Last night I tried to start my 914 to move it out of the garage...and it didn't start. When I turned the key, the auxiliary fan came on because the lever was pulled back. I turned off the fan, then proceeded to start the engine and it just cranked. I turned off the key, then turned it to the on position. This was when I noticed the fuel pump didn't come on. Why? During my check I discovered the rear fuse of the two on the relay board in the engine compartment was blown. A little research told me that this fuse is for the fuel pump and aux. fan.

So, I disconnected the fuel pump, put in a new fuse and it blew when I turned the key. Another new fuse, reconnected the fuel pump, disconnected the aux. fan, turned the key and the fuse blew again. It's not the fan. What is causing this? I drove the car in there less than two weeks ago!!

It's strange that the aux. fan came on the first time I turned the key. Now it won't work with the fuse blown.

Somebody please help me. I have to move everything out of this rented garage tomorrow. This includes my 914. I'd rather not have to tow it if that can be avoided.

fix the short ...


it's probably the aux. fan and/or switch.

disconnect the fan first, look for obvious signs, like cracked/exposed wires.

also, the connector on the switch is dangerously close to ground and can easily shorten out. unbolt the switch and test with switch removed.

Andy

It's the wire that powers the AAR. It's shorting out.

OK. I'll take the switch out. I figured disconnecting the fan wiring back at the fan would take it out of the equation, but maybe that's not enough.

Thanks.

forgot about that one. that's on the same circuit as well ...
Andy

Cool. Where the heck is it?

red wire, going to the AAR ...

post a pic of your engine bay!
Andy

White wire that comes out near the distributor. It's in the same bundle as the tach wire (black/purple), coil wire (black), and oil pressure switch wire (green/red).

huh? on my '70 1.7L, the wire was red, not white ...
Andy

This is the only pic I have right now, and it sounds like it's from the wrong side. I'll head over to the garage now and check out the wires. Which is the AAR? That would help me, regardless of the wire color.Click to view attachment

Sorry, forgot the image.

Andy, it might be red on the early cars.

The AAR is the canister that mounts right near the air box and has two largish air hoses, one coming from the filter housing the other going to the plenum.

Ok, thanks. I'm off to see if I can fix it. I'll report back later.

You could try removing both relays for the fan and the fuel pump and see if the fuse still blows. If it does, it's probably not either of those. If the fuse doesn't blow, replace one at a time to isolate the issue.

Disconnect the fan and fuel pump and check.

I doubt it's the fan switch by the shifter since it grounds the negative side of the relay thus even if shorted to ground, will not cause a short.

Spoke

Its a red wire coming out of the AAR (all years), connecting to a white wire on the ignition harness with a long single pole box housing.

What is an AAR? I've seen AAR several times. All American Rejects, that is. They rock

Spoke

Auxiliary Air Valve, basically it's a controlled air leak to keep the idle high while the motor is cold.

Jeff, thanks for setting us straight.

Wellll............

Common gremlin, I even made a schematic

This is exactly what I found. The wire didn't appear to be grounding anywhere. When I unscrewed the AAR from it's base, the fuse did not blow, the fuel pump worked, and the aux. fan worked. Reattach the AAR to it's base and the fuse blows. Is the AAR itself bad, grounding internally?

I just left the wire disconnected and drove it home. Idle stayed high, but it ran fine.

yupp, the AAR grounds through the engine case. if the fuse blows, the AAR is broken ...
Andy

Thanks, gents. So...what do I do now? Replace it? Eliminate it? Jim Kelly, who lives near me, said he may have one. Looks like they're NLA, so used is the only way to go.

Just to make sure, in what condition was the plug to the AAR? The most common problem I have found with those is not an internal short, but rather the plug being uninsulated allowing it to ground against the case, often intermittently. If the plug has bare metal showing try insulating that first.

That's a good question, and I paid attention to that when I was checking everything out. The wire coming out had a rubber sleeve that slid all the way down, protecting it from grounding on the mount. Also, just to be sure, I attached only the left hand bolt, leaving the AAR askew on it's mount. I figured keeping that wire away from the mount while still attaching the AAR would rule out the possibility of the wire touching the mount.

Is this what you're talking about, or am I still missing something?

Nope, ya got it. Good thinking

If possible, measure the resistance of the AAR with an ohmmeter with connector removed. If near zero ohms, then you've found the short. If even a few ohms, it might be ok. Consider 3 ohms with 12V is only 4amps so it must be near a dead short.

OK, I'll check that out. Won't be until this weekend though. I just moved out of my rented garage, so the 914 is outdoors now. And it's dark when I get home. It'll have a new home soon, though.

yo dog - got this one set aside for you

Thanks, Jim. Again, you've helped a brother out when he needed it. What's your favorite restaurant?