hi hope somebody can help, my gt is over fuelling really bad (used half a tank in 2 days probs bowt 40 miles use) and seems to idel rough. i took it to my local vw specialist garage who did diagnostic and seems to think the afm,air temp sensor, blue temp sensor, and lambda sensor are all faulty bringing up faults.

air temp sender code 00523

coolant temp sensor code 00522

air flow meter code 00552

lambda probe code 00537

lambda control code 00525

I've noticed the earth on the lambda sensor is snapped could this be the reason for the lambda sensor bringing up the fault code ?

The car runs fine when you drive it just rough when ideling and drinking loads of juice, the afm seems to be working when you open the throttle the spring moves in the afm unit and all seems to be working.

I'm just trying to work out weather to replace everything listed or weather there trying to pull a fast one on me so any info is welcome and be much appreciated cheers mike.

Lambada sensor needs a very good earth to work properly so will be the main issue, rewire that and see what happens.

The ECU's on mk3's are very basic and those "faults" could have just been caused by that item being unplugged.

Erase all faults and see what comes back, the snapped earth on the lambda will bring a code up, fix that and then run a seperate earth from the battery to that earth point for good measure.

Id replace the coolant temp sensor or at least ckeck it (the resistances of what it should be at certain temps are knocking about on this forum some where have a search).

Also check your timing with a timing light, they have to be done in quite a specific way (theres a how to in the FAQ)

Then if its still running rich get it on a gas analyzer and have a play with the co screw on the AFM.

Lambada sensor needs a very good earth to work properly so will be the main issue, rewire that and see what happens.

The ECU's on mk3's are very basic and those "faults" could have just been caused by that item being unplugged.

so if i was to unplug the sensors listed them codes would ping up.my understanding of the diagnostic machine is that they show a code indicating to an area where the sensor is so in theaory they only indicate the area of the fault and the fault could pretty much be anyfing within the area sensored. Is this correct ???

I'm finkin deal with the lambda earth and this may sort the over fuelling and replace the air temp sensor this might be the reason for the rough idle.

any advice on how to check the afm is working correctly I've tryed unpluging the afm while the engines running and the engine cuts out so it must be working.

thats what i expected them to do wack it on a gas analyzer and adjust the co screw but he said he would be able to do this until the rest was sorted

yea adjusting that would be pointless with out at least getting the lambda sensor sorted, and tbh a diagnostics machine is useless on these, much better to just have a multi meter, also check your thermostat cause if thats jammed open it takes for ever and a day to warm up and it runs rich as fook trying to warm it up.

Heres a link to the FAQ lots of info on basically everything you need to know :)

http://www.clubpolo.co.uk/forum/index.php?...er=all&st=0

If you unplugged it with the engine running then thats where that fault code came from. same happens if you unplug the dizzy plug, the ECU remembers even ddo the problem has been solved.

TBH I'm suprised that the VW specialist actually had the adapter for the Diagnostic plugs, most wont touch them as there 2x2 and not OBD.

I would replace the coolant sensor as those are a pretty common problem and tend to die randomly.

how would i erase the memory codes i kow how to do the coolant temp is it the same principal for all sensors unplug it rev it through 3000rpm 3 times then pug back in and turn off ignition ???

well the two plugs under the passenger dash where left hanging out so do believe its been on the machine. I'm going to repace coolant and air temp sensors and earth the lambda see what happens if i disconnect the battery will it reset the ecu ???

how would i erase the memory codes i kow how to do the coolant temp is it the same principal for all sensors unplug it rev it through 3000rpm 3 times then pug back in and turn off ignition ???

well the two plugs under the passenger dash where left hanging out so do believe its been on the machine. I'm going to repace coolant and air temp sensors and earth the lambda see what happens if i disconnect the battery will it reset the ecu ???

hi all I've changed the blue temp sensor and I've wired up the lambda sensor earth but the idling seems to have got worse and now the car dies wen i pull away in first gear and then slowly powers away its fine wen it gets going its really hurting my head now any help very very very welcome

how would i erase the memory codes i kow how to do the coolant temp is it the same principal for all sensors unplug it rev it through 3000rpm 3 times then pug back in and turn off ignition ???

well the two plugs under the passenger dash where left hanging out so do believe its been on the machine. I'm going to repace coolant and air temp sensors and earth the lambda see what happens if i disconnect the battery will it reset the ecu ???

hi all I've changed the blue temp sensor and I've wired up the lambda sensor earth but the idling seems to have got worse and now the car dies wen i pull away in first gear and then slowly powers away its fine wen it gets going its really hurting my head now any help very very very welcome

i think i have solved the problem fitted a new afm and the idling calmed down slightly so i unplugged the lambda probe and the car spluttered for a sec or so and picked up and ran pretty tidy i now believe that all the sensors mentioned above was infact faulty so just need to fitt a new lambda and adjust the co screw accordingly and the car should run alright cheers every 1 for your help