Hi, have you met Lilith?

Discussion in 'Mazdaspeed 3 Build Diaries' started by Rokusek, Jun 18, 2021.

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  1. Rokusek

    Rokusek Are you my dad? Motorhead Platinum Member

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    Well, It runs kinda, the only issue now is she has the abs light on. Gonna have to drive it and try to get it to clear tomorrow. I am dead tired. gonna give her a go in the morning and see if driving will clear it.


    20240420_201755.jpg 20240420_215556.jpg
     
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  2. Raider

    Raider Administraider Administrator Platinum Member

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    No more fuel issues is good.
     
    Raider, via an iPhone, Apr 21, 2024
  3. Rokusek

    Rokusek Are you my dad? Motorhead Platinum Member

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    Woke up, came out to start the car, no start. cranks and wants to start then dies.

    The ABS U2023 is still there, the throttle pedal code came back and now fuel rail pressure is reading hit or miss, reset some connectors that i touched in the process of the injector swap, reset ecu, cleared codes fired right up with no issues, started to idle, then the ABS u2023 would pop, trip the p2122 throttle pedal position sensor low again, fuel pressure jumped to 0, she hiccupped a bit then calmed down.

    Went back and forth with this for a bit, checking fuses, sensors and tried two other throttle bodies and the pedal. At this moment, i cannot figure out why the p2122 is popping after the abs u2023 code then losing fuel rail pressure but not tripping the fuel pressure code.

    Over all right now, she is running at a clean idle, no longer running rich, fuel rail pressure sensor is technically working now, the will run and drive but in limp mode. I have a really hard time believing it could be the ECU or the harness or anything else i have replaced. I have fixed a ton of things but also still have these last couple bugs to figure out. I am starting to feel like I am starting to run in circles and cannot seem to get my bearings with this.

    I did get a log of this exact issue, I will get that uploaded shortly. After that I have things I need to take care of around the house then get back at it in a few.
     
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  4. Rokusek

    Rokusek Are you my dad? Motorhead Platinum Member

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    Internet went down and couldn't get these uploaded.
    Log 23 and 24 shows the pressure going to 0, that was the moment the ABS code popped up,

    log 27 is start up idle and loss of fuel pressure from the rail.
     

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  5. L337TurboZ

    L337TurboZ World Class Truck Squatter Silver Member

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    Try using a jumper cable to connect the engine to the negative battery post. It could be an intermittent ground issue or a bad cable. Using a jumper cable to act as a secondary ground cable could help isolate a weird grounding concern.

    Also try a loaded voltage drop test from the alternator post to the battery and from the starter post to the battery. An ideal loss across the cable should be less than 200mV.
     
    L337TurboZ, via a mobile device, Apr 21, 2024
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  6. Enki

    Enki Motorhead Platinum Member

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    I agree on potential for grounding or power issue; the car simply cannot run without some kind of fuel pressure forcing it through the injectors. You already replaced the rail sensor, correct?
     
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  7. Rokusek

    Rokusek Are you my dad? Motorhead Platinum Member

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    Yes, this would be the 4th sensor and only one of the four part numbers that even read proper pressure.

    Have gotta finish up some last minute things around the house then going to try @L337TurboZ recommendation.
     
    Rokusek, via a mobile device, Apr 21, 2024
  8. Enki

    Enki Motorhead Platinum Member

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    Smart test from L337.

    Kind of hard to tell from this photo, but I know that these things tend to be issues and I had a ton of cable left over, so I went ahead and turned the dial up to 11 for my wiring.

    Grounds:
    Dedicated head, body and I think starter cables, from battery.

    Pos:
    Dedicated alternator, starter and primary cables, to battery.
     

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  9. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    Does the battery have a full charge after all this dicking around
     
    Easter Bunny, via a mobile device, Apr 21, 2024
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  10. Rokusek

    Rokusek Are you my dad? Motorhead Platinum Member

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    yes, i have a trickle charger on it.

    @Enki and I just got done talking and video chatting. Verified spill valve is good, fuel is good. It is very weird what it is doing though.

    I send him a couple videos i'll upload here as to what it is actually doing. I am pretty confident that at this point I need to swap out the ECU. I have a VIN matched ecu and cluster, need to see if the BCM is still in the car those came out of. I might be lucky enought to not have to pay someone to reprogram, but i doubt it.

    So, calling a friend to swing over and reprogram the new ecu to the car.
     
  11. Enki

    Enki Motorhead Platinum Member

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    With spill valve unplugged, HPFP pressure is varying between 900 and 1600 PSI; this simply isn't possible with a confirmed properly functioning spill valve. I bet if you used some alligator clips and a multimeter, you'd see stable resistance across the rail pressure sensor.
     
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  12. Mtnbker3531

    Mtnbker3531 Platinum Member

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    I've also ran across the broken plug situation and it was when the Speed was still my DD. o_O I always have a spare set in the tool box now.
     
    Mtnbker3531, via a mobile device, Apr 22, 2024
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  13. L337TurboZ

    L337TurboZ World Class Truck Squatter Silver Member

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    Is it completely losing fuel pressure including low side pressure? Or only high side?

    Did you try the tests I suggested?
     
    L337TurboZ, via a mobile device, Apr 22, 2024
  14. Rokusek

    Rokusek Are you my dad? Motorhead Platinum Member

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    I wouldn't say it's physically losing pressure per say, something is causing the sensor to no longer read pressure. But the car still runs and idles once that happens. I have to grab my fuel gauge from work to confirm that physically again.

    I did use the jumper to see if that changed anything, with no change, I did not do the loaded voltage drop test. Logs read good voltage, After trying a jumper Enki and I deduced it is most likely the ECU. I did not go any further. I still can do the drop test. I also need a second set of hands to check at the starter.

    I have a full spare set in the car now and the still good 3 are in the tool box.

    Here are two videos I took to show a little more about what the car is doing.



     
    Rokusek, via a mobile device, Apr 22, 2024
  15. Mr Dangly Bitz

    Mr Dangly Bitz Greenie Member

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    Check for critters eating wires. Tommy had the same issue. Ran a new wire to the fuel pump and was all good
     
    Mr Dangly Bitz, via an iPhone, Apr 22, 2024
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  16. Raider

    Raider Administraider Administrator Platinum Member

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    I am thinking adding like 3 new grounds from the engine might help. Perhaps a visit from a priest to perform an Exorcism.
     
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  17. Enki

    Enki Motorhead Platinum Member

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    Yall don't understand; the spill valve has to be energized to make pressure. With it unplugged, the only pressure you can make comes from the ITFP. This makes it impossible to swing between 900 and 1600 PSI like it does.

    Also, the car can't run on 0 PSI. If it were PI, it might be more feasible for the mani vacuum to pull in some fuel, but not DI.
     
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  18. Mr Dangly Bitz

    Mr Dangly Bitz Greenie Member

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    i thought there was a check valve within the spill valve, meaning at an absolute minimum you get ITFP pressure.

    Reading zero in one video and pressure in another leads me to go electrical. either theres a dead sensor or damaged wire somewhere

    I hate electronics so thats about as far as i go. Tommy ended up pulling his fuse box and finding everything chewed to shit on the underside. Could be something in the harness if the sensors all check out. just my .02
     
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  19. Enki

    Enki Motorhead Platinum Member

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    Yes, you get ITFP pressure when the spill valve is unplugged, just like I said in the prior post.

    The only other thing I can think of is to meter the rail pressure sensor and see what it ohms out to and if it wavers enough to account for what is being seen on the AP. If it's stable, it's probably an ECU issue.
     
  20. Rokusek

    Rokusek Are you my dad? Motorhead Platinum Member

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    Trust me when I say this, this engine harness, engine fuse box and all wiring in the engine bay is 100% intact. I've spent the last four months making sure of that.

    The only possible wiring issue would be the rest of the body wiring or interior wiring. Which... Idk if any of that would cause these issues... Unless... Unless... the BCM is bad. Since the cluster, ECU and BCM all communicate together.

    I am hard pressed to believe it's the ECU, but with all the metering I've done following the shop manual. Its the only logical explanation at this point.
     
    Rokusek, via a mobile device, Apr 22, 2024

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