Hello ScionLife,

It appears my Mass Fuel Sensor is broken, and the dealership is blaming it on an aftermarket exhaust.

Before I go into it, let me explain what the car does. I have a 2011 Scion tC, 6-speed manual with the following mods: Descendent Cold Air Intake, Megan Racing Header, custom exhaust (muffler shop), and an NST crank pulley.

The car feels like it boggles down (hesistates) when I accelerate, and it won't go right away when I floor it. After it creeps past about 3k rpm, it will then shoot to the red line normally. It boggles even when in idle, neutral, etc.

I took it into the shop, and the dealership said I needed to check with the auto sports place that worked on my car. I checked with them, and they ran diagnostics on the car and showed that the car is running too rich, saying that there is a problem with the Mass Flow Sensor.

Now, I only have 16,000 miles on the car... and the salesman put me on some extended warranty for $12 more a month that would insure they would take care of issues with the motor EVEN if I put on aftermarket parts. The guy seemed trustworthy, and I'm hoping this was not a lie.

Anyone know if I should be covered under warranty, or am I SOL? Any advice helps, please and thank you.

 

If its the maf sensor in the intake (mass air flow) I'm not sure. I don't think an exhaust would have much influence on the intake. But I dunno if they can claim the descendant intake caused it. Not sure how that all works

Any CEL? Codes?

 

At first, no. I had a slight issue with the CEL coming on when I first installed the header, but that was because I put the CEL eliminator on the o2 sensor for the header instead of the downpipe.. but then that fixed the issue. I had no lights come on until yesterday.

The lights that came on were the CEL and the slip indicator. Right before I got to my work, the car acted like I stalled the vehicle. The radio remained on.. while I was at a stop.. then all the lights came on.. including the battery light.. and I had to restart the engine.. But no issues with starting. Just keeps bogging down.. Really strange.

And of course, the dealership will not retain any sort of responsibility.. just saying I am SOL and need to replace it myself. I am getting it replaced tomorrow for $550 out the door.. including diagnostics.. etc. Plus the shop is giving me documentation stating they will warranty the part for 2 years.. so I guess that's my silver lining for the night.

 

i have the same issue and its due to the intake most are having this issue the only way to fix this is to either remove the intake or have it tuned it really sucks when your trying to show off and that ____ happens... i notice it happens if the car goes from runing in warm weather to cold weather like if i start it and drive around during the day at 65 70 degrees then get in it at night and temp has droped to 30-40 degrees not sure what it has to do with it but

 

So is this just a problem with the tC2 or do other cars have this issue? I haven't seen any issue in the year I've had it until now. You might have something on the temperature.. Because we were in 90 degree weather, and right now it's around 60 and 45-50 at night. But I didn't have this issue last year, so not sure.

The guy who is replacing it says once he gets a new one in there it should be fine.. But after reading what you said, it makes me wonder till WHEN should I be fine, ya know? I might end up ditching the Descendent and go with TRD, so at least that would be covered, but haven't made up my mind yet.

 

Thought about resetting the ECU?

 

and im wondering if its your mass fuel sensor or your maf sensor

 

No, haven't tried that yet. I have thought about having it retuned to get a proper air/fuel mix.. but haven't done it yet.

 

That's what my friend was suggesting, but the guy at the shop says he narrowed it down to the Mass sensor, so I just said, "Uh, yeah ok." lol I've never had this issue in the past with any other vehicle, so don't know much about the situation.

 

Try the ECU thing wouldn't surprise me if that fixes it let it relearn it's values

 

reset the ecu,then let it idle for a bit,to relearn its values and see what happens

 

This will sound stupid, and I could just not be lazy and look it up.. But how do you reset the ECU? lol

 

Just unplug ylur battery for about 15

 

Hahaha really, that's all it takes. Wow, I'm an idiot. Haha!

 

and once you try to start your car for the first time it will stall its supposed to dont freak out haha

 

Hahaha! Ok, no worries. Kind of like waking up a bear in the middle of hibernation. Err... Maybe that would be worse. lol

 

im gonna go with yes much worse

 

Let us know what happens after the ECU reset

 

No problem.