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ECU BLOWN? Cranks but no power?


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Hey guys, 

I have an 84 GL Wagon 4WD here that has been giving me one hell of a run for my money. I pulled the motor last summer and everything went fine. I only replaced intake manifold gaskets, exhaust header gaskets, head gaskets, and oil pan gaskets, no internals. Got it back in and everything went fine and it sat all winter in my driveway. This summer, I got in it, it fired up, idling kind of rough and drove it about 300 yards down the road and back up. Everything was fine. Upon trying to start it days later I was getting spitting out of the carb. I went full bore and replaced the ignition switch, distributor cap, fuel pump, entire carbeurator to the weber dgv 32/36, tuned the carbeurator to the specifications, replaced the alternator and starter. I am getting power to the starter relays, the starter, the battery has 12v, and the ignition coil. I was getting power to the dash when I turned the switch to the ACC position and the fuel pump would prime. But I turned it off and back once more and all the dash lights shorted out. Now I only hear a click from the starter relay when I turn to the ACC position. The car still cranks over but I have no power to the fuel pump as the under hood fuel filter emptied. 

My thoughts are the ignition switch could've shorted somehow and gone bad... OR it may be a bad ECU

I noticed that in the ACC key position the ECU has a red light that flashed every couple seconds. 

Any input would be greatly appreciated. The first 3 weeks were tolerable rolling around on the gravel and smashing my knuckles but this is just getting down right frustrating. 

 

Josh

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On 7/11/2020 at 10:13 PM, GeneralDisorder said:

Check the fusible links and all the fuses. 

GD

checked all fusible links I know of. The ones under the dash. No change. Replaced the ignition switch as well. Nothing. ACC key position provides three little clicks from the starter relay then nothing...

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4 hours ago, JSIMONIS97 said:

checked all fusible links I know of. The ones under the dash. No change. Replaced the ignition switch as well. Nothing. ACC key position provides three little clicks from the starter relay then nothing...

Look at the wiring diagrams and find out what is common to all the things not working.  From what you've described, it does sound like a fusible link failure.

How did you check the fusible links ?

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I recently had a similar issue. Found a few exposed wires (bl/y, fuse 13) one at the ecm plug, one behind the stereo, and a few in the bay. Make sure to check your ig coil and fuel pump relays. 
 

Also, factory wiring has several splits with a copper band, I found several that needed rerouted or I used liquid electrical tape to stop short to ground. 

Edited by glsubby
Grammar
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All was running nice after rebuild I see

On new season start up rough idle, you drove it then said all was fine....so the 300 yard drive resolved idle issue? As you then said "fine " again?

Spitting out the carb, and rough idle can be a valve sticking in the guide, due to at least one reason , stale old fuels, chemicals falling out of mix and concentrating on valve guides

More than one issue and the above may be a red herring to your electrical problem but good you shared history :)

Because it cranks, what about share compression test results?

Some of us older guys would love a roll in the gravel with a 36 year old troublemaker

What if you get back to basics and disconnect fuel pump, make your own temporary , switchable power supply to pump and ignition coil

You only need to pump to fill fuel bowl prior to starting

12v hot wire to coil + terminal with other wires to this terminal off and insulated away somewhere

Dash gauge set been out? There is a Blue wire with black trace I think bullet connection off short wires at rear of gauges, disconnected has caused me grief before.

test the light bulbs in back of dash cluster in case something popped them?

 

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I still don’t get how it’s an EA81, originally with a stock hitachi carb and it has an ECU! 

Why has it got an ECU?? Is this a Californian emissions thing?? 

Ill leave you to it and hope that a) you get this sorted and b) someone can enlighten me. 

Cheers 

Bennie

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I think we had O2 sensor controlled carbies here at some stage Bennie, or I have seen it on "grey" imports ( looked away real fast). I think the ecu is very basic and controls the enrichment ports of a carby

Edited by Step-a-toe
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23 minutes ago, Step-a-toe said:

I think we had O2 sensor controlled carbies here at some stage Bennie, or I have seen it on Greg imports ( looked away real fast). I think the ecu is very basic and controls the enrichment ports of a carby

To be sick I bet! 

I’ve only seen SPFI and heard that referred to as carby controlled ECU. Who knows if that’s correct... 

Cheers 

Bennie

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18 hours ago, Step-a-toe said:

All was running nice after rebuild I see

On new season start up rough idle, you drove it then said all was fine....so the 300 yard drive resolved idle issue? As you then said "fine " again?

Spitting out the carb, and rough idle can be a valve sticking in the guide, due to at least one reason , stale old fuels, chemicals falling out of mix and concentrating on valve guides

More than one issue and the above may be a red herring to your electrical problem but good you shared history :)

Because it cranks, what about share compression test results?

Some of us older guys would love a roll in the gravel with a 36 year old troublemaker

What if you get back to basics and disconnect fuel pump, make your own temporary , switchable power supply to pump and ignition coil

You only need to pump to fill fuel bowl prior to starting

12v hot wire to coil + terminal with other wires to this terminal off and insulated away somewhere

Dash gauge set been out? There is a Blue wire with black trace I think bullet connection off short wires at rear of gauges, disconnected has caused me grief before.

test the light bulbs in back of dash cluster in case something popped them?

 

i will take this all into consideration and start testing the above mentioned. Im only 23 and this is my first teardown and rebuild. Much to be learned 

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