Golden

iTrader: (1)

I was at my local Mitsu dealer getting some parts and decided to grab a spare blue relay. (Never know when a local customer has a bad relay and needs it replaced right away.)

I showed the parts guy the part number and said, "do you have one of these?" He was like, "that is a blue realy, right?" LOL! The part guy knew the part number by heart. He said they had lots in stock. I guess they've sold a few.

Thegame

iTrader: (26)

I wonder what the ones that rattle look like... I remember when my 08 started to rattle, but electrically it checked out okay. I didn't take any chances and swapped it out in fear. It's easy to use a meter to check these relays. I hooked up a small 12Volt 7 Amp-hour battery to the coil and it still energized the contacts. (Or you could just hook it up to the car battery, but be careful in case it's shorted.) I saw very little resistance (a good thing) across the contacts. You could also just check the resistance of the coil. Compare it to a good coil on another relay. Something like 86 ohms or maybe 86K ohms. (Can't remember what scale I was using.) The pitting is pretty much unavoidable and happens on all electrical contacts. They are actually coated with silver or some kind of metal. Sanding any contacts is not a good permanent fix. You take away the silver coating and then it will pit again, far more quickly.

I don't understand why, that on something this vital, Mitsu didn't use a NC (normally closed) contact / relay. Energize the coil and open the contacts in low fuel / boost pressure mode. De-energize the coil and allow the contacts to go to their normally closed position on high fuel / boost mode. At least this way, when a failure does occur, you still have full fuel flow. You just run rich and lose power, etc... Far better than the current way that when it fails, you run lean and potentially damage your engine. I'm a just a technician and not an engineer, but come on... Even $100 motors and circuit boards have safe setups for when a failure does occur.

merlin.oz

Good investigation Mike.

A possible additional safeguard could be to solder a 0.1uF capacitor across the contact pins on the back of the relay cradle, a-la dizzy points for old school guys.

Or maybe just relpace the dammed thing every fourth oil change...

Zeitronix

iTrader: (2)

Fuel pump pulls 10A -15A of current. That's a lot of DC current for a relay to deal with.

AC current is way more forgiving since there is 0 crossing by nature. DC is ... DC so full blast all the time and lot's of arcing across contacts.

The black relay does not "look" to be rated for 10-15A current. We do not have manufacturing specs here for a given model but based on experience what I see on those pics does not look rated for the job. Not only contacts are small, smaller coil requires smaller spring to pull contacts fast. Fast action = less arcing. Big contacts needs big spring, big springs needs big coil.

Upgrade and ASAP.

tephra

iTrader: (6)

So I experienced this first hand last night on the dyno.

From run to run we would get different AFR reading (13:1 vs 11.5:1) - at first we thought it was a wideband/exhaust problem so we hard-wired the wideband pre-cat instead of sticking it in the tailpipe..

After it kept doing it I had a brainstorm and checked the relay, it was black and sounded like sand when shaken. I changed it out for the green one and immediately the AFR came good..

Obviously we always knew the relay was a problem but to see it first hand is always nice

murlo26

iTrader: (9)

A quencharc or snubber would prolly help I would agree but it shouldn't be required.

I agree with using normally closed contacts as well for this. Fail safe wiring ftw, not sure why the hell it wasn't like this.

jsmits2689

This thread helps a ton. Just got a Evo X and noticed I too still have the black relay. Going to the dealership to get a few blue ones

Wraiths_Zero

iTrader: (3)

I'm gonna go and switch mine out asap but just to clarify the dealership wont do this for free will they?

murlo26

iTrader: (9)

They might if you make a stink about it. It is like $40 bucks to replace them all and like 5 mins to pop the hood locate the right ones and replace. It's pretty straight forward lol.

Mike W

iTrader: (1)

Another EVO X came through the shop with a dead relay. This one made a slight noise when shook. As if there were a couple grains of sand inside. Nothing I would describe as a "rattle". This car had been tuned back in late 2008 before the relay was a common known possible problem. It still had the original black relay in it and the customer was complaining of a sputter under boost. Changed the relay and everything is fine.







Not much electricity was going to flow through that connection :-P

Mike W

TURBO X GSR

kinda new here but what are the other ones i need to replace and how many ?

Chaz17

iTrader: (11)

i hope my dealership is like this

so without considering the price aspect, whats a better idea? blue or green? i only have some simple bolt ons. nothing big.

ITLL_GO

Great thread, I was on the dyno on Saturday and after a a couple of runs the AFR was starting to lean out around 5000 rpm and up. So we put the stock tune back on and still same issue, so we tried swapping the relays but the wrong ones so the result was the same! So now I am going to see if I can get one here at the local dealer and try again.

migs647

iTrader: (19)

^--- Interesting. I believe that's the first I've heard of a relay hurting the stock tune

Noize

iTrader: (24)

Mike, I missed these back in the summertime, but thanks for the uncapped pics and explanations. They are great and helpful!