Su un sito ho trovato delle indicazioni sul fatto che anche se sono momentaneamente interscambiabili i reley possono creare qualche inconveniente e nello specifico suggerisce di usare i codici corretti per la presenza di piccole differenze.
http://www.thirdgen.org/techboard/tp...nces-they.html
riporto il testo nel caso svanisca la pagina in futuro:
Just informational...
It's repeated many times that the MAF power and burn off relays can use the same part. Well not exactly.
The MAF power relay has a couple added resistors to it that the standard 5 pin relay does not. You can see one of them in the inserted picture. There is also another resistor under the coil that you cannot see.
In the picture an original MAF burn off relay is on the left and an original MAF power relay is on the right. The added resistor is obvious.
If they were really interchangable GM wouldn't have made the modifications to the MAF power relay. They would have just thrown in a standard 5-pin relay. Also the aftermarket would have been the first to jump on that as their primary motive is to reduce part numbers.
Now the fuel pump relay and MAF burn off relay can be used interchangably but there are differences but not enough to cause an issue.
The correct GM part numbers for the relays are. GM Borg Warner and GP Sorenson.
GM 10067925 MAF power
GM 10094701 MAF burn off
GM 14078914 Fuel pump
BW R3009 MAF power
BW R671 MAF burn off
BW R761 Fuel pump
GP MR22 MAF power
GP MR82 MAF burn off
GP MR5 Fuel pump
My TPI has been doing some goofy things and it was at the time I did the swap and replaced the relays. I dug out the old relays and checked the current part numbers. Since the MAF power one was not the same number I needed to open it up and find out why.
I had always thought that the GM relays were pretty much one of two types 4 terminal or 5. After a little research they are minor differences in some applications. Yes any 5 terminal will work in pretty much all apps but they may not be exactly right and could cause issues due to missing internals.
Well after putting the correct power relay in my goofy issues have been solved. So make sure you buy the right relay.