Gas Pedal Delay

DIGItonium

That's right, it feels like A/C is running. Temps were in the low 70s when the videos were recorded.

Acceleration Problems. CPS, MAF Sensor? Tune Up? - Benzworld.org - Mercedes-Benz Discussion Forum
Mass Air Flow Sensor - My VW Lemon Bulletin Board
slow acceleration problem....o2 sensors? - Benzworld.org - Mercedes-Benz Discussion Forum
MAF sensor trouble & engine shudder during heavy acceleration at certain speeds [Archive] - bimmerfest - BMW Forums

So can I convince the dealer about MAF and/or O2 sensors being the possible culprits?

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ChrisSlicks

They are certainly the most likely cuprits for screwing up your air/fuel ratio and causing the ECU to massively pull timing. They should do a test drive with data logging to see what the car is doing.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

ninous26

Digi I think you are coming onto something. I didn't fully read into those threads but have they come up with a solution?

spearfish25

I'd like to see the results of a vented hood with accessory fans blowing air through the engine bay. I'd bet it would work wonders for the car.

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2013 Cadillac V-Wagon, RIP Z

DIGItonium

did they check the maf sensors though?

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IcedZ

Didn't ask, and I don't see it mentioned, so likely not. They probably don't consider that part of the exhaust system.

DIGItonium

I got another suggestion from someone in regards to troubleshooting MAF problems, and based on the issues I described he also thinks it's the MAF sensors. To isolate this problem, he suggested unplugging the MAF sensors and drive the car for a day to see if there is any consistency.

I'm not exactly sure about how our cars behave with the MAF sensors disconnected. My car is still down (no headlights) so I am not able to take the car to service to get it checked.

If you still have your car, do you think you can have them check or replace the MAF sensors under warranty?

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IcedZ

car = gone. I did try in the past. Car won't run without them. It idles TERRIBLY and dies when you hit the gas. I also ran the car with my OBD scanner plugged into my laptop, and they looked OK to me. But I'm also not really certified to tell these things =) Data looked consistent with what I'd expect though.. matched up with RPM's / speed.

DIGItonium

no problem... thanks for your efforts! I'm nervous about these problems affecting forced induction... wouldn't want ecu to trim fuel under boost.

I'm trying to research whether heat soak on MAF sensors is a type of failure.

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IcedZ

Yeah, that would be umm... BAD.

DIGItonium

Argh... Opera Mobile fail after trying to post the last message.

Please excuse my ignorance. Does anyone know if the IAT is integrated to the MAF? Perhaps IAT is getting heat soaked causing inflated readings by the ECU. Has anyone attempted to use an external IAT and relocate it elsewhere?

If MAF was an issue then I would end up with rough idle and maybe get a CEL, but there isn't any and the engine idles smooth. I do notice performance is worse off the line on a warm day after being stuck at the light for awhile, which is why I lag getting through intersections and making turns. So maybe IAT is reading higher than normal, and the ECU is responding to the inaccurate readings.

[EDIT] Eh, I feel stupid.
IAT location?
Intake air temp data (Stillen Gen 3, need stock)

With the turbo kit, my MAF sensors will be relocated anyhow. I'm going to ask Sam@GTM about it... For N/A owners... perhaps it's something to consider. I'd like to see if CAI owners can chime in.

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IcedZ

I figured it was integrated. Thanks for the info. It sounds like it's probably not that, but could be. I definitely agree that the problem is really awful when sitting at an intersection for a period.

6spd

from experience in the auto repair industry, id have to be very skeptical that the iat temp would be causing this problem. but i have to say, ive never felt a car lose so much performance as it heats up. i mean, 5 minutes after starting up, the car feels like a whole 'nother beast, but after 10 minutes or so, the performance falls on its face, comparatively speaking. ive rarely had the problems you guys have had, but i can certainly attest to the performance falling as temps rise.

side note, i wonder if wiring the fans to run all the time would help lower the underhood temps. sure it isnt going to run at optimum fuel economy, but it may help a ton.

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-Jay- jonathanjamesphotographer.com

KingZee

I apologize if this has already been mentioned, I haven't had a chance to read this whole thread and only started following it about a week ago but has anyone reported these issues with an oil cooler? I read that this isn't really related to oil temps but I'm wondering if an oil cooler keeps the overall engine temps low as well and helps avoid this issue?

m4a1mustang

Considering the problem occurs at any oil temp, an oil cooler shouldn't really make a difference at all.

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- Steve

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