Have you unplugged the ECU and plugged it back in
[SOLVED] No power, enters limp mode on acceleration
- Thread starter chris' speed 3
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Enki
Motorhead
This could be a good thing to reset it all. I have heard of early on when the speeds first came out people had issues with it going into limp mode which I think is basically like what you're describing
chris' speed 3
Greenie Member
I did unplug it since the problem started i think i did it twice but i can ask them if they've done that. i know they've reset it from the scanner but thats not the same as physically unplugging it I would assume
I was reading up on ecu failures, im thinking if it is that maybe its the ignition circuit that is failing to hold the right amount of power. I would assume cylinders 2 and 3 are related when it comes to ignition
Edit: 18 pages on this thread
hope its figured out soon
There have been people with weird shit where this has fixed it. Some reported that the connector didn't seem fully seated at first
chris' speed 3
Greenie Member
Finally reporting back with what the problem is! So on the waveforms the injectors on cylinder 2 and 3, the voltage drops and doesn't hold at 60v which is why it goes lean and my fuel trims are crazy high. Now they tested the wires leading from the injectors into the ECU and the resistance is all in spec.
Inside of the ecu cylinder 2 and 3 are connected I don't remember exactly what he said but they're connected which leaves the ecu as the only culprit. So new ecu or is there a way to fix the current one? or is it something else possibly causing the voltage drop
thanks guys
Inside of the ecu cylinder 2 and 3 are connected I don't remember exactly what he said but they're connected which leaves the ecu as the only culprit. So new ecu or is there a way to fix the current one? or is it something else possibly causing the voltage drop
thanks guys
Just cause wire resistance is in spec (should be less than 2 ohms) doesn't mean the wires are good.
They should be load tested with a head lamp bulb to see if they can carry enough current to light the bulb. Disconnect the ECU connectors and injector connectors. Connect a headlamp bulb wire to one terminal and the other bulb wire to ground. Then take a wire and jump from the positive terminal to the proper ECU terminal for the wire being tested. If the bulb lights up bright then that wire should be good. Repeat the test with the other wires.
If all the wires can carry a load like that then the ECU is probably the culprit. The injectors all get their power from the same fuse and the ECU controls the ground side for each injector.
They should be load tested with a head lamp bulb to see if they can carry enough current to light the bulb. Disconnect the ECU connectors and injector connectors. Connect a headlamp bulb wire to one terminal and the other bulb wire to ground. Then take a wire and jump from the positive terminal to the proper ECU terminal for the wire being tested. If the bulb lights up bright then that wire should be good. Repeat the test with the other wires.
If all the wires can carry a load like that then the ECU is probably the culprit. The injectors all get their power from the same fuse and the ECU controls the ground side for each injector.
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chris' speed 3
Greenie Member
I just asked him if he load tested the harness and he said he did it with his AVR and it checked out, not sure what AVR is tho
Glad you found the issue, and also sorry it is probably the ecu. Curious if a reflash from mazda would fix it. Might bs worth asking about it via phone or whatever with a local mazda dealership.
chris' speed 3
Greenie Member
my mechanic said best way to fix the ecu would be to buy a refurbished/used one and he's able to reprogram it with his scanner apparently will only take an hour or two
Maybe the first owner but I couldn't tell you. I know that they saw the voltage drop on the waveforms and it was a super slight drop they didnt notice it the first time they checked. But the voltage drops which means there's resistance somewhere in the circuit right
chris' speed 3
Greenie Member
What?
yeah he did it was on the first page pretty sure but there was no way for me to know that without checking everything else
Enki
Motorhead
My worm addled old man brain wants to remember something about there being an issue with the dealer trying to reflash an ECU that has some specific aftermarket tune on it, but I don't recall exactly what that might be.
There's no way I would call an ECU fault that fast, so I went and checked. Was actually page 7:
https://mazdaspeeds.org/index.php?t...mode-on-acceleration.15105/page-7#post-105193
The ECU flash issue was with the cpe stand back. They broke the computer that flashed the modules into the ECU and there was no way to remove them until they worked with Cobb to add that functionality to the access port
chris' speed 3
Greenie Member
Your right u didnt say ECU but it is indeed 2 injectors down sorta
I just hope that they tested all the wires properly and the ECU does actually fix the problem, this whole thing is like 99% sure because of the p0202 code i had must've damaged the circuit or smt
One thing about making good power again is it could be hard on a half good engine. Hopefully it works well for a while though!
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