punker 0 Posted October 24, 2007 can some one tell me what the electrical connector is for that is located on top of the air flow sensor/air filter box? i've disconected it and my very hesitent 16v works better when warm. It's a bit dodgy on start up through. Quote Share this post Link to post Share on other sites
davidwort 0 Posted October 24, 2007 There's more than one, but if you un-plug them all the ECU will run in default settings, rather than adjusting fuelling etc for the correct temperature. It seems that a dodgy lambda sensor giving incorrect readings to the ecu will cause bad running and stalling which can then be partially eased by forcing the ecu into 'limp-home-mode' in this way. Quote Share this post Link to post Share on other sites
punker 0 Posted October 24, 2007 thanks i have tried unplugging the lambda probe (with other everything else connected) and this made no difference, it was still very hesitant. also noticed that the fan dosnt come one when engine is hot (oil/water temp above 110deg), could it be a temp sensor? Quote Share this post Link to post Share on other sites
davidwort 0 Posted October 24, 2007 the fan switch isn't connected to ECU, you can test it off the car by heating it and making sure the two circuits/paths switch on as the temp rises, they do give problems when they are old, also check your fan works on both speeds by directly connectinf it to the battery. There should also be another small single pin connector oin the front left of the head that switches the fan on if under bonnet temps get too high, make sure that is present and connected, they often get missed off or left unconnected, won't cause running problems though. I was told once that on the 2.0 16v you need both sensors on the metering unit disconnected to get the ECU to run in limp-home-mode, I'd suggest you get the ECU cehcked with VAG-COM or similar to see if there are any fault codes first. Non-VW lambda sensors, particularly 'generic' ones are known to cause problems too. Quote Share this post Link to post Share on other sites
punker 0 Posted October 24, 2007 ok thanks for your help. i'll check the fan switch and the other connector. Looks as through i'll have to get a new lambda probe (GSF have one for around £30) and find someone with a VAG-COM. can you buy a VAG-COM? might be worth it if there not too expensive? Quote Share this post Link to post Share on other sites
