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, 02:14 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 |
The injector buzzing sound is very intriguing to me.
My first initial thought was your dual relay. When you turn the ignition switch to the "on" position, the fuel pump should NOT turn on, this is normal. Your fuel pump only activates with you turning the ignition key to the "start" position. At this position, the fuel pump receives power thru the dual relay. When you release the key from the start position, the air flow meter takes over and keeps the dual relay engaged. Since you applied power to pin 88d on the dual relay, you essentially bypassed the dual relay. This test confirmed that your engine is not dieing from lack of fuel. With a Ljet setup, your relay board isn't all that necessary for it to run. The 2 fuses on that board are not required, along with any relays plugged into it. All the wires needed for a running state, runs thru the relay board. So at this point, I wouldn't worry about the relay board. Your CHT sensor is not wired directly to the relay board. This wire should be part of the fuel injection wiring harness, that leads to the ECU. This needs to be connected for your car to run. Capn Krusty has supplied me and many others with a manual for trouble shooting Ljets. I can email you a copy if you wish. If you were to unplug the ECU connector and ohm out pin 13 to engine ground, you should have around 2k ohm of resistance (depending on ambient temperatures). Your fuel pressure is way high. Do you have a fuel pressure regulator installed on the fuel loop? Also, your compression test is somewhat concerning. You may want to double check the valve lash on the offending cylinder. The proper way to test compression is with the engine warm. So after we figure out what is wrong with the staying running problem, you may want to re-check the compressions. Back to the buzzing injectors. Again, really odd problem. If you unplug the ECU connector, does this buzzing go away? |
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