Rotaryfreak702

Ok my SE keeps blowing its engine fuse.
This all started happening yesterday on the way to work on the freeway and I hit a bump and lost all power and ended up stuck on the side. At first I swore I blew a seal or something but after about an hour of looking everything over I checked the fuses and saw that the engine fuse had blown. I replaced it and all was well.

Now today the same thing happens again. Blown fuse, stuck on side of freeway, and a pack of 20 amp fuses.

Now only this time everytime I put one in it blows once the key is put in the on position. It did about 3 of them.

I'm not entirely sure what components get power from the engine fuse but I know the fuel pump is.

What I would like to know is where I should start looking and if a fuse would blow because of a short prior to the fuse or after.

If it makes any difference I have a walbro 255 installed.

Thanks in advance.

RX-7 Chris

iTrader: (19)

It sounds like you have a wire that is shorting every time you hit a bump. Basically the bump is bouncing the wire into body and shorting the system. I would start by looking at the pump wire that goes through to the bottom of the bin since you replaced the pump. Also look underneath at your pump wiring. Usually wire shorts don't happen unless the wireing has been messed with.

It could also be a shorting relay. I had the choke and check relay short on my SE.

Rotaryfreak702

I will be checking that for sure.

Do you know where that relay may be located.

I'll also check the fuel pump relay as well.

Is there any other areas where there may be a shorting issue?

Keith13b

iTrader: (6)

Choke/Check relay - make sure its not loose or falling apart! Mine was loose and shorting out. Easy fix w/ a punch and happer to crimp the metal housing tight.

Could be something else, but thats easy to check and easy to access/see.

Rotaryfreak702

And where could I find the choke/check relay?

Keith13b

iTrader: (6)

Next to the A/C relay. On the drivers side between the strut and the firewall. Its where a big wireing harness is and a bunch of relays are screwed in together. Its the relay with a metal housing (hence why it shorts out). Pretty easy to find. Up top. Place your hand between the strut and the firewall on the fender. Your fingers will probaly touch the relays!

RX-7 Chris

iTrader: (19)

like keith said it is easy to find.

Rotaryfreak702

So this apparently seems to be a common occurence.

Looking at that right when I get home from work.

Rotaryfreak702

No luck with the choke/check relay.

Any other ideas maybe?

RX-7 Chris

iTrader: (19)

I still think it is probably a short at the fuel pump.

Keith13b

iTrader: (6)

That would be my second guess......however, the C/C relay has caused many o' problem with my friends. Are you using a volt meter to test?

Rotaryfreak702

I checked the fuel pump to see if it was the source of the short but not luck either.

but i didnt check the Choke/Check relay with a multimeter. How do i do that. I'm terrible with electrical.

Keith13b

iTrader: (6)

Look in the FSM to see what connectors do what. The problem lies in a + lead touching the external metal housing causing a short.

Find some help - its very easy to test with a multi-meter. Just need to understand the basics.

74RX4

iTrader: (10)

That fuse protects Black/white wires that supply switched 12v power to a lot of components. All of the soleniods in the rats nest, fuel pump relay (circuit opening relay), control unit, vacuum pressure sensor, choke check relay, alternator, ACV, and both of the main relays.

Might try unplugging the alternator first since it's easy. Main relays are under the hood next to the firewall on the left side near the choke check relay. The Circuit opening relay, control unit and the vacuum pressure sensor are all mounted to the same frame with the ECU covered by a plate under the passenger floor carpet. If the short is inside the component, unplugging it should stop the fuse from blowing.

Rotaryfreak702

So I can just test all of the black/white wires?
And what is all of the black/yellow wires for. Is that just a ground?

74RX4

iTrader: (10)

If the short is in a component, unplugging that component will stop the fuse from blowing. The theory is that the Black/white wires are somehow touching a ground. I would check each component visually and unplug all of them. Put in a good fuse, turn your ignition on and see if the fuse blows. If it does then I would think you have a wiring issue. If it doesn't blow, plug the components in one at a time until you find the one that causes the fuse to blow.

Not sure which Black/yellow wires you are talking about. The starter trigger wire is the only Black/yellow wire I can think of.

Is the Walbro still wired with the stock wiring? Have you downloaded the wiring diagram? Section B2 is the emission control wiring and section A2 is the starting and charging diagram.
http://foxed.ca/foxed/index.php?page=rx7manual

Rotaryfreak702

Yeah the walbro is in stock wiring. But even with it disconnected there is still a short.
I have been using my haynes manual for the wiring diagrams. I'll check out the ones you have link me to.
But fuse still blows with everything disconnected.

Rotaryfreak702

OK ive been at this for hours now. Still cant figure it out.
I used a self powered test light with the battery disconnected and every power wire i touch seems to make the bulb light up which shouldn't happen right.

I dont understand where this could be or how this happened from just a bump on the freeway.

Rotaryfreak702

Could use some help still.
I need my car lol.

RX-7 Chris

iTrader: (19)

I'm not sure why your test light would come one if the battery was disconnected. Have you looked at the wiring to the fuel pump? If there aren't any frayed wires than it is one of the components.