The following applies to the 2008 through 2013 EVO X and 2009 to 2013 RalliArt. It has been known for quite some time now that the fuel pump relays are complete crap in the EVO X and RalliArts. Swapping out to the better blue fuel pump relay is included with a dyno tune here @ RRE.
I had a 2010 X come in for a tune last week. The car had basic mods just installed so it should have been good for a “before” pull as-is on the dyno. After the before pull I’ll put in a 3 port solenoid and do the blue relay swap at the same time. Before the full pull I tipped into the throttle at 3500 rpm to check boost and AFR. It was super lean almost 12:1 afr. For a drop in filter and cat back exhaust it should have been high 10s or low 11s at least.
So I went straight for the fuel relay and swapped it with the blue one. AFR went right back to where it should. Bad black relay caught red-handed. So I figured cut it open to see what exactly is going on in there.
Cut open relay:
Lever assy that the coil pulls sideways and pushes down on the contacts:
I can only guess someone had the bright idea to make a low profile relay by laying the coil on its side. When energized it pulls a lever sideways that pushes down on the contacts. Read the rest of this page »