79+80+84_rx-7

84/85 Fuel pump relay trick...

Could also work on other years....

There is a relay for the fuel pump, where if you wreck, it shuts it off, or it may go bad and just shutoff the pump....

If your fuel pump stops working, do this trick, so you know its most likely the pump... If it is the pump, might as well change the filter while you are down there...

On the 84/85 12a models (at least) the fuel pump doesnt turn on until the car is started... If you want the pump to turn on when the key is on the "on" position, this trick will do just that...


Fancy Art Picture of the procedure since pictures are worth a thousand words...


Note: there is no relay, just the connector to it, and the place it was held.....


Picture barrowed from a former forum user thread, nipplebandit45


Laterz, Andrew

inittab

Good stuff Andrew! And if you wanna prime the carb, you could put a momentary switch in place of the jumper. Turn the key to "on", hit the button and tada, you're carb now has fuel.

cdrad51

For educational purposes, here's what the relay looks like.

Bob Holton

I jumped the pump from tthe coil terminal . pump comes on with the key.In case of flood just unsnap the wire till it starts

mazdaverx713b

iTrader: (91)

good read! however, whenever i turn my key to the on position, my pump kicks on........

Mr_Rx7_Au

Just an bit of a heads up.

Here, S3 Aus rx7, when the key is on the "on" position, the fuel pump does start. FYI.

Dan_s_young

iTrader: (1)

wow back from the dead... Anyways on my car I searched and searched for this but couldn't find it... So I just rewired the fuel pump and put a switch in the dash.

BTW its a 1985 GSL, So I don't know if im blind or what...

64mgb

iTrader: (1)

The relay is mounted on the right side of the steering steering column, under the under dash cover.

Rich

mazdaverx713b

iTrader: (91)

rewiring the fuel pump always seems to cause some problems. like fuel pump vooodoo.

pratch

Just install a kill switch. Most folks have aftermarket stereo systems, so the 12v always on from one of the stock amps is a good lead (and being behind the driver seat, is perfectly close to the fuel pump wiring).

Hook it up to a standard switch, put it anywhere out of site, and you're good to go. You may stall a few times after driving a few hundred yards until you're used to having to engage the switch, but once you're used to it, you'll be golden.

samtuck

sorry to bump this topic but I just wanted to thank Andrew for the tip. my 85 has been running slugish since I got it and recently wouldn't start at all without poping the clutch. finaly got around to working on it today and figured out that the fuel pump did work, just wasn't getting juce. made a little jumper and it did the trick. I've got pics but nowhere to put them online. if anyone wants detal pics of it let me know and I can email them to you.

$100T2

iTrader: (1)

samtuck, get yourself a photobucket account. That's how I do all my pics.

64mgb

iTrader: (1)

That relay is there for a reason...it's a safety thing. Yea, you can get around it, but is it smart to do that? I don't know for sure, but I bet Mazda sells them.

Rich

Rogue_Wulff

Bringing this thread back from the dead. I hope this solves the fuel pump not working problem I have on the 85 GS I drug outta the feild over the weekend.
It will run fine if I pour gas in the carb, but the pump never starts running.
Why isn't this thread in the archives, for easier finding?

nakedfzone

So, do you remove the relay and then do the jumper or just do the jumper?

cdrad51

You remove the relay and then do the jumper.

Pele

iTrader: (28)

It's an easy realy to find, even when you're not in the car. I guided someone through this proceedure with my service manual over the phone... I believe the wire colors were Blue with a White stripe and Black with a Yellow stripe... (There are two of the last one. Either one works.)

There are only four wires in it, evne though it is a 6 spot plug.

aussiesmg

iTrader: (1)

This is very easy, mine went out a week ago, did the mod in 5 minutes, now the jumper can be removed and the car is disabled, extra security measure.

If you reach up directly above the throttle pedal the relay is mounted to what looks like the pedal bracket, just unplug the wires and add the jumper.

Siraniko

iTrader: (13)

I would not run straight without a relay...in other words, no relay, no protection. The eaisest trick is to JUNK the stocker and use fog lights relay. then for kill switch, I used the fog light relay's ground wire.

1BADSP

iTrader: (4)

FYI, the fuel pump and tach run on the same ciurcut with the trailing ignitor,if you replace the ignitor the fuel pump will work,there is no need to bipass the relay.

samtuck

wacky, how exactly does the relay provide protection? I understand how a relay works but I’ve never heard of it being used as any sort of backup or fuse type component

I just unplugged my relay and installed the jumper to the plug, the dead relay is still hanging.

Siraniko

iTrader: (13)

Its simple...I would rather fry the relay than the fuel pump. Mazda didnt install a relay for nothing. For S3, the fuel pump will not turn-on without the engine running which is sucky IMHO. So I re-wired the circuit to have a kill switch and to make it work like prior RX's. Now, when my lawn mower is out of gas...Just unplug the gas line from the carb into a gas can and then turn the key to ON. Who needs a gas station when you have 3 RX's in the garage.

cdrad51

I agree that it sucks that S3 have that mechanism. Yeah Mazda didn't install a relay there for nothing - but I don't think it was to serve as a fuse. AFAIK, it's to prevent flooding if the engine were to stall for whatever reason or the ignition be in the "on" position without the engine running. Installing a switch instead gives you that and more control over when the fuel pump runs, with the advantage that it won't stop running if there is no trailing ignition signal.

Siraniko

iTrader: (13)

Without a relay, you may as well connect the f/p wire directly to a battery.

samtuck

I just lost the blank filler for one of the switches on my dash, might be time to install that switch for the fuel pump. I have been somewhat concirned at times when I have the engine off but can still hear the pump.