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Discussion Starter #1
Highway race, went up to 133 and when I was parking my car about 5 mins after the race car felt like it wasn’t going anywhere. Put in reverse and even half throttle wasnt really moving the car.
No CEL or warnings on the dash. No fluids leaking..etc. what could’ve caused this ?
Let the car sit for about 30 mins and it felt fine. But now I’m concerned.
Current mods JB1, AMS Downpipes, AMS Intakes.
 

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Limp mode. If you have a code reader you may see an overboost code. The ECU will go into limp mode. Restarting the car after a bit will not clear the code but deactivate limp mode.
It's happened to me before I tuned my car, and a few times after. 2× for "park neutral switch input circuit" A restart cleared limp mode but the code was still there. My EcuTec cleared them.
 

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Discussion Starter #3
Thank you for the response. First time I hear about this “limp mode”. At first I thought the JB1 didn’t have that overboost effect. Makes me wonder if ecutek is safer
 

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Just my cut n paste below as a FYI.
Don't know which Q50 you have or if LDP's or full downpipes.

I'm also not a JB1/4 expert @Avedis53 <- he is.
You also may have had the ECU pull a lot of timing if it was real hot out.

Snip:
Please go to "User CP" and update your location. Also, you can add your signature with your car info. This way the forum members can make better suggestions to any questions you may have. Just a suggestion.

Welcome to the forum!
 

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2018 Q50 AWD Red Sport
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Thank you for the response. First time I hear about this “limp mode”. At first I thought the JB1 didn’t have that overboost effect. Makes me wonder if ecutek is safer
When the engine goes into fail safe mode (limp mode) due to a DTC, a lot of things can happen depending on what DTC is thrown.

There are three fail safe modes: Traveling Mode, Device Fix Mode and Combustion Control Mode.

In Traveling Mode, the ECM controls the accelerator pedal depression speed to make it slower than actual speed. This causes a drop in accelerating performance and encourages the driver to repair malfunction. The ECM also reduces the engine output, according to the rise in engine speed.

This is probably what you experienced and wouldn't necessarily throw a CEL and when you cycled the ignition, the car started up and ran normally. This isn't a malfunction but rather a protection system to prevent engine damage.

There's also Device Fix Mode that fixes the electric intake valve timing control motor and exhaust valve timing control solenoid valve in their reference positions. It depowers the engine by returning the camshaft to the position of most retard angle to prevent damage. The Combustion Control Mode does a whole bunch of things depending on what DTC is thrown and I won't go into all that here. Suffice to say that it depowers the engine to protect it also.

WOT to 133 mph puts a lot of stress on the engine and I'm not surprised your car went into limp mode temporarily. Perhaps a custom tune can reduce the possibility of going into limp mode but it won't eliminate it as the ECM programming is still monitoring the engine and will drop it into limp mode if something is not kosher.
 

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Seeeee I told you! Surprises me he did not discuss the JB1/JB4 contribution, if any.
 

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It's highly unlikely the map connections would have suddenly come loose or disconnected during a pull. Unless the owner set the boost too high, it's like there was something else going on.
 

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Discussion Starter #8
Thank you all for the information. As for the JB1 is there a safety boost feature I can enable?
 

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Thank you all for the information. As for the JB1 is there a safety boost feature I can enable?
Which engine do you have? What octane number fuel are you using? What boost are you running on the JB1?
 

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Discussion Starter #10
3.0t silversport , 91 octane & I don’t think the JB1 allows me to to change the map . Don’t have the Bluetooth feature
 

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Another JB1 to JB4 with bluetooth candidate!! A trend here. 😁
 

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Discussion Starter #12
I tried to purchase the jb4 upgrade but I unfortunately live in California and they won’t ship
 

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I tried to purchase the jb4 upgrade but I unfortunately live in California and they won’t ship
They pop up here used often. Or have an out of state friend buy and ship to you. It's easy!😉
 

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3.0t silversport , 91 octane & I don’t think the JB1 allows me to to change the map . Don’t have the Bluetooth feature
You don't need a BT dongle to make changes to the JB1 but you do need a data cable. If you haven't changed the map setting, then by default, your JB1 is set to Map 1 which adds 3 PSI of boost to the mapping across the rpm range.

There is no boost safety feature in the JB1 but the VR30 does have it's own engine safety systems as you found out.

Without knowing what the DTC was that caused your car to go into limp mode, it's hard to say what caused it. Given that you are only adding 3 PSI to the ECU boost control of a SS, it's seems unlikely that excessive boost was the cause. Whatever it was, it was temporary as the limp mode cleared with an ignition cycle.
 

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Do you think it’s something I should worry about or brush off for now ?
If it only happened once, your ECM was doing it's job when you were pushing the vehicle rather hard and I wouldn't be too concerned about it. If it consistently goes into limp mode, then you should take the car in for diagnostics.

The problem is unless the car throws a permanent DTC, any DTC thrown when your car goes into limp mode will clear with an ignition cycle. If this happens again, you may want to consider driving the car directly to your service department (if feasible) and without shutting off the engine, have them connect their CONSULT scan tool to your car to read any DTCs.
 

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Do you think it’s something I should worry about or brush off for now ?
If it happens again easily, it's nice to know what the code is. I periodically check mine as some may not pop a CEL, or put you in limp mode.
 

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Discussion Starter #18
Will do so. Now assuming I take it to get serviced I would have to disconnect the JB1 right
 

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Will do so. Now assuming I take it to get serviced I would have to disconnect the JB1 right
Only if you want to hide (deceive) the dealership about your running a "tuner". You easily can. Not that I condone that behavior with a warentee claim, if asked, and lie about it. In this case I'd remove it. No point volunteering the info as it may be totally unrelated.
 

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No point volunteering the info as it may be totally unrelated.
Yup, like when I took my Q into the dealership last week for a window rub (seal replacement), I removed the Ecutek BT dongle from the OBD-II port, and my BMS Pedal Tuner is positioned in the dash out of sight. No need to advertise.
 
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