1.8 l-jet fires, but dies within seconds, tried searching :-/ |
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1.8 l-jet fires, but dies within seconds, tried searching :-/ |
thatguywiththedatsun |
Mar 21 2014, 01:36 PM
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#1
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Newbie Group: Members Posts: 21 Joined: 21-March 14 From: Memphis, TN Member No.: 17,144 Region Association: None |
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. (IMG:http://www.914world.com/bbs2/uploads_offsite/lh5.googleusercontent.com-17144-1395430598.1.JPG) (IMG:http://www.914world.com/bbs2/uploads_offsite/lh5.googleusercontent.com-17144-1395430599.2.JPG) (IMG:http://www.914world.com/bbs2/uploads_offsite/lh3.googleusercontent.com-17144-1395430600.3.JPG) (IMG:http://www.914world.com/bbs2/uploads_offsite/lh3.googleusercontent.com-17144-1395430600.4.JPG) |
timothy_nd28 |
Mar 21 2014, 09:45 PM
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#2
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Advanced Member Group: Members Posts: 2,299 Joined: 25-September 07 From: IN Member No.: 8,154 Region Association: Upper MidWest |
Yep, pin 13 on the ECU plug to engine ground. The CHT is located next to the number 3 cylinder and depending what temperature your engine is, 3.5k ohms could be within spec. Go ahead and double check this at the ECU plug, it should read the same as you measuring right at the CHT to ground. If not, then Jeff Bowlsby may be in order for your harness
The oil pressure switch is located by the distributor, but this isn't required to be hooked up for the engine to be running right now. Okay, next test. Remove all wires on the negative terminal on the ignition coil. We need to protect your points or pertronix module while doing these next tests. After this is done, remove the ECU plug and turn the ignition switch to the "on" position. With the meter set to DC volts, put one meter lead on the negative battery post and the other meter lead needs to probe pins 14,15,32 and 33. You should see 12 volts on every pin. After this, turn the ignition switch to the off position. Measure pin 10 on the ECU connector, you should read 0 volts. |
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