VR6 0 Posted December 14, 2002 MFA works completely apart from the MPG always displays as 99.9. I think it's likely to be a problem with a sensor somewhere....but where? Cheers Quote Share this post Link to post Share on other sites
ross.taylor 0 Posted December 15, 2002 MPG on mine went crazy a while ago. Reporting higher and higher mpg untill was 99.9 (all during a several hour mway journey), but within several days of pootling about it came back down again. My MFA constantly reports -40degrees outside temp! A knackered sensor I'm assured. Easy to replace?? Quote Share this post Link to post Share on other sites
VR6 0 Posted December 15, 2002 Pretty sure it will be a sensor but I'm just not sure where it is! It sounds like your sensor went as you were actually driving, hence the MPG gradually getting higher. Quote Share this post Link to post Share on other sites
dazzyvr6 0 Posted December 15, 2002 may be in the airflow meter Quote Share this post Link to post Share on other sites
ross.taylor 0 Posted December 16, 2002 I was told (by a questionable source) that the sensor is "just behind the front bumper". Quote Share this post Link to post Share on other sites
G60DEE 0 Posted December 18, 2002 I'm pretty sure that the sensor behind the front bumper is the outside temperature ?! My M.F.A does exactly the same as yours VR6, just sits there from start up on 99.9, but everything else works. It will be interesting if anyone can come up with a solution. :? Quote Share this post Link to post Share on other sites
VR6 0 Posted January 12, 2003 Anyone have any idea on what to check for this problem??? Darren? Quote Share this post Link to post Share on other sites
2cc 0 Posted January 16, 2003 Guys and gals you will be pleased to know that I have chased these problems before, though both of them on me 16v. The outside air temp sensor is fitted inside the front end of the brake cooling duct on the driver's side. Can't remember now if its on the top or underside, but the sensor just plugs into a wee metal mounting plate fixed on the duct. You don't have to remove the duct, just uncouple the connector and wiggle the sensor free. It is a simple matter to check that the loom wiring and MFA is working OK. With the sensor connector disconnected, turn on the ignition and check the MFA readout. Then short the connector pins together and check the MFA reading again. The memory is a bit hazy, but I think you should get "0" in one condition and "-40" in the other condition. If these are OK then the sensor is definitely a goner. Be warned that VW changed the sensor somewhere down the years, so make sure you keep the old one coz it has the part number on it. I'll get under mine tonight and confirm these figures for you tomorrow (and the price). The MPG at 99.9 is more of a bugger. Bear with me, this next bit may be of use to other 16vers. The instrument cluster on the 16v has a vacuum sensor mounted in the back of it fed via a tube from the engine bay. Sometimes the tubes get chafed and spring a leak (if you're lucky), but more common is the sensor failing. This cost me £125 for the part in Jul 2000. You can easily change this yourself but be careful and don't bash it about. Take the whole cluster out the car, remove the clear screen (two screws) and you can then get at the fixing screws for the sensor from inside. You may find it easier to get at by removing one of the main instruments (a couple of fixing screws) but again be careful when separating the instrument's electrical connector from the circuit board - the clusters ain't cheap. Anyway, I took the cluster out of the VR6 to check this out and found that this cluster just has an electrical connector on the back. So I can't shed much more light on this right now, but I'll see what I can discover. Don't go away........... Quote Share this post Link to post Share on other sites
Pau1 0 Posted January 16, 2003 Yeah Spot on... The most common fault for the MFA's MPG is the vacum hose that attaches to the back of the instrument cluster. Either it's not on, or it's got a leak. Paul Quote Share this post Link to post Share on other sites
VR6 0 Posted January 16, 2003 Ok cheers 2cc and paul........gives me something to investigate.......although I'm not sure that's a good thing! :) Quote Share this post Link to post Share on other sites
2cc 0 Posted January 16, 2003 More on the air temp sensor. Just checked on mine for the test readings you should get. Easiest way to reach the sensor is to lie on the deck accross the front of the car head to driver's side, stick your arm up behind the bumper and you can then feel the cooling duct; the sensor is on the top right at the front. With plug disconnected and ignition on the MFA should read "-40"; if you want to check the voltage at the plug it should be in the order of 3.2volts; with the pins in the plug shorted together the MFA should read "+50" (tho' doesn't actually show the + sign). If all OK then the sender is duff. As I said b4, check the part number coz VW do more than one. They look identical 'cept for the number and have different resistrance ratings - means you'll get the wrong temp readings if you fit the wrong one or may not work at all. My 16v is a '90 and the number looks like 171909 2724 but the last bit is scuffed so can't be certain. Hope that sorts ya mate Don't all laugh but in the middle of that my just fitted Kenwood mask head unit has just died and frozen open. :cry: If its not one thing its another! Quote Share this post Link to post Share on other sites
Andi 2,147,483,647 Posted January 16, 2003 Don't all laugh but in the middle of that my just fitted Kenwood mask head unit has just died and frozen open. If its not one thing its another! Ah, one handy thing in having a manual Kenwood mask :) Thanks for all the great temp. sensor notes - mine hasn't worked since I bought the car, so will be good to finally get it working :) It does occasionally work... so might try cleaning it up and reconnecting it all. Nice one, Chris. Quote Share this post Link to post Share on other sites
2cc 0 Posted January 17, 2003 Kenwood auto mask unfrozen - one likes to keep ones hands free... In case anyone else suffers from this, after dissing the power, trying the reset etc it turned out that one of the car loom side speaker wires had just decided to come loose at the connector block. Once pushed firmly home (ooh er mrs) the thing came back to life. Happy bunny :) Quote Share this post Link to post Share on other sites
G60DEE 0 Posted February 6, 2003 Thanks for the 99.9 MFA help will get that sorted this weekend! :) Quote Share this post Link to post Share on other sites
dragon green 5 Posted February 24, 2013 Holy thread revival ! Some good info on ambient temperature sensors, It didn't sort mine, But mine reads exactly 40 degrees too hot ! I've now got 4 sensors,and infinite patience ! Quote Share this post Link to post Share on other sites
destructiv dave 0 Posted February 24, 2013 Holy thread revival ! Some good info on ambient temperature sensors, It didn't sort mine, But mine reads exactly 40 degrees too hot ! I've now got 4 sensors,and infinite patience ! Bryan - in this weather, surely you don't need the MFA to tell you it's cold. For me the frozen puddle in the passenger footwell tells me what I need. Quote Share this post Link to post Share on other sites
dumptyboy 0 Posted February 24, 2013 My mfa reads 99.9 miles on my VR,(K reg 1993, coil pack) I've checked all the wiring and connections on the rear of the cluster put it still reads the same. Is it connected to one of the sensors on the thermostat housing? I've changed the blue temp sensor, but that made no difference either! Any help appreciated. :) Quote Share this post Link to post Share on other sites
renson 0 Posted February 24, 2013 Whats this pipe on the back of the instrument cluster? i've never even seen one on my car! should there be something else on the back of mine apart from the cluster connector? Quote Share this post Link to post Share on other sites
Supercharged 2 Posted February 24, 2013 10 year thread revival! The pipe is the vac feed from the engine for the MFA Quote Share this post Link to post Share on other sites
renson 0 Posted February 24, 2013 I have never even noticed one. Its not there if it should be! Is that for all Corrados? mines a 95 16v. A nyone got a pic so i know what to look for? Quote Share this post Link to post Share on other sites
