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brownieS15

SR20DET Blacktop flatspot/hesitating/surging issues

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Hey guys,

 

Recently put a SR20DET black top out of a 180 in my na s13, anyways was running ok for a bit at the start a little bit of surging on minimal throttle fine under boost, anyway problem has developed flats spots hectic bad and surges at partical throttle around 2500ish rpm hits boost is fine at back off boost starts again its intermittent but happens probably once a minute, now and then will flat spot when planted foot then hit pick up and hit boost, checked all intercooler hoses and vac lines all ok, have removed EGR also as running 3" stainless turbo back exhaust (blocked off egr vac hose), i run it on 98 and have removed and had injectors professionally cleaned, changed fuel filter and cleaned fuel pump sock, still running stock fuel pump also (from the na), only mods are BOV and 3' inch stainless exhaust, also found when i was removing injectors that once of the little silver washers that sits on top of the rubber piece in the injector holding in cap thing was missing just wondering if it is brutally important? cheers

 

Mick.

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Did you preasure test the cooler/vac pipes/lines ?, thats the best way. Next change that 20year old na fuel pump. If thats not causing the issue now, it will give you grief sooner rather than later. I would also check your knock sensor and O2 sensor. Is it ok when cold and turns to shit when warm? then check the ecu temp sensor. I take it you have the matching ecu for the engine? and your not trying to put fully hectik boost preasures through it. If you have the boost wound up, put it back to stock boost and see if that improves things. You don't mention if it's blowing any smoke.

Edited by Moneypit

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nar will do that, visually inspect or inspect via scan tool? or both? it faults anytime cold or hot doesnt matter, idles fine boosts fine just at partial throttle plays up, yeah is matching stock ecu and is stock 7psi boost, and its not blowing any type of smoke

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Fuel filter could be stuffed check that and as said before change the fuel pump if it isn't dead it will die soon enough

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righito going to grab the vac tester from work tomorrow and swap out my fuel pump with my brothers 040 out of his gtr lol and see how i go

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If it's only on part throttle try unplugging the O2 sensor and see if that makes a difference.

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If it's only on part throttle try unplugging the O2 sensor and see if that makes a difference.

 

narrowband O2 isn't in closed loop on throttle transitions..

 

I would think it's more AFM or Fuel pressure related

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mine does a similar thing. bogs down off the line, the boost level keeps going up with no power gain and then the ECU decides to add fuel in around 3k and you hit warp speed.

 

I am assuming its a fuel pressure issue as it happens most frequently around half tank or less, but i am guessing.

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Havnt swapped out pumps yet but tested all vac lines for leaks, found my BOV holding no vacuum, going to swap with stock bov (holds vac tested) tomorrow and swap fuel pumps over and see how she goes, anyone recommend reinstalling egr and see if it makes a difference or nar?

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When my TPS went bad it had all the same issues you are describing.

 

Check the voltage of the TPS via the consult cable or a multimetre.

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This seems to be the best design of the Nissan models and people are obtaining it with full enjoyment. Thus you can visit pay to write a paper so that they will guide you according to your own demands and choices.

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