hi driving back from town today with some more bits for my 3a conversion and i was doing about 70 behind a car on the dual carriage way, they pulled in so i put my foot down to get passed. now whereas the turbo normall kicks in and you shoot past, it felt like i had now power at all i pulled in to a lay by and popped the bonnet, reved it etc everything sounds and looks ok. set off again and still the same, struggling to get to 60 and taking ages. now usually with the window down you can clearly haer the turbo spinning up and down and the recirc dump valve going, but now there is no turbo or dv sound at all the car is still under the garage warranty thank god, i've rang him and he was going on about the airflow meter or something and its an easy fix. this is fair enough but is there anything else that would give these symptons?? i don't want to go there then him botch something that'll go when the car is out of warranty forewarned is forearmed etc anything i should look out for or make sure he renews?? what happens if the turbo goes tits what symptoms do you get then?? cheers for your you time Chris
sounds like common fault,mass air flow sensor has gone,but get it on a computer that should tell you what it is for definate
try the olf fairful disconnect the airflow meter, leave it unplugged and the give it a drive if its the airflow meter is will go like it should as the ecu goes to a default value that will work lol if it is still kack then is needs more investigating
just took it out again and its back to normal???? does that point to it being the sensor?? i don't have a manual for the mk4 as i get everything done at vw as i want to keep the stamp up, whereabouts is the sensor mate? a pic would be a godsend cheers Chris
should be just after the airfilter housing, block connector with about 4 wires coming out of it if as you say its ok now tho i'd have to say it might poss be something else and not AFM
Hi, Just thought i'd resurrect this thread. My sister is having the same problem on her Mk4 GT Tdi 150. It was down on power all the time, so i replaced the mass air flow sensor and now the problem is intermittent. It's fine 80% of the time but then will suddenly lose power again. If I pull over, turn of the engine for a minute or so then re start the engine, it usually cures the problem. Does anyone have any idea where i should start? I'm planning on getting it VAG COM'd but last time i did this, it didn't even show up the faulty mass flow sensor. Please help!
could be a vac line fault to the turbo, split and causing overboost which the ecu see's and stops the turbo output, turning the ign off and back on resets the overboost fault and the turbo works as normal untill it sees overboost again and cuts the turbo again
or the opposite, a simple boost leak. the computer doesnt the correct expected/actual boost figures so goes into limp mode until you floor it again egr valve sticking will causes it too
glad im being taught dude but if you read what he says he has to turn the ign off and restart the engine before it works again, also he says it drives fine then goes faulty, if there was a boost leak then there would be a fault right from the off as there would be no boost
No, I think you've missed my pointing out of the humorous irony here! By using analogy,...there would be great amusement in me trying to tell Stephen Hawkings about physics!
My friends turbo stopped on his mk4 tdi and as said here I thought it was MAF fault, so drove it down to gsf (slowly ) and the guy let me just put one on to see if it cured it, without buying it. In this case it did! it was the MAF located on the inlet hose bit on top of the engine, i think it was 4 scews and the connector... just a thought. 55 quid IIRC.
in the end this fault was a pipe hanging off the turbo, not sure which one and i was told by the mechanic via the missis so could of been any one. we got the maf changed under warranty by the garage we bought it from, the fault seemed to clear for a while but then strangely reappeared. we had it booked to go in for another look, but when we had it serviced at a local garage we use, and they noticed that a pipe was off, reconnected and its all sorted now. hth Chris
i had a 130pd where the rubber pipe going from turbo to intercooler split, the first i knew of it was it going into limp whilst acclerating past 80mph i pulled over, re started the car, it worked fine until i put my foot down then it went limp i found the boost leak due to the black diesel engine oil coming out the split i then found out that the ecu gets a figure for actual boost and compares this to expected boost. if they are different for long enough it goes into limp thought you geniuses would have known that
some of us geniuses do lol, some just have to read about others experience's boost leaks happen from the off tho usually, not at 80mph onwards either way i hope you get it sorted kalden
