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73-87 Chevy _ GMC Trucks => Performance => Topic started by: lnydam on March 13, 2015, 10:23:45 pm

Title: MSD atomic EFI with dual tanks
Post by: lnydam on March 13, 2015, 10:23:45 pm

I'm putting MSD atomic EFI on my 87 with dual tanks. On the MSD wiring harness, there is one wire that needs to go to the fuel pump. I'm not totally sure where I would connect that wire to, but i'm guessing it would go to pink wire on the dash mounted fuel tank selector switch that comes from the ignition. Anyone know if this is correct?

Title: Re: MSD atomic EFI with dual tanks
Post by: Irish_Alley on March 14, 2015, 12:57:57 am

i would set it up off a wire on the fuel pump relay
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=30539.0;attach=28691;image) (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Fuel_Emissions/X8736_1987_GMC_Light_Duty_Truck_Fuel_and_Emissions_Including_Driveability.pdf#page=94)
click the picture for the manual if you need to

Title: Re: MSD atomic EFI with dual tanks
Post by: Captkaos on March 15, 2015, 01:31:46 pm

The factory setup on a TBI engine is for the ECM to signal the relay to turn on the pump.  The switch determines which pump.

Title: Re: MSD atomic EFI with dual tanks
Post by: lnydam on March 16, 2015, 12:34:40 am

Ok Thanks for the help

Title: Re: MSD atomic EFI with dual tanks
Post by: lnydam on March 16, 2015, 01:29:12 am

So I found a more complete diagram, what is a fuel module, and where is it located on the truck? Does my truck even have one?
so many questions.

Title: Re: MSD atomic EFI with dual tanks
Post by: Captkaos on March 16, 2015, 12:43:55 pm

Your truck won't have a fuel module unless it is a 1Ton truck.  Not sure since you didn't say...

Title: Re: MSD atomic EFI with dual tanks
Post by: Irish_Alley on March 31, 2015, 07:04:00 pm

just for future reference the location of the module on the 1 ton
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=23798.0;attach=19861;image)