I used to have a buzz get my buzz back...

BlueSwede · Post by **BlueSwede** » 03 Feb 2009, 05:20

These questions may be related not sure.
I swore my fuel injection used to buzz, I have 1985,244, Lh2.2
Dont they usually buzz?? Clogged fuel filter? fuel pressure regulator? Thing is she is running better than ever. Starts fine, runs fine, idles fine, maybe a little pinging at top speed.

I just replaced the wiring on the large gray connector box on the firewall, the first three inches from the connector were badly deteriorated. Found when I pulled back the "protective" covers. looks like wires could have been touching inside the loom.
Could i have fried something? where do those four -five wires go/start/ terminate??Which components should i be concerned about?Does it have to do with the fuel injection?
plus i had an extra wire, I think it was green and red male connector side, not coming from the fire wall.Any ideas??, am i missing an important component??.

I just wanna get my buzz back....
Thanks

Kmaniac in California USA · Post by **Kmaniac in California USA** » 03 Feb 2009, 07:37

A buzzing fuel pump when you turn on the ignition key means that the pressure in the fuel rail has dropped below the preset pressure setting of the fuel pressure regulator. The pump will run (or buzz) until the pressure builds up again.

Having said that, if you turn on the ignition key and the pump does not buzz and the car starts and runs fine, then the fuel pressure in the fuel rail did not bleed down and no priming from the pump was necessary. This is not an uncommon condition and is not an indicator of a problem with the fuel system.

BlueSwede · Post by **BlueSwede** » 03 Feb 2009, 20:13

Would the pressure in my fuel pressure regulator not dropping be the cause of quick starts? sometimes it starts very quick, like as soon as i turn the key..not even a "one count", i'm not complaining but i've learned things go bad usually after they go real good..
So does anyone have the pin designations on the gray box, origin and termination points?

I thought the injectors buzzed aswell??.

Kmaniac in California USA · Post by **Kmaniac in California USA** » 03 Feb 2009, 20:31

Injectors don't buzz, they click. But on a four cylinder engine idling a 1,000 rpm, the sound of four injectors operating together at 2,000 clicks per minute will sound like a buzz.

If you are worried about your fuel regulator, just put a fuel pressure gauge on the fuel rail and see if it is regulating to specification.

I have owned my 740 for over four years now and very rarely does the fuel pump buzz before I start it.