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-   -   Car revs to 4K and holds RPM -FBM (https://www.ft86club.com/forums/showthread.php?t=135418)

Kerber23 06-24-2019 11:19 AM

Car revs to 4K and holds RPM -FBM
 
Hello here are the current symptoms I have.

Log: https://datazap.me/u/kerber23/engine...g=0&data=23-30

3 Codes (P0108, P2127, P2122)
Car idles very roughly/stalls sometimes on startup.
After Startup the CEL and Traction lights illuminate. The RPMS begin to climb to 4K and hang there.
Unresponsive to the accelerator.

What have I done?
Reflashed tune
Replaced throttle body (have 2 working ones)
Checked MAF/MAP/Throttle body wire connections, they seem fine

What was happening before this?
Took my car to a shop for a suspected boost leak that I couldn't find, ended up just being a broken gauge. The shop had tightened some of my oil return lines and on my way home one of them came loose and pissed oil everywhere. I replaced the serpentine belt and she was good to go after I tightened the hose.

About 40 miles after replacing the belt I notice that im not hearing the open dump on full load, and I feel a substantial dip in power. While trying to figure out what was going on I floored it and then the CEL/Traction light came on and ever since it does that idling thing.


Thank you for taking the time to read this. Any tips would be appreciated. I checked for other posts and they didn't seem to be very helpful.

My Car: 2013 FRS - Full Blow Motors Turbo Kit - T57 Turbo, 550cc injectors, AEM 370LPH fuel Pump.

MCTeeJ 06-24-2019 02:20 PM

Do you have a stock MAP sensor? Have you contacted your tuner yet?

Kerber23 06-24-2019 02:30 PM

Quote:

Originally Posted by MCTeeJ (Post 3230525)
Do you have a stock MAP sensor? Have you contacted your tuner yet?

No, I have FBM's 4BAR sensor. My car has been boosted for quite some time and never had this happen!

wparsons 06-24-2019 02:49 PM

First step is looking at what the error codes mean... a quick google search tells you what the generic OBD code means.

P0108 OBD-II Trouble Code: Manifold Air Pressure (MAP) Barometric Pressure Sensor Circuit High Voltage Input Problem.
P2127 code is a generic OBD-II diagnostic trouble code indicating a fault with the throttle or pedal position sensor. This code may be seen with other throttle and pedal position sensor codes.
P2122 OBD-II trouble, or fault, code means that the vehicle's on-board computer has detected low voltage in the throttle position sensor (TPS), which is usually below 0.17 volts.

I'd start by actually measuring what's happening with the throttle pedal sensor as well as the TPS (in the TB). If you have two TB's with the same issue I'd suspect wiring or a connection issue, chances of two being bad are basically impossible. The fact that the first code also sounds like a wiring issue would have me checking the whole harness for signs of damage, and also checking all connections. If oil got into a connector it could be causing all kinds of weird issues.

EAGLE5 06-24-2019 02:57 PM

loose vacuum lines?
dirty wastegate?
dirty map sensor?
broken throttle sensor?
have you logged the ecu while it does this and checked the results?

Kerber23 06-24-2019 03:24 PM

I'll go get it and check the harness. Map sensor seems clean. The cables going to the throttle body look fine. I'll also so some logging and upload them. As for the codes I did look them up which is why I was using another throttle body. But thank you for breaking them down. It seems like an electric problem.

EAGLE5 06-24-2019 10:58 PM

Throttle body and throttle position sensory are totally different things.

Kerber23 06-25-2019 12:12 AM

Quote:

Originally Posted by jsimon7777 (Post 3230708)
Throttle body and throttle position sensory are totally different things.

My understanding that the throttle position sensor is located with the gas pedal correct? I don't have a voltmeter but I did unplug it and the idles still hung at 2K RPM. I just assumed the sensor you where talking about was apart of the throttle body in the black housing. I didn't think it would be so far away from the TB. Im sorry.

Tonrogs 06-25-2019 12:25 AM

I would start by checking the ground cables. Make sure everything is connected as it should be. One below on each side of the heads. Another at the starter. Then the battery to the chassis. Check all with a meter.

EAGLE5 06-25-2019 04:46 AM

Quote:

Originally Posted by Kerber23 (Post 3230739)
My understanding that the throttle position sensor is located with the gas pedal correct? I don't have a voltmeter but I did unplug it and the idles still hung at 2K RPM. I just assumed the sensor you where talking about was apart of the throttle body in the black housing. I didn't think it would be so far away from the TB. Im sorry.

So it went from hanging at 4k to hanging at 2k without the throttle position sensor connected? Funky...

wparsons 06-25-2019 11:47 AM

Quote:

Originally Posted by jsimon7777 (Post 3230708)
Throttle body and throttle position sensory are totally different things.

Quote:

Originally Posted by Kerber23 (Post 3230739)
My understanding that the throttle position sensor is located with the gas pedal correct? I don't have a voltmeter but I did unplug it and the idles still hung at 2K RPM. I just assumed the sensor you where talking about was apart of the throttle body in the black housing. I didn't think it would be so far away from the TB. Im sorry.


TPS (throttle position sensor) is in the throttle body, even on drive by cable cars. The pedal sensor tells the ECU how much throttle you want, the TPS tells the ECU how open the TB actually is.

Kerber23 06-25-2019 11:47 AM

Updated post to have log

wparsons 06-25-2019 11:51 AM

Quote:

Originally Posted by Kerber23 (Post 3230562)
I'll go get it and check the harness. Map sensor seems clean. The cables going to the throttle body look fine. I'll also so some logging and upload them. As for the codes I did look them up which is why I was using another throttle body. But thank you for breaking them down. It seems like an electric problem.


Get out a voltmeter and actually measure the voltage at the TPS (on the throttle body). If the code is saying it's below the minimum voltage, and gives you the expected minimum voltage, that's a very good place to start.


If you're going to go with the logging route, log both the throttle position and pedal position and give the throttle some obvious inputs, look for it to be logged and see what the TPS is showing at the same time.

wparsons 06-25-2019 11:57 AM

Zoomed into here, you can see the TPS is showing an angle much bigger than the pedal is requesting, and that's also where the RPM's are hanging.


https://datazap.me/u/kerber23/engine...zoom=4181-6544




What is logged by "atmospheric pressure bar"? Is that the MAP sensor, or ambient pressure? If that's the MAP sensor then it might be the issue, it gives the exact same value across the whole log.


https://datazap.me/u/kerber23/engine...zoom=4181-6544


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