1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

no power to ecu, coils

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Old Dec 27, 2009 | 11:44 PM
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no power to ecu, coils

So, my -SE just randomly died. with the key on, I get brake and coolant dummy lights, no oil p. or alt. It cranks just fine. However, it doesn't get spark, and the injectors don't fire. Im getting fuel to the rail. Im getting power to and through all the fusibles. No blown fuses. Not getting power to either of the ECU connectors. Can't find any bad grounds. What am I missing?
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Old Dec 27, 2009 | 11:48 PM
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Check your fuseable links, they can break internally and not destroy the fabric casing. Happened to me.
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Old Dec 28, 2009 | 12:09 AM
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that was my first thought. However, Im getting power through them. So theyre all good.
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Old Dec 28, 2009 | 12:13 AM
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How are you checking the fusible links? If you connect a test meter from terminal to terminal, all that does is complete the circuit and bypasses the link Link needs to be unplugged and tested from the unplugged end to the terminal. If those are good, prop open the flap in the MAF and see if that makes a difference.

Are you getting a tach signal during cranking? If not there may be a bad wire or the trailing ignitor is toast.
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Old Dec 28, 2009 | 12:28 AM
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Checking them to ground, both sides. I get 12v everywhere. Does the trailing ignitor give signal to the eco to fire fuel and spark? Ill try the flapper door.

And still for some reason, no power to + side of coil with key on. That would tell me ignition relay, only it cranks.

the trailing ignitor probably is bad. About 2 weeks after I bought it, after Id been driving it the whole time, I noticed that the T ignitor was unplugged, and had been the whole time. WHen I plugged it back in, it made no difference in how the car ran or idled.
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Old Dec 28, 2009 | 12:49 AM
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The trailing does very little for power, 2-3% at most. It's main purpose is to clean up emissions. The tach is fed from the trailing coil. If the trailing ignitor goes out, the engine won't start, it will crank though. Maybe the PO changed some of the wiring around. Time to download the wiring manual and start checking.
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Old Dec 28, 2009 | 01:01 AM
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Sigh... I know. I'm really not looking forward to it. Goddammit, why can't someone just know exactly what is wrong and tell me how to fix it?! You're all useless!!
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Old Dec 28, 2009 | 03:53 AM
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But that would take all the fun out of it and in the end, what would you learn about your car?
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Old Sep 25, 2010 | 05:47 PM
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A little update.

Swapped out the ECU, ignition switch, both main relays, and the ignitors. Still, no power to the coils or ecu. So I broke out the wiring diagram, and started checking everything. The main relays control pretty much everything in the ECU power department. The relays are getting power to them, have ground. They get they're signal directly from the ignition switch., through a 20A fuse inside. Heres where it gets wierd.

With the ignition switch OFF, I get continuity between the ig. switch, and the relays, but its about 30 ohms. With the switch in the ON position, no continuity. If I jumper the "switch" terminal on the relay to the battery, BAM, power everywhere. So the relay isn't getting told to close. Could it be TWO bad ignition switches? The wire in question is the BW coming off the back of the switch. Goes from there to the fuse block, from fuse block to relays.

Im hoping someone could take a look at the diagram for me, double check what Im looking at. Feels like Im missing something stupid here.

Thanks
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Old Sep 25, 2010 | 06:55 PM
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Sound like a bad wire to me. Is there any way you can expose the wire a both ends and put a jumper between them? What page in FSM wiring diagram are you using? I'll take a look at it also. I know my Navy Electronics Technician training would come in handy. Of course it's been 20 years since I got out.
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Old Sep 25, 2010 | 07:47 PM
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Its in section B-2, "13-B engine EGI and Emissions control". The copy I have doesnt have page numbers.
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Old Jan 4, 2011 | 04:48 PM
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make any progress on this?
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