Hi all ! Have recently bought a 03 golf gti 1.8t auq model. This was to use as a daily whilst working on my mk1 ! Althought it is a nice clean example, it does have some issues !! I have found that it's not always running at full potential... sometimes you can feel/ hear pressure being lost. I have checked all the intercooler pipework and no leaks. There is also not faults detected on vcds regarding pressure loss ?? Sometimes it feels like a hard boost cut ?? The car does accelerate but feels sluggish. I have read that the brake light switch can cause this, so can i test this via vcds or is it a case of just buy one and see ? My last question is regarding sai ect deleting on this specific model/ year ? Will it through a permanent fault code even with resistors ? Have been looking on various forums with no concrete answers !! So if anyone has succeeded or tried and failed could you let me know as i dont want to refit it all again !! Haha. Sorry for the long winded post ! Thanks for reading !!
if you scan the ecu measuring blocks you can check the clutch and brake switch operation, ross tech cover it nicely down the bottom of this page: http://wiki.ross-tech.com/wiki/index.php/Checking_Cruise_Control_using_Measuring_Values the best way to do it is have the sai coded out of the ecu entirely. a proper ecu expert will be able to sort this for you no problem. its factory on some engien codes, the BAM code doesnt have sai at all
On MK4 GTIs, boost loss is generally because of leaks in the charge air piping. Common areas are the Recirc valve and split PCV to manifold hoses. Brake switch and clutch switches are flags in the ECU logic, although I am not aware of them causing a limp home condition. Your EU3 AUQ engine does run a SAI system for rapid catalyst warm up and this hardware can be removed, after the control calibration is tweaked to switch off the drivers that operate the relay and pump.
Thank you for your advice ! Apparently a faulty brake light switch can cut power as it is incorporated into the cruise control wiring. Even if it is not installed on the car, or so i have read. I think this may only be the four pin switch maybe ? I have already replaced some of the vac lines, so will check the pcv pipes tonight. Maybe it's just slow haha. Definitely dont get the pinned in your seat feeling ! Thanks again, and I'll report back what i find to be the fault !
I think i have found the answer to my leaky boost issue ! Injector seals have gone ! Only noticed after giving the engine a clean. All the parts have been ordered from the local vw dealers to rebuild the inlet manifold ! My one remaining issue is the sai now. Seems anyone local to me cannot decode the sai ?? Just generic remap people using laptops. Can this be done myself using downloaded software ? Dont want to remap it myself as ive been through that with my megasquirt mk1! Im near Colchester in essex if anyone can help or recommend someone that can ? Many thanks !
