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It looks like someone drilled a hole and stuck the nipple of a map sensor into that hose. Looking at other engine chambers I don't see any other c63/m156 with anything there. Im still learning about the inner mechanics of our cars and automotives in general so excuse my ignorance. I did ask the almighty google and through out this forum. I'm baffled
Naturally aspirated...I took the sensor out and it's a mass air pressure sensor attached to a two way connector connecting the two sections of the molded hose
I'm not sure how I feel about that....but as Jason said, it's meant to be on the intake manifold. If you look to the left side where there's the four harness connectors, it should be down there. Presumably you must have one there to block the hole in the manifold. No idea why you've got one in the place on the pic or what it's connected to.
I'm wondering if it WAS a blown car at some point that someone returned to N/A but left that in place...I have seen good only knows how many M156 engines and have NEVER seen that before
its there and plugged into along with the rest of the harness. I bought this car new and drove it off the lot. I never force induced it albeit I have a supercharger from weistec but no lower intake manifold for it.However, it did spend 4 months at the dealership getting nothing fixed. Rusnak of Arcadia in California is ****ing terrible. They returned my car with half of my header bolts loose and or missing all together. I took it to an indie shop and they bolted everything down when they put on my LTH.
A little background I've been dealing with a mysterious lean condition and have been hunting for a vaccum leak I can not locate. Not with carb, not with smoke or new intake gaskets. I was looking at a few posts on this forum and noticed no one had that sensor but me but it seems like it's in use. It's thermal wrapped and heading towards the intake manifold along with all the other wires. This is weird because the y hose looks like it was designed to fit this sensor. It's not ghetto rigged. The y hose also has a part number with A156...so it seems it is made for my car.
I got a p0101 here and there but it usually goes away on its own. Only the obdii apps tell me I have a lean condition along with my obvious lack of power. Dynoed at 415/407 with full bolt ons and tune. What's weird is that LTFT doesn't reflect the STFT
So if my own MAP is there with harness plugged in...and this mysterious boost sensor is there with a seemingly important plug also connected. Where and what information is it feeding my ecu and wtf did I grow a new cable on my harness. My car is so ****ing weird. I'm almost positive rusnak of Arcadia installed it I just don't know why. Hell they probably don't know. Rusnak literally told me in our hunt to find the source of your problem we created more problems. Corporate ended up paying me 4 grand for literally keeping my car there and playing Jenga with my engine.
First thing I would do it find a replacement rubber thing and lose the misc sensor. Better still...disconnect it at the connector and see what effect if any it has on the car.
If you're bored this weekend, yank off the airbox and have a look at the oval port by the maf. If the gap between the plastic and the metal insert is really big and you can see through it, that might account for enough unmetered air to cause it to run lean.
That all looks after market to me. You can see where the tube has been cut to splice in the sensor, and then that white cable tie holding it in place. All very weird!!!
That sensor is original & it is correctly placed. Both of my C63's have it & it is on most/all ROW late-release C63's.
As best as I can tell, it is for verifying/measuring the air from the auxiliary air pump to the ECR system - part of the emission compliance / EPA compliance.
It is not possible for it to cause the engine to run lean as the air enters the exhaust (not intake), however it could cause a lean code if too much air was pumped into the exhaust & the lambda sensors then measured that result.
However, it was probably one of the last ones to be sold as I bought it late 2015. So if that's not the culprit to my lean condition i an baffled. The o2 voltages loom relatively normal , my mafs had been replaced, air filters replaced. My fuel pressure seems to be normal.
I am reasonably sure the Air Pump Switchover Valve is the small valve with the small vacuum tubes in it as shown in the image, however the sensor being questioned has 19mm in-line ports.
As BLKROKT states, unlikely to contribute to lean modes.
What is the condition of the cats? Have you checked the PCV valve and the PCV hose?
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Just spitballing here, but where's the MAP sensor for our car normally located? Could it have been relocated here? Because if the ECU is taking readings from here - in a gas recirculation pipe - instead of the manifold, then that would cause all sorts of funkiness.
Edit: see Celicasaur's post above. If the ECU is taking signal from mixed-up sensors, it would be a big problem. I assume same plug type. Is it possible that the plugs are switched somehow.
08-02-2017, 02:19 AM
