I seem to be lacking power lately, thinking the MAF would be the first place to look I disconnected the wires to it and took the car up the street for a little test. There was no noticable difference with the MAF disconnected, if the MAF was ok would i have noticed any differences or can i presume the MAFs had it?
I had the dealers run a diagnostic check whilst it was in for the bearing arm recall last weekend and they said there was no fault codes.
Anyone any ideas?
Cheers
Jim
MAF Failure?
Jim
One of the local dealers told me last year that there were no fault codes when I was convinced my MAF (no. 2 I think!) was shot. My performance was down (it was then 326bhp but a failed MAF meant that it was only as quick as my wife's TT) and the economy was much improved (nice but nearly 30mpg couldn't be right!). I had also had lambda probes changed.
Worth a trip to a 'proper' specialist. I am on MAF no. 4 now and keep a spare!
HTH, rgds
Simon
K04's, Tanoga, H&R, full Milltek, Forge DV's and Samco TBB&F!
One of the local dealers told me last year that there were no fault codes when I was convinced my MAF (no. 2 I think!) was shot. My performance was down (it was then 326bhp but a failed MAF meant that it was only as quick as my wife's TT) and the economy was much improved (nice but nearly 30mpg couldn't be right!). I had also had lambda probes changed.
Worth a trip to a 'proper' specialist. I am on MAF no. 4 now and keep a spare!
HTH, rgds
Simon
K04's, Tanoga, H&R, full Milltek, Forge DV's and Samco TBB&F!
Yep, no. 4!
1st lasted 35K miles and I ran it gently with duff manifolds too for another 2K until it was changed, 2nd 6K, 3rd 247 miles !, 4th 2K so far...
Numbers 1 and 2 failed causing performance to drop, 3rd was really exciting causing it to overboost and go to limp mode. Much preferred 1 and 2 as 3rd failed in roadworks, heavy traffic and at night on M11!!!
Rgds
Simon
K04's, Tanoga, H&R, full Milltek, Forge DV's and Samco TBB&F!
1st lasted 35K miles and I ran it gently with duff manifolds too for another 2K until it was changed, 2nd 6K, 3rd 247 miles !, 4th 2K so far...
Numbers 1 and 2 failed causing performance to drop, 3rd was really exciting causing it to overboost and go to limp mode. Much preferred 1 and 2 as 3rd failed in roadworks, heavy traffic and at night on M11!!!
Rgds
Simon
K04's, Tanoga, H&R, full Milltek, Forge DV's and Samco TBB&F!
You wont get a fault code when the Air Mass Meter is contaminated. You have to look at MVB and boot it down the road to see if its faulty. ECU thinks it IS outputting the correct values even when its not so wont flag a fault.
Look at it like this. The ECU has fixed values (map) to operate from. say voltage upto 5V on a sensor circuit.
Below 1V and above 4V readings are used to tell ECU there is a fault on the circuit. This is how you often get short to pos or short to neg fault codes. i.e if the plug is disconnected or the wires are shorting out.
Anything between 1V and 4V is seen as a correct signal output from the sensor and wont flag a fault.
(The 1V and 4V values are for simplicity and are not actual)
When the Mass Meter becomes contaminated, it reduces the signal output, but as it is still within the range, no DTC is logged.
Look at it like this. The ECU has fixed values (map) to operate from. say voltage upto 5V on a sensor circuit.
Below 1V and above 4V readings are used to tell ECU there is a fault on the circuit. This is how you often get short to pos or short to neg fault codes. i.e if the plug is disconnected or the wires are shorting out.
Anything between 1V and 4V is seen as a correct signal output from the sensor and wont flag a fault.
(The 1V and 4V values are for simplicity and are not actual)
When the Mass Meter becomes contaminated, it reduces the signal output, but as it is still within the range, no DTC is logged.
Who is online
Users browsing this forum: No registered users and 87 guests