[funny_canuck]

What type of signal is being sent from the MAF to the PCM?

If it's digital then the reason for max 5V should be obvious, considering the PCM likely uses something like TTL logic. YES, with TTL inputs higher then 5V will work but they will not do anything more. TTL devices have a tolerance and differnet voltage ranges reperesent the inputs.

I've never metered the outputs form the MAF but if they are digital then increasing voltage beyond 5 V will be useless. Varying the frequency/ pulse width would be a differnet issue.

Increasing the voltage could also have the reverse effect when you look at what is happening at the receive end of the PCM. If the input voltage is higher then designed for the electronic components in the PCM could heat up. HEat in electronics = bad performance, more power loss and ineffciencies.

Just my $0.02 on a few other things to consider.

If someone is serious about doing this sort of modification they should be looking at more then whether or not something physically burns out o doesn't turn on at a higher voltage.