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Fuel cut issue please help.


Picoto
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i have a NA-T Auto which is on about 11psi of boost running the DET3 piggy back. When boosting the car is running strong but once you come off throttle and crusing it is like i am having fuel cut. so when i am driving normally the AFR will go to --- and then go back to about 13 when not boosting. when it goes to --- it like the engines dies and has no fuel then it will just come back on again. Same thing if i am in nutreal and rev the car it will cut fuel at top revs while standing still. Does anyone know what this could be as it is getting abit annoying when you driving down the road normal and it jerks on and off.

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The -- symbol is it doing that when its reach the rich side or the lean side?

 

If my memory serves me right there be a colour led running above the numbers that will show you before it goes to -- ( if you are running too rich or lean to be measured )

 

on closed throttle it will sometimes read -- at the lean side and on boost it can go to the -- on the rich side, just want to see if it is a fuel cut or over fueling

 

If you are not booting it it should always have a reading.

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If this is an AEM gauge then the -- reading means max lean. Usually from injectors cutting out, I normally see the reading on overrun.

 

First question. Has this piggyback ever worked properly, or is this the first time you are trying it and having this issue, or was it fine and this issue developed randomly?

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I've seen something similar before, it wasn't on a DET 3 piggyback, but maybe problem is the same.

 

There was an NA-T that had a TPS dodgily mounted to a ebay front facing intake. The TPS would rotate very slightly on it's mount which caused the TPS calibration on the ECU to fall out of sync.

 

This meant that when the driver put low throttle on the pedal, the TPS was not actually registering any movement. When the RPM went over a certain level, the ECU would think that the engine was in over run (no throttle, coasting, 0% TPS) and would cut fuel to the injectors.

 

You would drive along and the car would constantly cut out. If you planted it the TPS would register something and over run would not kick in.

 

If you can connect to DET 3 in realtime, maybe check to see what TPS value you are getting.

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Looks like a similar throttle body yes. In the end I had to make a new mount for TPS to sit on so it wouldn't have any flex/rotation, as well as recalibrating the TPS in the ECU.

 

Whilst connected to DET 3

 

attachment.php?attachmentid=229654&stc=1&d=1540372062

 

Where I've highlighted the red, you should be able to see the live reading of your TPS. I would check this first and make sure that the second you touch that throttle you are getting a smooth input here. If the TPS reading is not instant or replicating what you are doing with the throttle, then definitely need to re calibrate.

 

Where I've highlighted in yellow is where you can re calibrate the TPS.

 

Furthermore, if you can't get the TPS sorted for whatever reason then you can try disabling the over run fuel cut by playing with a combo of the following settings:

 

 

attachment.php?attachmentid=229653&stc=1&d=1540372062

Untitled-2.jpg

Untitled-1.jpg

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