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Thread: same old issue keeps on coming up NEED advice

  1. #1
    Guest Hugh Janus's Avatar
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    same old issue keeps on coming up NEED advice

    yet again i've an issue where the engine is running lean.


    I've literally had enough of chasing my tail over this because it keeps on coming up almost on a year by year basis.

    I converted the car from my old 3a S14a so basically everything has been swapped over to a new shell, i then had to send it to a company because of a wiring issue who sorted that wiring got the car running properly...they then said it was running a teeny bit lean and did i want them to adjust fueling with my SAFC, i agreed, they adjusted, then a few days later the engine started to rattle, i spoke to mappers about it and someone mentioned "oh yeah i remember that one...the engine was really rattly" ...it had never rattled prior to that point.but lesson learnt

    I bought another engine very early spring.

    then about the same time i posted up about running lean again on the new engine and had been hitting 12's on AF then after posting, a kent member kindly lent their Z32 AFM which i plugged in went for a spin and it instantly hit 11.5.

    so i bought a brand new from Nissan Z32 AFM and the fcuker is still hit around 12's and only very occasionally it'll go to 11.5

    so ive replaced:

    Rubber fuel lines in engine bay
    fuel filter
    pump had been hard wired (by mappers)
    smoke tested and pressure tested the entire boost system, no leaks
    new Z32 AFM

    now weirdly last weekend i changed my air filter, didn't disconnect the AFM pulled everything free changed filter, then on way home max it would hit was 14 on AFR *****

    so i really do think this is wiring related , Norfy has suggested doing a continuity test from ECU to Z32 which I've yet to perform but is there anything i can test, check disconnect change or whatever, I'm getting really fcuking bored of this.

    also a side note, i did connect consult on saturday and wiggled wiring whilst car was idling and checking AIRFLOW, but in hind sight i probs won't see any issues sat there idling???! as in needs to be boosting?


    i really do need help or advice on this, and appreciate any input or suggestions


    **** wiring had effectively changed position
    Last edited by Hugh Janus; 20-11-2017 at 23:43.

  2. #2
    Guest mike85sx's Avatar
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    If you pull the plug on the afm will it go into default safe mode? Maybe look at your fuel pressure regulator maybe the diaphragm is weak and not holding enough fuel in the rail

  3. #3
    Guest Hugh Janus's Avatar
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    Quote Originally Posted by mike85sx View Post
    If you pull the plug on the afm will it go into default safe mode? Maybe look at your fuel pressure regulator maybe the diaphragm is weak and not holding enough fuel in the rail
    cheers dude, ill swap it out

    as far as i know disconnecting the AFM won't allow it to run

  4. #4
    Guest mike85sx's Avatar
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    Might also be worth putting a gauge on the fuel system to see what the pump is putting out

  5. #5
    Guest Hugh Janus's Avatar
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    Quote Originally Posted by mike85sx View Post
    Might also be worth putting a gauge on the fuel system to see what the pump is putting out
    had one for years, on idle fractionally over 3bar on idle

  6. #6
    Guest mike85sx's Avatar
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    I think off the top of my head the standard fpr is a 3 bar reg have you got an aftermarket one on there

  7. #7
    Guest Hugh Janus's Avatar
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    no, its the standard one never been changed

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    Guest mike85sx's Avatar
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    Sounds like time for a nice adjustable one

  9. #9
    Guest mike85sx's Avatar
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    Or even try the fpr from the injectors off my engine

  10. #10
    Guest Hugh Janus's Avatar
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    Quote Originally Posted by mike85sx View Post
    Or even try the fpr from the injectors off my engine
    yeah could to as i swapped the entire inlet over form my old engine to this one so have your original one there

  11. #11
    Guest mike85sx's Avatar
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    Quote Originally Posted by Hugh Janus View Post
    yeah could to as i swapped the entire inlet over form my old engine to this one so have your original one there
    Saves you spending any money

  12. #12
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    it would run with the AFM disconnected, just wouldn't rev over 2/3k.

    sounds like it just need remapping?

  13. #13
    I <3 BBS LM Actual_Ben_Taylor's Avatar
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    You sure the lambda sensor is reading correctly?

  14. #14
    Guest Hugh Janus's Avatar
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    Quote Originally Posted by Actual_Ben_Taylor View Post
    You sure the lambda sensor is reading correctly?
    as in the wideband?, this had crossed my mind whether the gauge was correct to be honest, and have enquired with someone about a replacement probe (AEM)

    edit: will be doing a test on it once o get get it on a ramp

  15. #15
    Guest Hugh Janus's Avatar
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    Quote Originally Posted by green_rs13 View Post
    it would run with the AFM disconnected, just wouldn't rev over 2/3k.

    sounds like it just need remapping?
    the 3a should run fine and did so for quite a while on my 14a, the tweak on the rollers was probably done to mask (not intentionally) the underlying problem which appears to have carried over to new er engine.

  16. #16
    I <3 BBS LM Actual_Ben_Taylor's Avatar
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    Quote Originally Posted by Hugh Janus View Post
    as in the wideband?, this had crossed my mind whether the gauge was correct to be honest, and have enquired with someone about a replacement probe (AEM)

    edit: will be doing a test on it once o get get it on a ramp
    Yes, I'd confirm the wideband is reading correctly first.

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    Could it be a misfire showing lean on the gauge or any leaks in the exhaust before the wideband

    Check the extra ground on the maf is connected to a good ground point

    Does the car feel any different or just the gauge showing lean

    Any leaking couplers or gaskets between the maf and turbo inlet

  18. #18
    Guest Hugh Janus's Avatar
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    Quote Originally Posted by autosri View Post
    Could it be a misfire showing lean on the gauge or any leaks in the exhaust before the wideband

    Check the extra ground on the maf is connected to a good ground point

    Does the car feel any different or just the gauge showing lean

    Any leaking couplers or gaskets between the maf and turbo inlet
    Already checked for leaks before lambda seems ok, I replaced the AFM ground as I saw there was some slight surface rust on the wire so chopped it all way back soldered new wire on, ground had all paint removed etc.

    The car feels sluggish and laggy, given it should be circa 350 ish my mates 300bhp BMW literally out runs me.

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    If you google it there is a chart for z32 voltage vs approx hp if you plug in the consult and get someone to watch the screen while you give it some you will see if the voltage is close to your expectations

  20. #20
    Guest Hugh Janus's Avatar
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    Good call, I knew about the voltage chart

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