Jump to content
SAU Community

Really Lean Idle, Upgraded Injectors R34Gtt

Bratva

By Bratva,
in Engines & Forced Induction

 Share

Recommended Posts

Bratva Community Regular

Bratva

Posted
Posted

Hi,

I have just upgraded injectors (nothing rly else that would affect anything) on my R34 GTT. I have nistune and so i changed the k constant by going through the injector resize option and changed from 725cc to 1000cc.

This brought the k constant down from like 394 to 285. Problem is my air fuel gauge shows about 20 on the gauge and it runs pretty choppy. If i move the k constant up closer back to 394 originally the AFRs drop down back to closer to 14.7.

But if i rev it just a tiny bit it jumps up again.

Any suggestion would be appreciative! Just trying to get the car able to be moved to the tuners 350km away.

It already had an existing tune and ran no problem.

Thanks :)

Moodles2 Grand Master

Moodles2

Posted
Posted

Injector latency is different even between same brand. An example is this pair (Denso made injectors). Sard 700cc 0.65msec, Sard 800cc 0.75msec.. so you can imagine the latency difference between 725cc and 1000cc.

rob82 Mentor

rob82

Posted
Posted (edited)

Bring you min injector on time up a little - they are probably be operated outside the non linear range of the injector... Unfortunately it is not an exact science... Especially when your not taking into account latency.

Edited by rob82
Bratva Community Regular

Bratva

Posted
  • Author
Posted

Hey guys yeah you were right thanks jacked the latency to 1030. Now its idling perfect at ~ 14.7 AFR and rest of the rev range looks good. Might read a bit more instructions next time ;) There wont be any damages having 20AFR on idle ? Also not having narrowband plugged in is also okay on a 350km trip ?

Moodles2 Grand Master

Moodles2

Posted
Posted

Narrowband sensors get damaged when they're not powered as the heater can't burn off deposits. It sounds like you're using Nistune, there's are afew ways to ignore O2 feedback, one of them is to set the minimum engine temperature which the ECU will accept O2 feedback (defaults at 30C) to something high 200C where the engine has no chance of getting that hot, this way they will at least be powered.

Bratva Community Regular

Bratva

Posted
  • Author
Posted

I have my wideband in its place at the moment, so its not connected at all or screwed inside the dump. I prefer to keep the wideband so i can monitor AFRs on the way there, also just read that i can solder some wires to the ecu to simulatre narrowband signal :O. Its MTXL Innovate one. Or since the AFRs are okay i can just plug in the narrowband so cruise is okay and hope not issues.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • MBS206
      NC MX5

      By MBS206 · Posted

      My guesstimate, with no real numbers to back it up, is it won't effect it greatly at all.its not a huge change in position, and I can't see the air flow changing from in turbulence that much based on distance, and what's in front of it. Johnny and Brad may have some more numbers to share from experience though.
    • dbm7
      Automatic Power Button Light Flashing

      By dbm7 · Posted

      Which solenoid? Why was it changed? Again, why was this done? ...well, these wear..but ultimately, why was it changed? Did you reset the idle voltage level after fitment? I'm just a tad confused ~ the flash code doesn't allude to these items being faulty, so in my mind the only reason to change these things, would be some drive-ability issue....and if that's the case, what was the problem? Those questions aside, check if the dropping resistor is OK ...should be 11~14 ohms (TCU doesn't throw a flash code for this) ~ also, these TCU designs have full time power (to keep fault code RAM alive), and I think that'll throw a logic code (as opposed to the 10 hardware codes), if that power is missing (or the ram has gone bad in the TCU, which you can check..but that's another story here perhaps).
    • The Bogan
      NC MX5

      By The Bogan · Posted

      Question for people who "know stuff" I am looking at doing the new intake like the one in the picture (the pictured is designed for the OEM TB and intake plenum), this design has the filter behind the front bar, but, the filter sits where the OEM duct heads into the front bar, and the standard aperture when the OEM ducting is removed allows the filter to pulled back out of the front bar into the engine bay for servicing, a simple blanking plate is used to seal the aperture behind the filter This will require a 45° silicone hose from the TB, like the alloy pipe that is currently there, to another 45° silicone hose to get a straight run to the aperture in the front bar Question: how will it effect the tune if I move the MAF about 100-150mm forward, the red is around where my MAF is currently, and the green would be where it would end up Like this This is the hole the filter goes through  Ends up like this LOL..Cheers    
    • Duncan
      R34 Plug Identification

      By Duncan · Posted

      Despite the level up question, actually I do know what that is....it is a pressure sender wire.  So check out around the oil filter for an oil pressure sender, or maybe fuel pressure near the filter or on the engine. Possibly but less likely coolant pressure sensor because they tend to be combined temp/pressure senders if you have one. Could also be brake pressure (in a brake line somewhere pre ABS) but maybe I'm the only one that has that on a skyline.
    • joshuaho96
      Automatic Power Button Light Flashing

      By joshuaho96 · Posted

      Pull codes via the self-diagnosis procedure. As far as I can tell this is just a sign of transmission issues but not a code unto itself.
×
×
  • Create New...