Jump to content
SAU Community

VQ25det A/F Learn 82%

DodoStag
 Share

Recommended Posts

DodoStag Rookie

DodoStag

Posted
Posted

Hey guys i need some advice/ help from the incredible brains of the import community please.

Ive got a 2003 Stagea VQ25DET and ive got an HKS OB-Link connected. My problem is lack of power, lack of boost (gauge hows 7-8?psi max) and a rough idle and if left to idle for a few minutes will stall...

Sitting idling the ob-link shows this20200606_123724.thumb.jpg.aaf86aa50e1e939a7092e30bbbf8a573.jpg20200606_123808.thumb.jpg.600ecc8ba8760d1aac20134d0d33502e.jpg

sorry for the hazy photos the glass on my cameras broken...

Its also has the fault codes P0100 and P0235.

Ive replcaed the AFM twice and had the codes cleared by a mechanic but has returned...

When it idles rough or stalls theres a strong smells of fuel coming from the car.

Also the exhaust seems to sound like theres a hole in in the exhaust but the sound isnt there all the time its intermittent...

Dont know if this is related at all but the fuel gauge doesnt show the correct fuel level..  

First off what does the 82% a/f learn mean plz???? Oh and that figure does not change!!! Idling or under load its always 82%

Any and all help would mean the world to me ive only had the car 6 weeks and still dont know what its like to drive a healthy M35 stag....

 

 

Link to comment
https://www.sau.com.au/forums/topic/480552-vq25det-af-learn-82/
Share on other sites
KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Please turn the photo round the right way.I am looking at my desktop and cannot easily turn the screen.

So far as I can tell that device is only reading the information that is in your ecu so if you do not have a wide band sensor it will not have any useful information about your AFRs.

So forget the device and go back to basics. Check your plugs, coils and look for boost leaks (as in test for boost leaks - they are not always easy to spot).

robbo_rb180 Grand Master

robbo_rb180

Posted
Posted

get hold of a scan tool or obd reader and actually check what the sensors are doing if voltage is stable or random. Bet it will be a failed O2 sensor and a leak near the cat giving odd readings.
An old thread for connecting to M35s
https://www.sau.com.au/forums/topic/280322-m35-obd2-or-is-it/page/3/

MrStabby Grand Master

MrStabby

Posted
Posted

Check for loose / leaky hoses, in particular the ones to the fuel pressure regulators. When they've hardened a bit with age the boost can blow them off. In mine, the fuel trims maxed out when i had leaks. If you can measure vac at idle, i'll check mine so you can compare.

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

    • Kinkstaah
      R34 Gtt Wheel Offset Advice

      By Kinkstaah · Posted

      Given by the sheer number of questions about offset, absolutely not. If you had the information formatted this way: Space from R34 GTT hub to outer arch = 100mm Space from R34 GTT inner hub to nearest suspension arm = 90mm. (making this up) Buying a wheel that was advertised as Enkei RPZ5 Diameter 18in Width 9 Distance to arch = 84mm Distance to suspension arm = 76mm 100% of people would know instantly if it fits. They would absolutely also know instantly how close it fits too, and no questions would need to be asked. You would know you would have 16mm from the guard and 14mm from the suspension arm.
    • silviaz
      R32gtr sputtering and stalling

      By silviaz · Posted

      Ah ok, for example for the apexi ecu I heard that it's pretty limited with the information it can give you. Also not sure why Nissan used the consult port over the obd2, what the idea there was.
    • MBS206
      R32gtr sputtering and stalling

      By MBS206 · Posted

      Diagnosing with and without is mostly the same. You need to know, as Duncan asked, and what conditions. Car hot, cold, idling, driving, if while driving what rpms, is when you're varying, or is it when held constant.   From there it's understanding what can be causing it. Starting with pretending all of the sensors are correct. Which means if it's going rich, why would it be thinking more air is going in than it is, and under what conditions. So things like if only when under boost, it could be be a loose intake piping joint. It's just understanding the system, and understanding when/how the problem occurs, and then if it's only occuring in specific scenarios, what can be causing it.   ECU specifically, if it's aftermarket, it'll have software you can use, for the Skylines on factory ECU, there is Nissan Consult you can use. Most ECUs have a way to get data from them.
    • silviaz
      R32gtr sputtering and stalling

      By silviaz · Posted

      How do you go about diagnosing ecu's that don't have data logging, is it more experience at that point and just trying out things that you think will fix the issue?
    • MBS206
      R32gtr sputtering and stalling

      By MBS206 · Posted

      Stock O2 are basically useless beyond anything at stoich. Any misfire will also be seen as lean. The stock O2 also read a collective exhaust gas volume, not each cylinder. Sputtering and missing means not each cycle is firing, and some are. Which means even if rich, as shit, on cylinders as they miss, they'll read lean, but the cylinders that did fire will read rich, and combined, well, they can read anything from rich to lean.   Start with the basics before even going looking at sensor values.   Edit: I say the above, and that's coming from the guy with a few thousand dollars worth of scan tools sitting right beside me right now that I use frequently for my job.
×
×
  • Create New...