Power Loss and Throttle Issues

500
fiat

#1

I have a '15 Fiat 500 Abarth automatic transmission that I drive with manual shifters 100% of the time with ESC off. After taking it the car to the dealership to replace the throttle body (they also updated the PCM) my car simply doesn’t run the same. It feels like a huge lost of power. At highway speed, I can no longer drop it to 5th and pass anyone up. When I do that at WOT the car or RPM no longer surges and it seems like there’s a rev limiter at about 3500 rpm. The car has been at the dealership for 2 weeks now and they insist the car drives fine even tho they acknowledge that the data proves otherwise. Anyways, long story short I took so log with the Torque App and saw somethings that I thought was unusual. So my questions are:

  1. Cruising at highway speed at about 75ish mph, 2500 rpm, my throttle position is at WOT and the throttle body opening is at 25.5%. Is this correct?

  2. The throttle body data shows that it can only open 25.5% maximum. Is that correct? Shouldn’t it be 100% (or close to) if I’m at WOT?

  3. My pedal position is at around 30% and the throttle position is at WOT. Is this correct also?

Thanks in advance for helping me. I just want to know if there is something unusual there and make sense of this. I know for sure my car definitely does not drive the same before taking it into the dealership. Maybe someone out there can educate me on how these devices work in relation to each other. I have researched hard on the internet and it only explains what the cars does at WOT and not in relation to the other devices (e.g. cruising at highway speed the throttle opening should be etc.)


#2
  1. No, that is not correct. If the throttle is at 100%, the throttle body should also be 100%
  2. No, that isn’t correct either, same reason
  3. Huh?? That’s not right either. If it SHOWS 100% throttle body opening, is the car pulling like full throttle?

Now I’m a big fan of Torque and use it quite a bit. Are you sure you are reading the right parameters for your car? The dealer’s thoughts seem contradictory - It can’t drive “fine” if they are feeling the same lack of power you are. It would seem as thought they need to possibly calibrate the throttle body to the ecu.


#3

The dealership insist they done the throttle body calibration twice. In the Torque app, I’m selecting the highlighted green parameters only also I’m not selecting the measured value so I believe those are correct. I’m also using the Plugin App for Fiats. Here’s my 2 cents. These master tech at the dealership only knows how to remove and install stuff. When it comes to diagnosis, they suck! 2nd, he doesn’t even know how these car drives so what feels normal to him is subjective to whatever he is accustomed to. I know how my car pulls at what gears and at what conditions. I have escalated it up to corporate and the dealership said they will give them my log files. Crossing my fingers they look at it and come to the same conclusion as you did. Thanks! I’m gonna try to link my log files so people can see my data I gathered. The car is not even pulling WOT even tho it’s reporting that it is. That was what I also found odd!


#4

To add to question #1, if I’m cruising, should my throttle position be open at 100%? Shouldn’t it be like (just throwing a number out there) 20-30%?


#5

Yes. In the highest gear you might be at 25-40% throttle opening but not WOT at the throttle body nor the pedal output.

Sorry to point out that these cars are at the bottom of many quality and reliability lists. Things like this might be why.


#6

LOl no worries. I knew that going when I purchased this car. It was a hit or miss but more misses lol I bought only because I was living in NYC and parking is a pita there. I guess it’s time to trade the little guy in if the dealership refuse to fix it.


#7

I’m curious, why did you need the TB replaced?
I’d find another dealership (with perhaps more competent mechanics) or escalate to zone rep for factory service help before I took a loss by trading it in. That just rewards apathy and/or incompetence…


#8

The car threw a P0122 Service ETC Throttle Body code and went into Limp Mode. Supposedly, this car has a known issue with throttle bodies malfunctioning. In the process they updated the PCM software and in that update it updated the compression parameters for start up issues and reverse light not turning on quick enough. That was what I was told by the “master” tech. Currently, I requested for it escalate up to corporate. If that fails, then I’ll take it to an independent Fiat specialist for diagnosis and repair and take the dealership to small claims to recuperate the cost. I simply don’t understand. It’s either they’re incompetent or ignorant. Its so obvious there is an issue and they even admit to it. SMH!