Audi TT G4+ plugin ecu ESP cutting throttle.

[lito]

I have a 2003 Audi TT225 with G4+ plugin ecu. I am having an issue with the ESP kicking in and closing the throttle body well before any wheel spin has occured. It is very intrusive and in 1st gear I cannot accelerate very much at all, especially pulling out of side roads, it still kicks in 2nd and 3rd but not as bad. Once the car is in 4th gear I can accelerate full throttle without a problem. Pressing the ESP off button makes it a little better but its still a massive problem. 

Just to be clear, I dont have any traction control activated on the ecu, this is the audi factory ESP changing the signal going from the accelerator pedal to the ecu, making it think im lifting off when the pedal is actually flat to the floor.

esp cutting throttle.llg

[Simon]

Hi Lito

With the plugin fitted there should be no way the factory ESP sould have an effect on the throttle position as the ECU has total control. I would actually expect the ESP to no longer function with the plugin fitted.

Can you also post the PCL file from the ECU so we have a matching MAP to the log.

[lito]

I didn't think it would be able affect it either, I'm guessing the ESP system must be wired into the accelerator pedal harness . I've attatched my tune, im assuming thats what the PCL file you need. I've since located one of the lateral sensors for the ESP system and unplugged it, I'm hoping this wont disable the abs and haldex system. I will report back as soon as I can test drive it

Carlos main file (modelled fuel)update.pclr

[Simon]

Throttle wise its doing what is requested so not sure if it is trimming the foot position.

Can you take a log with a couple of longer pulls in higher gears so we can check the throttle at a known 100%

[lito]

OKay so it seems I have misdiagnosed the problem. Did some testing today and it looks like its going super lean on heavey throttle inputs, then will go back to desired afr, then spike lean again, I have no idea why. The strange thing is this only happens in the lower gears (1-3) and its worse in 1st gear hence why i thought it could be the esp messing things up. Does this look like a hardware issue or something in the tune? I've just installed a walbro fuel pump but still had this issue (not as extreme) with the stock pump but I was running less boost with the stock pump. Any input would be appreciated

unknown fuel cut.llg

[Adamw]

I dont think it is tune related, the commanded pulse width doesnt change where it starts to go lean, it only drops a little after it goes lean due to the MAP dropping away.

There could be many causes - it could be some hardware issue such as a blockage or intermittent pump/regulator or it could be something like an electrical connection.  I would start by trying to isolate some of those possibilities.  Depending on what sort of tools or equipment you have available, a fuel pressure sensor or even a temporary cheap analog gauge hooked up would help point you in the right direction.

[lito]

Think i figured it out. Fuel pump was cavitating and sucking in air. Filled the tank to the brim and she runs sweet. Weird that it was doing it with the stock pump too. Thanks for your help guys