Guest Anonymous Posted October 9, 2001 Share Posted October 9, 2001 I have put an 82zx engine, efi wiring harness, afm,fi,distributer, and sevral relays in my 77z. Now after tracing wires through the 82 I get it to run for about a second, any Ideas??? the other question is how is the light on the ecu suppose to act??? I get green in the on position then when I turn it over it goes out and stay out does sound right to me but I havent had a ecu with a light befor...Please help if you can. Thanks Guys Dave Quote Link to comment Share on other sites More sharing options...
blueovalz Posted October 9, 2001 Share Posted October 9, 2001 I had the engine ignition circuit tied to the starter circuit one time that caused this. The engine would try to run when I would start it, but as soon as I released the key, it would die. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 9, 2001 Share Posted October 9, 2001 thanks for the input but it doesnt seem to matter. If I keep the key on or off it still dies. Just scratching my head and going huh. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted October 9, 2001 Share Posted October 9, 2001 Hey daveyz i had the same problem and it turned out to be the efi relay it wasn't letting the injectors work.Check to see if it's getting power and acually switching.I changed mine and it fixed my problem.It could also be a bad wire or an unhooked one on the efi harness.It sounds like the fuel pump is working.The reason it starts and then shuts down is cuz the cold start injector is working.Try that and see if it helps Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted October 27, 2001 Share Posted October 27, 2001 Daveyz, I agree that you are probably experiencing a relay problem of some sort. I had problems w/my fuel system & it turned out being a fuel pump relay. In my quest for determing the problem I discovered that my z (1978 bone stock/per the factory manual) had 3 fuel injection relays. . Fuel Pump Relay . Fuel Injection Harness Relay . Fuel Pump Controller Relay One Fuel Pump Relay engages the fuel pump when the ignition switch is engaged, the ECM does a quick check of all FI components in the harness & if everythings good to go then it allows the engine to keep running. Now, if the ecm detects a defect in the harness then the ECM shuts the Fuel Pump Controller Relay down & your engine dies! Or you may just have a defective Fuel Pump Controller Relay. My problem was a Defective Fuel Pump Relay. I bought a new one from AutoZone, special ordered & took a few days. Once I installed it & the car started immediately. If you have a factory manual it gives in detail how to check your relays...which prongs to power & which prongs to ground during testing. Check your manuals. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 27, 2001 Share Posted October 27, 2001 Sometimes it is hard to see the forest for the trees! Do you have access to a fuel pressure gauge? If you do, install it between the fuel filter and the engine. Pull the alternator field wire connection out and leave it out. Remove the oil pressure "sender" connector also. Now disable the starter by removing the male spade connection at the solenoid. While watching the pressure gauge, crank the engine. The bypass circuitry of the relays should fire the pump in the cranking position of the ignition switch. If it does not, take a 12V test light and check the cold start injector by removing the EFI clip to it. Probe both connections one at a time while cranking. One side should be hot during the cranking. The cold start and the fuel pump get their bypass signal from the same delivery point. If you have power at the cold start, check for power at the pupm in the same way. (under the padding on the passenger side behind the seat is a quick connection point for the fuel pump wiring and a good place to make this test.) All these tests will tell you is that the pump either works or it doesn't for what ever reason. If all tests are good for function of the pump on bypass, note the fuel pressure reading. Release the key, the pump pressure should drop slightly by hold solidly. If it does not, look to the non-return valve in the fuel pump for leaks. (Sometimes an errant fuel pressure reg will do the same thing) Hook the starter back up and crank the engine, the engine should start if the thermotime switch has had enough time to cool off. The duty cycle of the cold start is 1 to 3 seconds, then it takes as long as 15 seconds for the bi-metal strip inside the T-Time switch to REGROUND the cold start valve. So 3 on 15 off. Don't be impatient, this is normal cycling. If the motor dies again, be sure to look at the fuel pressure when it does. If fuel pressure holds, then you are looking at a control side (brain) or a input side (secondary ignition) signal function loss. It wouldn't hurt to tape down the trigger of your timing light and attach it to the COIL wire during all tests. Many times a loss of ignition will be overlooked. (See first sentence in this post) If you have constant fuel pressure, then you can manually inject fuel into the engine by hot wiring the cold start valve to a remote starter switch. Remove the cold start connector. Connect battery positive to one end of the remote and the other end to any terminal of the cold start. Ground the remaining terminal of the cold start. An old EFI clip works nicely for this test. Have someone crank up the motor and just as it starts to die, "bump" the cold start valve with the remote switch. Judicious application of throttle opening with one hand and "bumping" of the cold start will allow you to keep the engine running long enough to observe running fuel pressures. Remember that in order for these systems to work, they must have a pure DC feed. Any AC flood caused by defective alternator diodes will tell the fuel pump relay to shut down, as well as really mess with the ECU's mind. The three power supplies which must function to go from crank to run are these. `1. Cranking signal from the ignition 2. Direct power from the battery at the Fusible links or at the positive terminal. 3. Run power in the ignition position. All it takes is for one of these to be missing an you will experience either a no start or a no run after start. Get back to basics. The timing light will help to determine the "run" power generation "coming" from the ignition switch.(The ignition relay actually does the work) If all else fails, remove the distributor and ground the coil wire to the chassis. Do not disconnect the dizzy primary wires. With either a noid light for checking injector pulse or an old points/condensor dwell meter hooked to any one injector harness clip, spin by hand the dizzy. (ignition in the run position). The noid light shoud flash, or the dwell meter needle should bounce with each ground cycle of the injector by the ECU. Failure to see any pulse at the injector clips is either major loss of grounding for the entire system, loss of input siganl from the dizzy, or simply a bad ECU. If all of this doesn't point you towards some new answers, E-mail me directly at Smokyyaro@AOL.com and I will give it another try. Kim Quote Link to comment Share on other sites More sharing options...
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