loudandheard

Have you replaced the intercooler pump?

Check out this thread, the fuel filter may be the culprit. Apparently the fuel filter has an integrated fuel pressure regulator built in and they have been known to be defective, even oem fuel filters.

https://mbworld.org/forums/c-class-w...d-start-4.html

A thread on how to replace the fuel filter and people getting fuel filters with bad fuel pressure regulators.

https://mbworld.org/forums/c-class-w...acement-4.html

JUAN CASAUS

Now this is making me think...my car was running great and I just changed my fuel filter from one I guy from autozone but would this give me a map sensor CEL?

alkrstev

Yes, I did replace the ic pump with a cm30 johnson, but I have not split the cooling system and dont have a larger heat exchanger. The fuel filter was new from mercedes. My car starts somewhat ok when it is warmer, but when cold, not so much. I am very worried about the throttle delay though. It feels like after I push the gas pedal to for example a thrid of the way down, it seems like it takes the car a while to catch up to speed and the gear changes are very slow and sluggish. I have to push the pedal in sharply so the car can accelerate normally.

loudandheard

I would try replacing the fuel filter and if that does not solve the issue, then the map sensor. The fuel filter is an easy and cheap fix and then I would do the more expensive fix.

So I posted the wrong second link, but there have been problems with oem filters being bad straight from mercedes. I would change that one out and see if that resolves your problem. The issue lies in the fuel pressure regulator that is built in sometimes turns out faulty.

Here's a quote from a thread I was reading about faulty fuel filters directly from mercedes:


The funny thing is that both of you have changed out your fuel filters and it seems a bit odd that you both are having similar issues. I did read up on what faulty map sensor cause and the symptoms mimic a bad fuel pressure regulator, I'm wondering if this might cause the map to throw a code if there is not enough fuel.

Parts.com has great prices on oem fuel filters if you want to try them out, if you follow this link they also have a few other vendors.

https://mbworld.org/forums/c-class-w...acement-4.html

Check to see if your exhaust has an odd smell to it, maybe something similar to gas. Try to see if you can hear a loud humming sound coming from the area of the fuel filter. This could point to a problem with the fuel pressure regulator in the fuel filter.

JUAN CASAUS

I've already replaced it but I'm going to pressure test my fuel system tomorrow and go from there.

alkrstev

Well loudandheard, now that you mentioned it, I do hear a loud hissing/humming noise coming from where the filter is. Problem is that I bought it from parts.com and its already on my car so dont know if they will take it back. I just dont understand how the filter can be bad from the factory. I wonder if somebody else had that problem with a brand NEW fuel filter.

JUAN CASAUS

I'm also getting a coolant smell now...could a leaking intercooler cause the map sensor code?

loudandheard

There have been other bad filters straight from the dealer and parts.com. If you look at the second thread, there were new filters that had faulty fuel pressure regulators. I checked out parts.com return policy and anything fuel related or used parts cannot be returned. I would send them an email telling them about the problem. I would tell them that you intend to buy another filter because you believe that the filter that you received is faulty and explain to them the symptoms you have been having. Tell them that you understand the return policy, but you want to make sure that you do not receive another faulty part.

I think parts.com would help you out if they are aware of the problem, but I would not expect or ask them for a filter. Hopefully this solves your problem, I'm not too sure that this would cause a map problem, but it may solve the rough start. Good luck.

loudandheard

Are you getting a coolant smell inside of the engine bay or is from your exhaust? Have you noticed a reduction of your coolant?

Pinpointing the problem with our intercooler is difficult, I even tried searching the e55 forum, but I didn't find anything.

JUAN CASAUS

Very little coolant loss if any but smells like the engine bay. My car is starting to idle worse now. Does anyone know what psi our fuel system needs to be st stock?

loudandheard

Maybe you need to buy the map sensor. I posted in your wtb map thread

Check out this thread for psi for our fuel system: https://mbworld.org/forums/c32-amg-c...low-rates.html

JUAN CASAUS

Thank you for the info...I've seen those threads but none of then have any real final answers. I tested my fuel pressure and the range for our cars is from 54 to 61 psi. Mine was steady at around 57 so it looks like I'm fine but it doesn't look like the system is priming itself before starting but is perfect when starting or running. Can anyone chime in on what could be the cause of this? I can't seem to find any fuel or vacuum leaks anywhere but the starting problem still persists. Idk what to do from here. I'm thinking about changing the map sensor but I really don't think that's what it is after talking to a mechanic and reading the forums. thanks for any help anyone can give