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Discussion Starter #21 (Edited)
My other hondas are '98, obd 2.
I will look at injectors, don't know if they have been swapped. Will check resistance on injectors.
Also, I see from wiring diagram the injectors get power from MR#3, through 2 connectors, and nothing else. Should I be looking for continuity from MR#3 to injectors? Thanks, Inky
 

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Sloppy Jalopy
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Any way to check the ECU's you've tried in another car to see if you're fking them or if your car has other issues?

Any chance OBD0 injectors have been swapped on without the resistor box and it's burning through ECU's? (Check resistance across the injectors)
hmm good point..
My other hondas are '98, obd 2.
I will look at injectors, don't know if they have been swapped. Will check resistance on injectors.
Also, I see from wiring diagram the injectors get power from MR#3, through 2 connectors, and nothing else. Should I be looking for continuity from MR#3 to injectors? Thanks, Inky
you can see if has battery voltage on one injector wire with key on.
 

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Sloppy Jalopy
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if you still have power on ecu a25,
follow the yel/blk to junction c128 ,the caped off plug with a bunch of yel/blk wires going to it..

have you noticed if the wiring has been worked over on this car?
 

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Also, I see from wiring diagram the injectors get power from MR#3, through 2 connectors, and nothing else. Should I be looking for continuity from MR#3 to injectors? Thanks, Inky
Yeah there should be continuity along the YEL/BLK wire between the ECU (Both A25 & B1), the main relay (MR#3) and the injectors (YEL/BLK wire). There should also be voltage with the ignition switched on.

If you don't have power, start checking fuses (underhood and under dash)
 

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Discussion Starter #26
Many Thanks to EFBO55, and robgoof for all the help.
I repaired a short between the MR#3 and the injectors.
The car starts and runs, but I have to jump MR#8 to ground, if I remove jumper fuel pump shuts off and car stops running. Should I put a ground to MR#8 and leave it on, or should I put a switch between MR#8 and ground so it will also act as a kill switch? Inky
 

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good to see some progress ,
so it was a shorted wire going to the junction?
putting a switch or a ground on mr pin 8 would be a safety hazard.

have you opened the ecu to look for obvious damage?
 

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Discussion Starter #28 (Edited)
There were 2 wires at MR#3, 1 had 12v the other did not, I cut the one that didn't have 12v and connected it to the one with 12v.
The ecu has a reman sticker from 2018, previous owner bought it, it had a major burn out from the look of it, the burn residue on the case is 1.5 inch circle. It's too messy in there to tell if there is new damage or just remnants of the previous burn out.
When I get done putting wires back in place, i may try my other ecu ( 5 speed ) just to see what it does.
 

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BATSLOMAN GIVES NO FUCKS.
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replace it
 

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Discussion Starter #30
I plugged in the 5 speed ecu in, did not start, jumped MR#8 to ground, car started and ran p, disconnected jump wire and car continued to run, shut it off and restarted and ran without any jumper. I'm going to stop for now, its 93 under the sun, go home and cool off, will see what happens tomorrow.
Thanks, all. Inky
 

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Discussion Starter #31
&%*#$%, *@#&$^
Turned the key to start, no chk engine light for 2 seconds. No fuel pump turn on, jumped #8 to start Fuel pump, still crank no start. ?????????, Inky
 

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What's the deal with the ECU's again? Were they known working?

If they were, you need to find another car to test them in now you've had them in your car. If you're toasting ECU's then you've got bigger issues.

do you have the workshop manual to identify all your grounds and check they're tight and clean?

Checked all your fuses? Fuel pump fuse is on the ECU circuit.
 

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since you spliced the wiring did you ever look into why the yel/blk wire to the junction had no power,broken burnt?


like efb055 said you got to try the ecu on another car..to make sure it works or doesn't..
 

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Discussion Starter #35
What's the deal with the ECU's again? Were they known working?
If they were, you need to find another car to test them in now you've had them in your car. If you're toasting ECU's then you've got bigger issues.
like efb055 said you got to try the ecu on another car..to make sure it works or doesn't..
One came with the car (Reman2018 A51), crank no start. Other was a used purchase, (A01). After diag tests, manual says " replace with known ecu and retest" So, I purchased second ecu, plugged in and the car stared and ran, next day, crank no start, just like two days ago, same thing. Both ecu's have started and run this car at different times, so I don't think I'm Frying them. However, I don't know anyone with a car that I can see if ecu work's in their car.
do you have the workshop manual to identify all your grounds and check they're tight and clean?
I do..............every ground on the whole car?
Checked all your fuses?
Before i start, I check battery voltage, fuses - 3 - 18 - 24 - 31 - 32

 

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Discussion Starter #38 (Edited)
You are correct, Sir. I do plan to go out and work on it tomorrow.
I did buy a digital circuit scanner diagnostic tool, if I learn how to use it. The instructions say "do not use on any component or circuits of the ignition system"
IMG_20200720_191526259.jpg
 
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