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Thread: Could it be Fuel cut?

  1. #1
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    Angry Could it be Fuel cut?

    When driving along in any gear put the foot flat everythings fine. starting in 1 or 2 put in through the gears changing at 6000rpm after the second gear change, it starts to surge ( power off and on not jerky a soft surge).. usually 4 sometimes 3

    Any thoughts? fixes?

  2. #2
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    Sounds like it could be fuel cut mate....im sure ive heard of others having this problem. Investing in a Dash hawk will give you fuel pump pressure. Maybe take it back to where it was dynoed & see what they think.

    Good luck.

  3. #3
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    Yep, borrow or buy a dashhawk.
    Either that or it could be KR (Knock Retard).

  4. #4
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    OK thanks, how to cure it?!

  5. #5
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    Might need a new fuel pump (or upgraded internals) or maybe a tune to streamline all your mods.

  6. #6
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    Just realised you have aftermarket turbo?
    Most likely boost cut...
    Have you got a boost gauge? What area are you from? Maybe someone can hook up their DH and do some logs.

    Id say most likely a tune as AD07 said - but without some logs its pretty hard to tell.

  7. #7

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    check all your clamps...

    it may be boost cutting if your spiking above 18ish

    but try step one first

    then get a dashhawk .. no questions.. just get one

  8. #8

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    6000 rpm??

  9. #9
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    between 4000-6000rpm

  10. #10

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    If its happening well up in the rpm register it could be the ECU timing settings moving progressively towards retard as an engine protection measure, possibly along with those other items (fuel and boost cuts) already referred to. A DH or boost guage will help you see if there are boost spikes. Do you have a stock ECU or a Standback or similar? If the latter, how is it set-up, especially wrt ignition timing and specifically wrt your aggressive (?) boost settings? This comes back to a retune to align all the mod's as suggested above.

  11. #11
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    it has a standard tune. will later have a tune... but if there was an easy fix i would like to do it now .. i knew a tune would fix it or find out why, but was wondering if someone had this before and it was something easy to fix ( boost leak, fuel leak, install a fuel cut defender or air leak etc)

  12. #12
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    NOTHING seems easy on these cars Luke.........

  13. #13
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    true that lol.. but no harm intrying

  14. #14

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    AD07, It's not specifically a Mazda issue but a common theme with turbo-charging, as there are many complex feedback mechanisms involved. For example, without wanting to hi-jack the thread, having upped my boost and added the FMIC and DP I'm generally very happy with my almost ballistic performance but still have an occasional compressor stall to deal with at high-boost-low-rpm settings, as the BOV doesn't dump all the boost backed up in the FMIC plumbing fast enough. It's not a huge issue just a minor irritation and I drive to accommodate it, managing my shifts so the stall doesn't get felt through the transmission. I'm not the only one stuck with this issue, I know.

    I'm contemplating a second BOV on the other side of the FMIC plumbing. But I did explore all the other issues being discussed here (fuel cut, boost cut, advance) before I figured out the cause of the problem, so I know what LUKE is going through.

    Your principle cause LUKE seems to be upping the boost, so you need to work from there. I'm sure it's ECU engine defence, and possibly fuel cut combined, in response to the extra boost. Can you get Mazda to retune it at your next service seeing you have a stock ECU?
    CP_e Standback & PNP; CP_e 3" SS Downpipe; Corksport FMIC with Top-mount K&N filter & OEM Ram CAI; Turbosmart BOV; Dashhawk; Prosport Boost Guage; JBR solid shift bushes; DBA 4000 Wiper-Slot front rotors; Hawk Ferro-Carbon HPS Street front brake pads (@ 69,000km); Sumitomo HTRZIII's in 225/45 x 18

  15. #15
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    its an option. its due for a service, i find it cuts back while in 4 mainly at about 4000-5000 when ur foots planted.. after reading up comments here im sure its a boost problem, due to the turbo boosting better tho still close to standard at 4500rpm + and better flowing exhaust.

    ---------- Post added at 03:01 PM ---------- Previous post was at 02:55 PM ----------

    boost cut, fuel cut, thtottle control/torque cut prevensions are all closely linked. and all 3 mods CAI, TBE, Turbo are setting these off lol dire need of a tune now
    Many want Power not many hold it long.........

  16. #16

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    It would be boost cut.

    You can fix it with either a piggy back like the standback, or you can buy a boost cut killer.

    See:
    http://www.mpsgarage.com.au/shop/pro...t-killer-.html

    I highly doubt you have hit fuel cut at 4000rpm...

    I will almost guarantee that if you put a boost gauge on it, if you put it in a high gear and load it up, then the boost will spike out of control till you hit a cut. Everyone thinks its fuel cut, but in fact it's boost cut.

    Just be careful, if you fix that and your car isnt setup properly then you will have bigger problems...

    My advice: slap a standback on it and get it tuned. Then you know exactly what's going on and there will be no surprises.
    CorkSport FMIC with Cold Air Induction, , Cork Sport Cat Back, CPE Standback with PNP, TurboSmart BOV, Custom Highflow Cat with CorkSports Downpipe,Pauter Rods, CP Pistons,ARP Head Studs, BIGGER TURBO COMING, Pre-ordered a Stage 3 CPE Engine.

  17. #17
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    I said boost cut
    Need a gauge or DH asap!

    If you are ever over my way let me know and we can make some logs.

  18. #18

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    Yep. I think the bigger turbo is the cue for this conclusion. Prime candidate is boost cut. Fuel cut would come in at higher rpm, and all these defenses including ignition retard will come into play progressively as you get closer to the red line if your foot stays planted.

    I agree that a Standback is a better option, so you can not only adjust boost but also schedule it, than simply trying to kill the boost-cut which, when all is said and done, is there for a reason.

  19. #19

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    I would not rule out load cut too... this ECU will look at absolute load, and if your new turbo is pushing the load envelope.. it will cut too...

    but as I said said earlier.. likely boost cut.. as 4th gear is not boost limited..

    easy soution is get yourself a GOOD manual boost controller.. and set it to 16.. no spikes.. no cut.. no nothing.. and no need to tune as its basically the stock boost level.. just without the spikes

  20. #20
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    i got a cut in 4rd gear today once again 4-5000rpm make once again changing hard 1st,2nd .......

    ---------- Post added at 07:26 PM ---------- Previous post was at 07:25 PM ----------

    SORRY WASNT 4th GEAR IT WAS 3rd

    ---------- Post added at 07:27 PM ---------- Previous post was at 07:26 PM ----------

    have not felt it in 5th yet prob cuz im off the throttle by than lol..

    ---------- Post added at 07:29 PM ---------- Previous post was at 07:27 PM ----------

    Tune next on list!!!!!!!
    Many want Power not many hold it long.........

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