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Sputtering under acceleration with engine light?

Tiny
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So, I got my live scan tool today. It came later in the day, so I didn't have much time to mess with it. I did get a confirmation of the cylinder one misfire and went into the live data a bit. Now you're talking about the freeze frame. Does that happen when you have it in live scan mode, and does it just freeze frame all the info when the fault happens?
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Sunday, March 12th, 2023 AT 4:30 PM
Tiny
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Hi,

It will automatically save the freeze frame data when the issue occurs. The scan tool doesn't even need to be connected. If the scan tool you have does retrieve freeze frame info, you should be able to check it now.

Let me know.

Joe
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Sunday, March 12th, 2023 AT 6:49 PM
Tiny
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So, this is actually the second freeze frame because I erased the codes and had to go and get the engine light to come on again. Sorry for doing it this way for some reason I can't print the freeze frame data from the PC.
They are in no particular order.
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Monday, March 13th, 2023 AT 10:50 AM
Tiny
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Monday, March 13th, 2023 AT 10:57 AM
Tiny
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Monday, March 13th, 2023 AT 10:59 AM
Tiny
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Monday, March 13th, 2023 AT 11:00 AM
Tiny
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Monday, March 13th, 2023 AT 11:01 AM
Tiny
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Hi,

I need to know something. Two things stick out to me, the IAT and STFT. (Intake air temperature and short-term fuel trim).

The STFT is high. In a perfect world, it would stay at 0%, but yours is at 23.4% which indicates the computer is trying to add fuel. Under normal conditions, the trims should stay between -10% and +10%. This can be the result of a weak fuel pump or an engine vacuum leak. However, the IAT makes me question it. The IAT temperature indicates 69F. I'm not sure where you are located, but that should be approximate under-hood temperatures. If you are in a very cold climate, I guess it could be okay.

I need you to check one more thing. See what the engine coolant temperature sensor indicates. It should be around 5 degrees difference. If it isn't, I suspect the IAT is failing.

Let me know.

Joe
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Monday, March 13th, 2023 AT 8:44 PM
Tiny
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I believe what you're looking for is the ECT, same thing right? It shows 174 on the freeze frame data. And if it matters, I took it for a ride and watched the STFT and it varied about 7 points max either side of 0, and mostly around 2 points. It also showed similar IAT temperature.
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Tuesday, March 14th, 2023 AT 8:41 AM
Tiny
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Oh, and I live in Delaware which is a pretty moderate climate.
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Tuesday, March 14th, 2023 AT 9:47 AM
Tiny
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Hi,

The fuel trims sound good then. When you say the IAC showed similar readings, are you referring to what I read on the pic or did you get a reading similar to the ECT? And yes, the ECT is the engine coolant temperature sensor.

If the IAT was similar to the ECT, I wonder why it was off on the scan tool originally. The engine was at operating temperature when checked, correct?

Let me know.

Joe
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Tuesday, March 14th, 2023 AT 7:14 PM
Tiny
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No sorry, meant to say it was similar to the pic, in the 70s. And yes, it was at operating temperature.
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Tuesday, March 14th, 2023 AT 7:27 PM
Tiny
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The IAT is likely faulty. It should be showing a similar temperature as the ECT or under-hood temperature.

The IAT is integral to the manifold absolute pressure sensor (MAP). I attached a pic below showing its location.

Check the wiring to it, make sure the connector is in good condition, and I would recommend removing it for inspection. There shouldn't be that big of variance in the signals. Five- or ten-degrees difference I could suspect. This is way beyond that point.

Let me know what you find.

Joe
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Tuesday, March 14th, 2023 AT 7:47 PM
Tiny
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So found it think. This appears to be part of the MAP sensor or boost pressure sensor on turbo engines, right? That is what I'm seeing online anyway. I disconnected the harness and looked in perfect condition.

https://shop.advanceautoparts.com/p/fae-boost-pressure-senso-b4080454206fae/11894186-p?c3ch=PLA&c3nid=11894186-P&adtype=pla&product_channel=online&store_code=&gclid=Cj0KCQjw2cWgBhDYARIsALggUhoIpPiTCLZITXB8RBbMkhesIEkxKB0JgBbneQb2eJlUlz-IsB5opcEaAu_XEALw_wcB&gclsrc=aw.ds
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Wednesday, March 15th, 2023 AT 11:24 AM
Tiny
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Hi,

Yes, that appears to be correct. The IAT is integral to the MAP. Also, it can be referred to as a boost pressure sensor on a turbocharged engine.

Let me know what I can do to help.

Joe
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Wednesday, March 15th, 2023 AT 6:49 PM
Tiny
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So, I ordered a new sensor. Should be here Monday. I took the suspect sensor out to look at and noticed a film of oil on it. I couldn't see anything inside and stuck a long road inside and nothing also. I cleaned it up and took a ride and checked it again and nothing. Is this something to be concerned about? I really haven't driven it much since I've been retired. Mostly just local.
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Thursday, March 16th, 2023 AT 10:43 AM
Tiny
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Hi,

When you disconnect the sensor, the computer sees it as an open circuit. To allow the engine to continue running, the computer substitutes another "fixed value" which is halfway between a rich and lean fuel mixture. As a result, the engine can run properly.

You should be fine until the new part arrives. If you told me you had to take a 1000-mile trip, I would be concerned. LOL

Let me know what you find or if you have questions.

Take care,

Joe
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Thursday, March 16th, 2023 AT 7:43 PM
Tiny
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So got my part today, earlier than expected. That's the good news. The bad news is it's reading basically the same. Does this thing need to be calibrated or something? I see mixed answers online. I disconnected the negative battery terminal. Is there something else going on causing this maybe?
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Saturday, March 18th, 2023 AT 2:29 PM
Tiny
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Hi,

No, there isn't a relearn for this sensor. Do me a favor. Clear any codes and drive it to see if the same codes return.

Let me know.

Joe
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Saturday, March 18th, 2023 AT 3:48 PM
Tiny
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So, I did that, and I also switched 1 and 2 coils again for the hell of it. Because I didn't clear the code the first, I did that. I did get the engine light to come. It flashed a couple times. So, no code generated, but there was a pending code and guess what? It was a cylinder 2 misfire. I'm guessing a pending code is one about to happen or something like that.
So, if I need a new coil should I replace all 4 and if so, the plugs as well? Or can I get away with just one for now to see if it fixes it?
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Sunday, March 19th, 2023 AT 8:16 AM

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