Possible Causes of Power Loss

WickedSHO · August 17, 2015, 10:13:27 AM

Hey Guys,

So I have felt that my car has not been as strong lately as in the past. Yesterday while I was out an about, I did a few 0-60 runs, and they turned out a slow 5.3 seconds.
Just as a comparison, back in May, I recorded my faster time at 4.1 seconds.

Not sure if it is due to the heat or not. But I can't see me losing a full seconds just cause it is hotter.

Do you fellas have any idea's?

Scott

SHOdded · August 17, 2015, 10:20:19 AM

How many miles accumulated so far, Scott? Check turbo piping for cracks, and the clamps for coming loose. Another thing to try is to return to stock then reload the tune. Check plugs for gap?

Aging PTU/RDU fluid can also contribute to a slow performance, don't know about a full second though ...

WickedSHO · August 17, 2015, 10:32:52 AM

I've got about 10,400 miles.

I'm pretty sure I have some bad hubs, but don't know if they would cause the car to be slower.

Plugs are new. only about three to four months on them.

If I had a boost leak, how could I check for that?

BiGMaC · August 17, 2015, 10:37:04 AM

Most bad hubs seem to exhibit noise when turning the wheel while stationary... Not sure about the effect on performance.

I agree... You should be making low 4's in the car. Any codes set?

SHOdded · August 17, 2015, 10:40:12 AM

If you run Torque Pro on Android, or Forscan on Windows/Apple devices, you can easily note boost pressures (or lack thereof). You should be hitting a peak of 13+ psi with LME tunes if the SHO is running correctly.

But checking hoses & clamps would still be a priority. BTW, any smoke out the exhaust? Want to eliminate turbo/turbo oil feed issues.

WickedSHO · August 17, 2015, 10:43:51 AM

That is exactly what I get BigMac, noise when I turn the wheel when stationary.

No codes, well none that I have seen. Will Torque show them?

I've seen spikes of up to 16 psi according to Torque, just recently as this morning.

I did notice some smoke last week, thought something was wrong, but I also noticed it on most of the cars on the street that day. Weather was a bit crazy that day.

I have been noticing a lot of black residue on my exhaust tips. something to be concerned about?

BiGMaC · August 17, 2015, 10:49:40 AM

Soothing of the exhaust tips is a fact of life in the 3.5 GDI as they tend to runs rich frequently. Not to worry. If you want to explore ethanol blending tips have stayed cleaner with that... I notice it in the winter gas here in Phx. I also have noted a significant reduction in the soot since installing my MDesign CAI... But it still happens, just takes 4-5 days.

I'd have the dealer look at the hubs.

Your MyCal should read any codes set. Look for overboost as wel as inspecting the charge pipes for leaks.

SHOdded · August 17, 2015, 10:51:09 AM

Torque wouldn't show any more codes than the MyCal. Best to call LME to confirm if 16 psi spikes are too high. If they are, you may have a stuck wastegate.

What color was the smoke (black or blue or white ...)? Excessive soot on the tailpipes is usually from incomplete combustion, has the level gone up recently? How is your mpg? Any drop? Any fuel smell? That could point to a dirty air filter, a leaky injector, or a failing oxygen sensor.

WickedSHO · August 17, 2015, 10:58:01 AM

The smoke was white. But did not last long, the car was still warming up to temp.

Ne fuel smell...My MPG's, have always been up and down depending on how I am driving the car. If I am not in it all that much, I can get 13-14 MPG city driving. If I am in the throttle a lot, I get between 11-12 MPG city driving. A lot of stop and go and short distances.

I did just take a recent trip to Canada, total trip was 1100 miles. Car averaged 25 MPG, running at 75 miles 95% of the time. Seems decent to me. What do you guys think?

BiGMaC · August 17, 2015, 11:05:05 AM

Mileage in town seems low... I get my foot in it and accelerate more that briskly at every opportunity and in PHX I run the AC almost continuously. I am running the v8 tune... For over a year my mileage in town on surface streets is 19-20 mpg. 25-27mpg is what I see on the interstate if I keep it below 90mph. Makes me think something is amiss.

SHOdded · August 17, 2015, 11:20:43 AM

Might be as simple as changing/washing the air filter, or using MAF Cleaner to clean the MAP sensors. Worth a shot.

WickedSHO · August 17, 2015, 11:29:13 AM

just went out and used Torque to check for Fault codes, nothing.

I have the MDesign CAI on the car and I checked it before I drove to Canada, but maybe I should clean it anyways.

Sorry if I seem a bit uneducated, but how many MAP sensors are there?

I sent an email to LMS. See what they say.

BiGMaC · August 17, 2015, 11:31:40 AM

Quote from: WickedSHO on August 17, 2015, 11:29:13 AM
just went out and used Torque to check for Fault codes, nothing.

I have the MDesign CAI on the car and I checked it before I drove to Canada, but maybe I should clean it anyways.

Sorry if I seem a bit uneducated, but how many MAP sensors are there?

I sent an email to LMS. See what they say.

Sound like a plan. As far as the MAP sensor. There's one. It is on top of the manifold toward the driver's side. Here's a labelled pic:

WickedSHO · August 17, 2015, 11:37:36 AM

That MAP sensor is new, I've currently got the 3Bar sensor.

But I will still get some Cleaner and clean it up.

14SHOCAR · August 17, 2015, 11:42:05 AM

Quote from: WickedSHO on August 17, 2015, 10:32:52 AM
If I had a boost leak, how could I check for that?

Your signature doesn't have any mods listed from what I can tell. The first thing I'd check is a boost leak at the charge pipe outlined in this video: https://www.youtube.com/watch?v=vrhBu5XtafU

I'd also mention that my car does run slower in the warm weather we have been having over the last few days in Milwaukee area. I wouldn't be too concerned...