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Thread: Mystery issue, any ideas please?

  1. #21
    Head Mod Scottie's Avatar
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    We can hear the turbo spinning up so now that is working so the pressure test is a good idea, as you say the air going past the airflow meter must be going somewhere, and not in the engine.

    It's a Z32 AFM so can I use a multimeter to see rising voltage on a signal?

    Chris, car starts but flooded once when we left it overnight and tried to start to move next morning. All cylinders flooded equally, had to get vacuum pipe in there and crank it a lot, heaters on plugs etc.

    The SAFC2 is just monitoring at the moment, although I am thinking it must have some connection to the ecu to know the injector duty % it shows, is there a single cable it uses to adjust, how does it manipulate the signal?

    Another thought it that is has an aftermarket recirc dump valve, maybe a SARD R2D2 or whatever, if this was faulty could that be leaking boost out?

    Thanks very much for all this help, trying to get the s14a ready to put some miles on it
    2004 - on : 1999 S14a 398bhp 378lb/ft
    2010 - on : 2007 RX8 PZ
    1998 - 2004 : 1991 S13

  2. #22
    Head Mod Scottie's Avatar
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    Quote Originally Posted by sx rider View Post
    All the coil packs ok?
    We have done the test where you turn it over with coils and sparks on the top of the engine, and all plugs spark, is this sufficient or is there another test?

    Could a faulty CAS contribute to this, and someone also mentioned amplifier but I don't understand how these work.
    2004 - on : 1999 S14a 398bhp 378lb/ft
    2010 - on : 2007 RX8 PZ
    1998 - 2004 : 1991 S13

  3. #23
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    Have you checked the arch loom?
    AT-R website opened! Visit: AT-R


  4. #24
    Head Mod Scottie's Avatar
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    https://www.facebook.com/pg/Nissan20...=page_internal

    If you look at visitor posts have uploaded a short video from last night of how it is running.
    2004 - on : 1999 S14a 398bhp 378lb/ft
    2010 - on : 2007 RX8 PZ
    1998 - 2004 : 1991 S13

  5. #25
    Head Mod Scottie's Avatar
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    the more I think about this, the question I think that trumps all others, is why is there no boost measured from the turbo. Even with sensor, ECU, wiring faults and so on, that would still not explain why there is no boost even though I can hear the turbo spinning?
    2004 - on : 1999 S14a 398bhp 378lb/ft
    2010 - on : 2007 RX8 PZ
    1998 - 2004 : 1991 S13

  6. #26
    Guest hooky's Avatar
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    I know Others have said it but this is almost definitely a huge Boost Leak!

  7. #27
    I <3 BBS LM Actual_Ben_Taylor's Avatar
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    Will the SAFC display AFM voltage?

  8. #28
    Oor Willy sideways14a's Avatar
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    Any chance the turbo shaft has snapped? naa, its a boost leak innit..


    Come on give me a boost leak.. first of 2019, and first for ages!!!

  9. #29
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    Quote Originally Posted by hooky View Post
    I know Others have said it but this is almost definitely a huge Boost Leak!
    When we do the smoke test and leave the machine running for at least 5 mins no smoke appears out now though.

    Quote Originally Posted by Actual_Ben_Taylor View Post
    Will the SAFC display AFM voltage?
    Good idea, the SAFC2 does show the injector duty cycle which says about 1 to 2% on idle.

    Quote Originally Posted by sideways14a View Post
    Any chance the turbo shaft has snapped? naa, its a boost leak innit..

    Come on give me a boost leak.. first of 2019, and first for ages!!!
    We did think has the turbo shaft gone, as it could be the exhaust wheel we hear, but then we thought if the in wheel was not spinning it would not be running so mega mega rich as the afm would not be monitoring the air.

    We are going to do some more testing Friday night, i'll ask for another smoke test and pressure if we can, because when i look at the AVCR boost gauge it keeps trying hard to get above 0 psi and then they needle keeps getting to about 1psi and dropping to zero very quickly and repeat.

    Does the AFM know the direction of air over it? Reason i ask is if a faulty recirc valve dumps any boost which goes the wrong way over the afm would it fuel for this passing air as it does not see the direction?
    2004 - on : 1999 S14a 398bhp 378lb/ft
    2010 - on : 2007 RX8 PZ
    1998 - 2004 : 1991 S13

  10. #30
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    Could be worth taking the turbo inlet off (the 2 bolt thingy) and giving the shaft a wiggle and spin to see if there's anything not right there.
    My old S14a had a seized turbo when I got it and that used to run so rich because the ECU couldn't figure out why it had no boost so it just threw more fuel in.

    Sent from my SM-G950F using Tapatalk

  11. #31
    I <3 BBS LM Actual_Ben_Taylor's Avatar
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    In that case definitely try blocking off/removing the recirc

  12. #32
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    Sound to me like the ecu is cooked and there is a fault with the injector drivers or the loom is damaged and are grounding the injector wires and there being held open
    You could try unplugging the injector connectors and priming the pump and see if the engine floods if it doesn’t then unplug the ecu connector and plug all the injectors back in and see if it floods

    Can you make up a test lamp for the injectors something like a halogen sidelight should work and plug it into the injector looms and see if they flash or stay in full brightness

    I’d remove the safc completely from anything fuel related and check the voltage output of the maf directly google it for expected voltage outputs

    You can check the cas but that’s more involved

  13. #33
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    its been a while since I actually drove mine but im sure they don't generate positive boost when revved when stationary.

    id go with massive boost leak
    knackered AFM (try giving it a clean)
    Fuel pressure issue

    you can check the injectors are firing by unplugging them and sticking a 501 bulb in their place.
    I normally whip the plugs out and waft a blow torch over the holes if I massively flood an SR20. blow torch the plugs then wack em back in warm.

  14. #34
    Head Mod Scottie's Avatar
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    UPDATE :

    Was on hold for a few weeks as I've been working away a lot.

    Have done most of the tests recommended on here, but still to no avail.

    Car has gone into Tuning Developments today so Mike and Nick can have a look at it, as they are much more talented than me and have proper diagnostic equipment as well.

    One item I need to source is spare S14a ECU though, any ideas for a good place to get a known working one of these from?
    2004 - on : 1999 S14a 398bhp 378lb/ft
    2010 - on : 2007 RX8 PZ
    1998 - 2004 : 1991 S13

  15. #35
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    Just to echo @green_rs13, you won't be able to build boost when stationary.

    Hope you get this sorted soon!

  16. #36
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    Quick update in case people search for these threads.

    I turned out to be ECU related, either the ECU itself or the H-Dev daughter board.

    Nick fitted a spare ECU I had bought, popped a Nistune into it and a base map for 740's and problem resolved. There also turned out to be some error codes from the Z32 AFM so had to replace that as well, but the root cause was ECU, so at least feel a bit better as that level of diagnostic was well beyond me.

    Car needs to be mapped up on the Nistune now, and a couple of small jobs before I can commute. However first it has to go up to DCMS as the fuel tank needs dropping to replace the pipes and let Graham do anything that it needs whilst it's out.

    I have set myself the challenge to have the car on the road before Brexit
    2004 - on : 1999 S14a 398bhp 378lb/ft
    2010 - on : 2007 RX8 PZ
    1998 - 2004 : 1991 S13

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