Yeah, I'm embarrassed. I was working on a relatively simple project and accidentally shorted the alternator to a ground on the intake manifold. See picture. I was a bit surprised that the cable on the alternator was hot. Anyway, now the car will crank, but not start. I'm not getting any fuel smell so my ignorant guess is that I fried the fuel pump or a fuse?

I've been going over the wiring diagram but so far have not found it. Does the fuel pump have a fuse, and if so where is it? What else might I have shorted out and any suggestions on where to look?

I've only had my FD 3 weeks and I've already broken it.

I shorted it out between the two arrow points.

 

The fuel pump has a relay located in the front most fuse box in the engine bay. It's right next to the hood latch.

 

Get a tester and find the fuse you blew.

 

Open the diagnostic box next to the batter(small square shaped box), take a piece of wire with the bare wire exposed on each end, and conncet the F/P to the GND inside the diagnostic box. Once connected turn the key to the on position and you should hear the fuel pump come on. You can also put your hand on the fuel feed line(Lower left when standing next to the driverside front wheel) and you should be able to feel the pressure if the pump is working.

Also check the EGI fuse which is in the rectangle shaped fues box attached to the positive side of the battery. I have blown that fuse before when a car had an electrical problem.

David

 

Yeah, the problem is finding all the fuses. Also, without the fuse puller, what is the easiest way to remove them?

BTW, I just checked and there are some more electrical problems than just not starting.
Headlights and flip motor work but Tail lights don't.
Dash lights are out.
Door chime is out.
No sound when the key gets turned just prior to cranking (I'm not sure what happens, but I've always thought it was the fuel pump that makes a bit of a noise as the key is turned to the on position? Now there is nothing but a very faint click.)
Turn signals are out.

 

Probly one of the main fuses on the drivers side iner fender, you might be able to see if its blowen. The fuses pull out pretty easy.

 

Pretty much all of the fuses are in black boxes in three locations: (1) in front of the intake, (2) next to the battery, and (3) in the driver footwell.

 

I checked them all except the Main 120A fuse. I finally decided to check it (although as near as I can tell if it was out not much would work). Unfortunately, I figured it just pulled out like all the other fuses. Now I don't know if it was really good or not, as I ripped it apart. Funny, I didn't know about having to under the Main fuse retaining bolt. Anyway, I now need to get another 120A main fuse. Any idea if a local Mazda dealers might carry that?

 

I've never had to mess with the main fuse, but have you checked with the local AUTOZONE etc?
There used to be a red plastic shroud/boot over that alternator terminal. As soon as you get things sorted out, you might want to get it covered again...electrical tape, self-fusing tape, something.

 

this sounds pretty much EXACT to what happened to me. i also grounded the AXACT same alternator wire. and i was having the exact same symptoms (the lights and stuff)

turned out i blew the main fuse (fuse box by the battery) and yes, it did have the two bolts on both sides of the box that hold the fuse in place.

so im just posting this to let you know that im pretty confident that this was causing the problems. (no need to worry if the fuse was really blown or still good.....it was probably blown)

 

Yeah, I was thinking the same thing. The tape would need to be able to take some pretty high heat. I suppose I can ask at an autoparts store and see what they might recommend.

 

auto part stores do not carry a big enough fuse. and I looked into why the alternator wire has power on it but i cant figure it out cuz it supplies power if anyone knows please share. but yeah I dropped my alternator once and it blew my big fuse luckly I had a spare harness lying around. Have you figured out yet that that fuse bolts in?

 

I can't offer any help with troubleshooting, but I can offer some advice.

Before you start working with the main fuse and the bolts that hold it down, disconnect the ground (negative) from the battery. That way, when you're working with the open end or socket and hit the chassis, you won't repeat your mistake.

There are a few heavy gauge wire spots on the car that are always hot. The positive on the batter, the alternator connection (you already found that one), and the starter solenoid are the main ones that comes to mind.

 

The local MENARDS hardware store carries this brand, but there are other sources, like McMaster Carr. If you've never worked with it...there isn't any adhesive, just a strip of silicone layered in mylar. Cut to length, peal off the mylar and wrap it around. It fuses to itself. Stands up to about 500 F. and insulates to about 4 billion volts. Good stuff.

 

I sure hope your right and it makes me feel better knowing that my hunch about the main fuse may be right. It looked good, but after pouring through the entire wiring diagram, it seemed as if a bad main fuse was the only thing that could give me the symptoms I'm getting. It was also nice to know that I'm not the only person to have done something so, err... less than intelligent?

Just so I don't screw things up more than I have already, are these the bolts that I have to remove to get out the rest of the fuse (yeah it came out in pieces, you can see one of the blades still there in the picture) and put in the new one?

Looking at the Main Fuse box from the left


From the right

 

I was also wondering why that wire to the alternator was hot even when the key is off. Doesn't make sense to me.

I figured out about the bolts after I tried ripping the main fuse out with pliers. See the pictures above.

 

I'm going to be much more careful around the engine bay from now on. I've already disconnected the ground from the batter (I do learn, albeit slowly and painfully), and will disconnect the positive from the battery before I try loosening the bolts. Am I pointing at the correct ones in the pictures?

OUCH! I just found out how much that fuse is going to cost me. A bit over $90 with tax for next day service at my local dealer. I definitely don't want to blow this puppy again.

 

I'll look for it. I'm noticing a lot of similar problems under the hood where the wiring should be recovered.

 

The alternater wire is tied into the main power harness becouse it charges the battery and works best not interupted by a switch. Plus its cheaper to build!

 

get yourself a DMM(digital multimeter) or the test light tool from snap-on, turn your key on to pos 2 and check every fuse, if there is power at one side should be at the other side, if there is ground at one side there should be at the other side so on and so forth

 

also check the egi relay its yellow when i did this it was also blown.
another 75 bucks.

 

Any idea where to find out how to check the EGI relay? I'm assuming it must be in the shop manual somewhere....

 

you have to open it to check it.

 

You should be able to get another 120v fuse from someone parting out a car.

I too learned (thankfully not by breaking) that the main fuse has a retaining bolt.

Dave

 

OK.... Not wanting to spend $90 on a fuse, I did some more checking. It turns out that there is another fuse that fits most Mazdas from '91 on. It is also a 120A fuse, but it isn't specifically for the RX7. It only costs $7.00. I bought two from another Mazda dealer who had them in stock and it only cost me a couple gallons of gas and 40 minutes of time.

I had a patient cancel just before lunch. I took off for the dealer, picked up the fuses, went home, installed the fuse, put all the parts back together that I had taken apart, connected the battery and she started up first crank.

Thanks to everyone for the great help and thoughtful advice. I really appreciate it.

Now I'm back to trying to remove that Greddy Oil Filter relocation kit without breaking anything this time.