Technical MAF Sensor and limp mode -explanation?

[Mauro Malvezzi]

Hi everyone,



I did a bit of reading here on the forum in preparation of the next issue to solve on the multipla, the dreaded "won't rev past 3000 rpm". At first, I thought it was the MAF sensor (as per suggestions here), so I replaced it. Issue did not go away. I just ordered the kit needed to read the ECU codes thanks to Multiecuscan, so I'll be updating the thread shortly.

In the meantime, I'll try with your help to try and guess the issue?



1. The car has the engine fault light on

2.The MAF is brand new

3. The car will NOT rev past 3k rpm, and therefore enter limp mode, as long as the MAF connector is plugged in.





If I disconnect the MAF sensor, the engine light stays on, but the turbo kicks in andthe engine revs up to whatever it's capable of.



Therefore, the bits actuating the turbo (solenoid, vacuum, MAP) must be fine.



What can the connection be with the MAF, that explains such a behaviour?



Thanks in advance guys!



Mauro

 

[bugsymike]

The ECU has a stored "fail safe " setting which it uses under those circumstances.
By the way and may be unrelated , but some years ago I had a 05 Doblo 1.9 JTD that had the Maf disconnected on purchase , when connected it chucked out loads of black smoke, new MAF didn't cure it .
The problem was the wiring plug wires had broken a few mm from the socket.
It had done 220K miles though.

 

[Mauro Malvezzi]

Dear Mike,

I shall check the wires, and yes, apparently the stored failsafe settings are what makes the engine work as it should - I am told it's however "no bueno" to drive with the MAF disconnected all the time.
I will update the thread with the results of the Multiecuscan readings.
Thanks for chiming in!

 

[bugsymike]

Dear Mike,

I shall check the wires, and yes, apparently the stored failsafe settings are what makes the engine work as it should - I am told it's however "no bueno" to drive with the MAF disconnected all the time.
I will update the thread with the results of the Multiecuscan readings.
Thanks for chiming in!

Yes, whilst a get you home "fail safe "setting it is only that.