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Dave at Pelican Parts Dave at Pelican Parts is online now
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Join Date: Dec 1969
Location: Silly-Con Valley
Posts: 14,946
Garage
Amazing, this "troubleshooting" stuff actually works!

I stopped by my friend's house earlier today. This is the friend who has been storing my 914 for me.

The battery was flat, as we had expected. We used booster cables from his Subaru to help that out. It cranked, but did not start.

I checked the fuel tank contents. Had plenty of gas, and it even smelled like fuel--not varnish. I listened for the fuel pump. Hmm, no buzz! And my pressure gauge read zero. So I used a jumper wire on the fuel pump relay. I got a little bit of noise from the pump, but not the usual sound. I pulled the wire and tried again. Hey, the noise is a little louder. Tried it again, the noise is louder. Three or four more of those, the pump was buzzing normally and the fuel pressure regulator squeaked at me like it does when it works. 20+ PSI on the pressure gauge! Hey, the pump was just stuck!

Tried to start again. Nothing.

Pulled the center coil wire and held it near a ground. It got sparks when the starter was cranked.

The starter sounded like it was encountering resistance, so I figured I probably had compression.

No fuel smell at the tailpipe. But the pump was running. Fuel pressure stays at 20 PSI, even when I pump the throttle. Were the injectors stuck? No jars handy to test the injectors--too bad.

What could cause no injector activity? It could be electrical. But the MPS is plugged in firmly. So are the trigger points. Yes, and the four-pin plug on the relay board is as well.

I check the fuses on the relay board. They're both OK, even when I take them out and look them over. Grotty and ugly, but not popped.

Perhaps one of the relays went south? The cover of the heater blower relay pulls off so I can push on the switch part inside. That makes a nice testing part. OK, I know that I can use the jumper wire to make the pump run. What about the FI power relay?

Swap the blower relay in. Push the switch to close the relay. Hey, there's a click elsewhere when I do that? Let's see if there's any activity when I force power to go to the FI. Can you crank the starter while I hold this?

AHA! It almost started. So I leave that relay in place, clean up one or two things, and try again. It starts and immediately dies, but the next time it catches.

Success! My 914 does indeed run. I drive it home, only to discover that there is probably something blocking the oil cooler (the oil temps got very hot!) and one of the brakes is stuck (brake smell and the fluid wound up boiling).

Still, it's nice to have the car running again. And I guess there is something to be said for this methodical troubleshooting stuff, huh?

--DD
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Old 04-29-2012, 04:12 PM
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