IAT causing massive throttle lag?
 

Hello all, so I'm fairly sure that this has been covered at one point or another. I did search for an hour or so and really didn't find much in the way of this perticular issue. So thanks in advance.

This just started to happen once ambient temps went above 80-85f. Once the intakes get heat soaked I'm assuming this is whats happening, the throttle response is being severly cut till around 3500-4k rpms. I will be at a stop light and go to take off and oh hey your car as 45hp for like 5 seconds.

Is there any way to mitigate these issues, can they fix this in a tune? Or what can I do to prevent this? Any knowledge/advice is helpful thanks.

P.S. Is unplugging the YAW sensor the only way to cut traction control 100% :ugh2:

Throttle response can be tuned with uprev -- OEM tune is notoriously laggy.

Unless you have open pod intakes (especially un-shielded and under the hood) you shouldn't be suffering from any major heat soak.

For the yaw sensor -- I believe so, and there is a thread on wiring in a toggle switch for it...

The ECM will cut back on engine output once IAT gets above some temperature that I can't remember right now (it's pretty low, 90F or so, but I won't swear to it). The IAT sensor is in the MAF sensor that is mounted in an uninsulated plastic tube. If you don't have plenty of air flow through the engine compartment, the MAF/IAT can be significantly hotter than ambient. A CAI should help but may not cure the problem on a hot day in stop-and-go traffic.

Traction Control can be nuked via the ecu tune

As for the issue your having , that's strange. Can you post up a log?


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Ok cool this is what I figured as it just started to happen once the ambient temp went up higher then normal here.


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Ok so is it safe to say the only real way to avoid the heat soak is to move the iat sensors Closer to the front of the car that way avoiding engine/exhaust heat.


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It's the ambient temps being high for sure I drove it last night when it cooled off and it was perfectly fine. Went and railed on it, not a hiccup. Then this morning it was a little cooler than yesterday and it is fine so far today. So thanks for all your info and I'm definitely gonna need a tune anyways with the mods I have so I'll get all that traction control **** taken care of then I suppose.


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Are you Turbo ? I've never seen this problem on a Turbo car and turbo cars have much higher air temps because it's charge air not ambient.

I don't think anyone can claim anything unless they have some sort of data.


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Yeah I just assume w/e tune or emu they run on a turbo car can accommodate for up to 200 degree intake temps. like I said I did some research and the only similar thing I can really find is people's 2013 models throttle bodies and tps being bad but they're throwing codes. Or the brake switch being bad. And no I'm mostly stock just FI non res test pipes aam mid pipe and short tails. Stock tune nothing other than exhaust. So I guess I won't worry to much about it unless it starts happening when it's cool out as well. I'll just try to move iat sensors up towards front of car and get as much ventilation in the engine bay as possible.


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There's no way you are seeing IAT's that high above ambient with the factory airboxes and especially at only 85 F -- I live in FL and datalog, so trust me on this one.

It's almost definitely a weird fuel trim or just the typically laggy OEM throttle response. Even if you were logging vastly higher IAT's than ambient, I'd predict a faulty sensor before an actual physical condition.

If you lived somewhere getting closer to 100 F and sat in stop and go traffic all day, I doubt you'd see IAT's go anywhere near 200 F.

Lots of things can cause laggy response (any number of sensor failures, vac leak, etc), but I'd be really stunned if you had actual IAT's confirmed via data log and a second underhood thermistor that showed this to be the problem.

No I'm not saying they were 200 degrees I'd say more like 100-120 sitting in traffic and not getting much airflow in the engine bay. But it has definitely only been when the temp hit 90 degrees here


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Ok, those values definitely are in range at idle, but that's not hot enough to cause any lag.

Is the lag at WOT or light throttle?

If the former, it's almost definitely that the OEM tune just isn't as responsive as it could be (there's a whole thread on this with tuning code that can be cut and pasted into uprev).

If the latter, it could be any number of things including vac leaks, wonky sensor, etc. Even clogged air filters could cause that.

Tell us more about your set up. Is it all stock? Do you have any datalogging capability?

Yeah it feels like clogged air filters to me. It's like it's starving for air till about 3500 rpm then it will surge forward and is fine at high rpms. It's mainly taking off and when I get on it at lower rpms it's like I said starved for air. And no data logging or anything like that. It's got full exhaust. FI test pipes aam mid pipe and shirt tails. That's all that's done as far as power mods.


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Did this just start happening one day or had it always been present at 85+ ambient?

Yeah It just started as soon as ambient temps went above 85 that I noticed anyways.


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Car went into limp mode this morning on way to work. Did oil change today 1/2 quart low and the drain plug had some little bits of metal on it not a lot but some. Chalking this up to oil consumption problem and taking it to dealer under warranty. Fml


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cheap gas

Only use shell 93 octane


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That's what I use (ethanol free only) ...you haven't changed your tires lately;or checked your pressure?.. I keep mine around 38 or 40 year round; and when the weather broke hot, my traction light was flashing in the curves on me & reducing power.... Also if you're running K&N air filters (or something with oil) make sure they're not over oiled/ you could have your mass air flow sensors oiled up...
Just a couple things to check.

just noticed you were Turbo,,,,i know these cars are known to derate power at high engine oil temp.(not sure what that is set at) also ck. for charge air cooler pipe leak (hose or clamp) and Fuel pressure.
after the initial lag;does it perform good on the open road?

Attachment 105334 this is after sitting at work,,,levels off between 104,105 some days at highway speeds.


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