Flat battery because FUEL relay stays ON! -> PROBLEM SOLVED!!
 

Hi all

I have been having this random flat battery issues. With random I mean that the car could have no issues what so ever for a week but ended up with a flat battery next morning .

Measuring the dark current, even monitoring it over several hours, showed nothing strange. OK the dark current on my car, 90mA, was a bit higher then the 50mA Mazda mentions, but surely not enough to drain the battery overnight.

Some time passed... I changed the battery with a new one and the car was fine ...for about 7 days

I started all over and started monitoring the dark current. Couldn't find a thing wrong until this afternoon(!) I measured again and saw a current of 1.8 amps !!! I was so happy LOL finally some sort of starting point...

I started with removing the room fuse, etc... nothing changed...

When I disconnected the battery I could hear a "click".. (sounded like a relay!)

To make a long story short,I traced it and it seems the FUEL relay stays on !

I changed the relay, same issue.

When I disconnect the battery, as mentioned, I hear the relay disengage and when I connect the battery again, the relay stays off!

Did anyone else had this issue?

Cheers

Steve

I've never heard of it. Good troubleshooting so far.
page 24 of the electrical section of the manual seems to show two relays for the fuel pump.
http://smrmicro.com/rx8servicemanual/

No, Ive read most of the post for for years.. Never heard of it.

..
 

Thanks for the reactions guys, I will take a look at the manual in the link :)

Fuel relay
 

I downloaded the manuals :D: .

Fuel relay -> whoopsie -> goes to PCM .. grrr..

Ok, so it seems the time has come to put a relay between the juice going to the Interceptor.... and the 12V -> ignition key...

I'll post my findings....

Problem Solved!!!
 

No more flat batteries thanks to a relay between the Interceptor EMS!!

So it is a fact that the Interceptor triggers the FUEL relay (combination af GPS screen ON/OFF, HEATING ON/OF, RADIO ON/OF) drawing about 1.8 amps !

But as said .. problem solved !!! ANd that is all that matters ! :eyetwitch

Good work dude! I had to replace my battery last month--i was also at the time running the int x
oscd

so:

interceptor X + RX8 = dead car batteries?

Love to see somebody else with an INT-X repeat this experiment concerning the fuel relay.
I'd also like to see the current draw with and without the X with everything off.
I sent the OP a PM, because I had read in one of the repair manuals that the off current draw should be around 20mA when measured on the negative side.....not as he listed. Anyone really know?
Oh...........wasn't sure of the terminology used.........."dark current".......... as well.

Dark current = current flow from the battery when the car is parked and off, no lights on, etc...

The original spec was maximum dark current of 20 mA, iirc, but was subsequently raised to 50 mA. That means, if you measure more than 50 mA, then something is wrong. Or, maybe you have some aftermarket part drawing additional power.

50 mA is bigger than some may realize. At that rate, 3 weeks, will drain 25 Amp-Hours from your battery. That's a pretty big hit, even for a good battery in new condition.

Thanks..........figured that was what "dark current" was, just hadn't heard that term.
Oh..........Where did you get the 50mA number?
BTW..............I went back and read my other post to someone where I actually did go look up the number and it is 20mA standard, so I changed my post above so nobody would get confused in the future.

I think I am having this very same problem. Testing Steve's theory tonight

2004 GT MT
20065 mi
Int-X ems

this has been reported before and Scott at Mazsport posted a fix. I think the fix was... it was incorrectly wired.

You'll have to do a search.

Hey SpeedSteve, what exactly did you do to solve the problem? Where did you install the new relay? I have the same problem, but I pulled the EGI relay.

What to do!
 

Hi there

Update : some time passed, and yep.. the problem is solved >..

What I did is very simple :)

I took a 12V signal (main fuse box) -> from the "Wiper" fuse to feed the relay.

When powering the 12V signal activates the relay -> the closing contact powers the Interceptor. Ignition off -> relay goes off -> power to the Interceptor goes off -> fuel relay goes off -> no more problems!

TIP! be sure to remove the fuse (+ side of the Interceptor) when you work on this. Put the fuse back in when you finish the setup to protect your interceptor!

It is all very simple, but it works great!

Cheers!

Steve

PS: If you want I can make a DIY topic about it ... (this weekend)

that would be a good thing to do.. and thanks steve. good job.


beers :beer:

Hey, I know this thread was from 4yrs ago but was hoping I could get some help. My 04 RX8 had melted wiring in several places. The engine harness was melted at the O2 sensor connector and the neutral safety switch. Also the harness from the fuse box to the dash has melted wiring under the dash. I once replace the headlight unit due to melted wiring as well.

With that said. Was having the same problem a month ago. My battery would die in a day. I took it to the dealer. To make a long story short, I just replaced my engine, as well as the engine harness, neutral safety switch, O2 sensor, and catalytic converter. Did not replace the the fuse box harness cuz it's an other $3k. When I went to pick up the car the tech told me that the fuel pump stays on when the car is turned off and it will continue to drain the battery. So he told me to disconnect the fuel pump fuse every time I not using the car and reconnect it when I need to use it. This is kinda of a hassle and was wondering how I can fix it. I don't want to have to replace the whole fuse box and harness as they suggested.

I read how you guys fixed this problem but I'm not very experienced in this topic and almost have no idea of what you guys were saying. Is there a less complicated explanation so that I can understand better?

Thanks I appreciate any feed back

I'm afraid that if you can't understand the description you might find it difficult to fix this. It will take a lot of troubleshooting to figure it out.

You could configure a relay to the fuel pump relay trigger that shuts the realy off when the ignition is off...but it isn't easy to explain how to do it if you have never done it before

If you are deturmined to do it then find a wiring diagram...and we can help you out. You will have to cut a couple of wires and splice the relay in....or find the reason for the problem in the first place. Do you have an INTx...or is the stock wiring causing this? Did you replace the fuel pump relays yet?

@Dannobre - thanks for replying.

I will try to find a wiring diagra. I'm not sure what a INTx is.
The stock wiring could be causing a shortage since I did have some of the wires melt. I don't think I have replaced the fuel pump relays.