I would like to do a quick fuel pump test and wanted to know if removing the fuel pump relay and putting a jumper wire between pins 85 and 87 will the pump run without any damage to the ecm.

 

if those are the power poles of the relay, no problem.

i jump from battery +ve to the pole leading to the fuel pump.

 

The terminals you need to 'jump' are 30/87.

85/86 are the relay 'coil' terminals.

bob gauff

 

yes Bob is correct. 30/87 are the terminals to bypass just about any of that style relay. Do the ones you said and youll smoke the driver in the ecu depending on wether its a pos or neg trigger

 

^^

That's why I weaseled on the pole numbers.

 

Don't the ECM drivers even have over current protection? Scandalous if they don't.

 

yes, its called a relay. This is why you dont go checking circuits with test lights but use a dvom. Test lights just to turn on the light can blow a driver. Most circuits now days are neg triggers from the ecu with power on the other leg. If you dont know what youre checking, you can really fubar something easily

 

Brutal -a relay with a s/c coil is a source of high current not protection against it.
The function of the relay is to switch loads too big for the on-board drivers.
It costs nothing to incorporate current limiting into an IC and if it hasn't been done the designers should be taken outside and shot.

 

thanks Steve, Im well aware of what a relay does, how it functions and its purpose. I realise you sometimes miss my tongue in cheek sarcasm

 

I promise not to have you taken outside then - we couldn't manage without you.
I thought you might need a little tutorial on relays.........................