1.8 l-jet fires, but dies within seconds, tried searching :-/ Options

[thatguywiththedatsun]

I've been looking for a 914 for a few months now, but life has been in the way. I found one last month that seems to be a good starting point, but I'm having trouble getting it to stay running atm. Seems like it's probably the l-jet system being out of adjustment or leaky, faulty sensors, or some old corroded electrical connectors. The question is; where?

I'm getting a buzzing sound with the key turned to "on" which I initially thought was the seatbelt interlock buzzer everyone seems to be so fond of, but upon closer inspection... it's coming from the injectors..? If i unplug the noisy injector, another one starts buzzing. There's no noise from the fuel pump at this time with the key on. The fuel pump relay, and power supply relay on the board were nowhere to be found when I got the car. I went ahead and bought a few new ones to get it back to stock wiring, but I'm really having trouble deciphering the current flow diagrams. (You guys seems to have a reference system to the pins in every connector, or which specific relay you're referencing. Is there a diagram for this somewhere, or are the labels just buried under the grime in this car?) If i hot wire the double relay (86d, 88d?) to the + battery post, the fuel pump will run, but this doesn't change my "start, rumble rumble, die" situation at all. I have a feeling that there is an area in the wiring that has been altered which, if put back to stock, would rectify the problems I'm having... It's just a matter of finding it and fixing it. Any suggestions?

What I have done:
-compression test: 125,130,90,135 - hoping it will improve pending a valve adjustment?
-tested the coil and wires for spark - checks out fine... nice and strong
-tested fuel pressure - 43psi holding steady for several minutes after the test (p.o. said he'd recently had the fuel pump replaced, but didn't mention why (IMG:style_emoticons/default/dry.gif) )
-renewed all the l-jet vacuum hoses and put hose clamps on every connection
-taken care of a few obvious electrical bugs (missing/rusty relays, broken wires, etc)
-checked the head temp sensor spade connection, but where does the other end of that connection terminate on the relay board?
-checked afm resistance. - With key on, if I move the flap by hand, the fuel pump does run, but there is no 1.5 seconds of priming with the key on, just the annoying injector buzz.

Thanks in advance for the help! I'll be much better off if someone could just explain the 'pin 13/relay 74/etc. references to me.

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[thatguywiththedatsun]

Very useful tests! What I originally thought was the cht seems to be something else. Right behind the distributor, maybe an oil pressure sensor? (IMG:style_emoticons/default/blink.gif) Anyway, resistance from cht (right next to #3 plug wire, right?) to ground is 3.5K ohms, and from cht to pin 13 on ecu connector is a whopping 14.97M ohms. There's something that needs to be addressed. Am I correct in thinking that the cht is bad as well since it reads 3.5kohms to ground? On that note, while the ecu is disconnected, injectors do not buzz with key "on."

With the ecu plugged back in (ignition off, battery three feet away, just to be safe) and all injectors unplugged, they each buzz individually upon being plugged back in one at a time. It seems like only one (random) will buzz if they are all plugged in though. You got a picture handy of those oil seals? There doesn't seem to be anything special under there. There is one o-seal that seems like it would do it's job well enough, but I don't see a flat gasket..?

The pump does run with key "on" if I manually move the flapper, though I can't exactly hear the pump if I try to start it with the key. Even with the fuel pump hot wired to the battery, though, the problem persists. There is a white wire connected to the coil, poorly crimped, but it is there. There is 12v+ on one wire to the injector resistors with key "on," and fwiw, there's no buzzing with the resistor pack unplugged.

Don't really have time to pull the injectors tonight, but that fi harness rebuild may be a good option for me. It seems like half of the wires have cracked insulation from dry heat, or they're fraying at the crimped connectors.

I don't really feel great about making a jumper to the ecu connector boot. Seems like that's a somewhat sensitive area. Next chance I get, I'll get something rigged up and see if that fixes it I suppose.