Jump to content
SAU Community

Rb25 Still Overfuelling!

wlspn

By wlspn,
in Engines & Forced Induction

 Share

Recommended Posts

wlspn Proficient

wlspn

Posted
Posted

Have written a few threads about this recently & Im sure some of you are sick of them but I need to try & find an answer... Had no car for months!

My RB25 is badly overfuelling on idle & all through rev-range. Injector pulse at idle is 7ms! Have no vacuum/IC leaks, have tried other AFMs & temp sensors, all with no luck... 1 interesting thing is I was told to unplug AFM & see what happened... While unplugged, the idle stopped hunting & exhaust stopped smoking, however you could smell it was still a bit rich. When I plugged AFM back in & went to rev engine, it was still in limp mode. I turned car off & on, same thing... Eventually with AFM plugged in I wiggled the wires & it came out of limp mode. It seems even moving where the AFM wiring meets the main loom has some effect on idle, (in & out of limp mode) but still nothing perfect. Does this give anyone any ideas? (bad earth from ECU to AFM, etc...) Really going crazy!

Any help appreciated

Link to comment
https://www.sau.com.au/forums/topic/294411-rb25-still-overfuelling/
Share on other sites
W0rp3D Grand Master

W0rp3D

Posted
Posted

I had a bad afm, the solder on the connections inside the afm from the plug had broken, another problem could be that you have a short in the plug its self, try another afm and see if it makes a difference.

femno Grand Master

femno

Posted
Posted
have tried other AFMs & temp sensors, all with no luck...

How do you know the injector pulse time at idle?

Check that you have supply voltage (12V), continiuty of the signal line to the ECU, and check the ground(s).

wlspn Proficient

wlspn

Posted
  • Author
Posted
How do you know the injector pulse time at idle?

Check that you have supply voltage (12V), continiuty of the signal line to the ECU, and check the ground(s).

Had short use of a scantool to check live data...

So supply voltage to ECU. Signal line from AFM to ECU? & does anyone know which pins in ECU are earths? Have a pin-out but unsure of accuracy...

wlspn Proficient

wlspn

Posted
  • Author
Posted
How do you know the injector pulse time at idle?

Check that you have supply voltage (12V), continiuty of the signal line to the ECU, and check the ground(s).

Checked all this today, came back fine... Every test I do comes back fine although there is obviously something wrong...

Any chance ECU could be at fault? Or anyone have any other ideas?

wlspn Proficient

wlspn

Posted
  • Author
Posted

Thats what Im starting to consider... Possibly a fault in the ECU itself. If it is thats fine, ill go get a Z32 ECU tuned to suit by Dr Drift or similar but if its not I dont have a clue what to try next

W0rp3D Grand Master

W0rp3D

Posted
Posted
Thats what Im starting to consider... Possibly a fault in the ECU itself. If it is thats fine, ill go get a Z32 ECU tuned to suit by Dr Drift or similar but if its not I dont have a clue what to try next

If you in the frankston area i have an ecu here you can try to see if it is the ecu.

W0rp3D Grand Master

W0rp3D

Posted
Posted
Thanks heaps mate but series 2 engine so possibly some difference in ECU... Seriously appreciated though

I believe S1 and S2 are the same, you can use the same model power fc on both, i believe the differences are outside the ecu, like the coils, S1 have an igniter for all 6 coils but S2 have an igniter on each coil, the ignition from the ecu is the same on both though, maybe do some searching and see what you can find, iys here if you need it.

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

    • The Bogan
      Torana Lx Gtr Hatch, Lots Of Pictures

      By The Bogan · Posted

      LOL, when one "money pit" is never enough Noice, and excellent work mate
    • The Bogan
      NC MX5

      By The Bogan · Posted

      I have more than enough digging, laying blocks, moving gravel, airrating, feeding and top soiling the grass, and setting up the veggie gardens growing some seedlings,  and then removing all the unused rock to keep me busy for the next few months at least,  hopefully the rain stops soon so I can get a few hours in this arvo, but, before that Sunday is washing day, is every body happy, you bet your life we are Nice country road day drives are a day off whenever I'm muscle sore from all the landscaping at the moment, but, more epic multiple day drives will start once the majority of the big jobs outside are completed
    • MBS206
      NC MX5

      By MBS206 · Posted

      I hear that would involve some nice country road drives into the hills for Mark...
    • MBS206
      Recommendation for engine oil funnel spill free

      By MBS206 · Posted

      I thought I'd come back and add something I JUST learned. A Toyota LandCruiser with a 1HZ, mates perfectly with a bottle of Nulon brake fluid. As in, it perfectly screws in. Great make shift funnel when you cut the bottom of it off. This may work for your Corolla.   Unfortunately, tipping a 10L drum is much harder than a 4 to 6L bottle, and they no longer include the easy pour tap which was just perfection to use previously.  
    • EndZee
      Fuel Pump Control Module & Dropping Resistor

      By EndZee · Posted

      Guys since i bought r33 gts25t coupe 1994 automatic a/t(manual swap 350z gearbox)  all i got is problems, always problems. Lets start with that when i turn key into ignition(ON) fuel pump doesnt always works. Sometimes i have to turn key twice Off/on/off/on until it primes. Its new, dw300 - 340lph. My gearbox broke so i did gearbox swap, install different intake manifold, injectors and i take pipes. Car was sitting in garage for more than half a year. I did assembly all not that long ago and when i turn ignition cant hear prime. All of sudden it stopped working. Theres many videos on YouTube how to make relay mod on r33 straight from battery so i did and it doesnt work! 😰 30 - battery positive  87 - positive from fuel pump to relay 85, 86 - one of two wires from original fuel pump wires(light blue, grey) and it didn’t work. so I check on ignition and took original BLUE relays wires from trunk, next to fuses. (I believe it’s IGN+ and ECU pin 18. it didn’t work…  tried connecting (IGN+ from og relay) and (ECU 104 from 1of4 FPCM wires) to my new relay 85/86 and it didn’t work.  I unplug FPCM. Didn’t work. im thinking what’s wrong   fuel pump is working, if I leave IGN+ on 85 and 86 straight to ground it works but it’s just nonstop. Since it getting constant 12v after key in ON. light blue wire gives me 6-8v.  so how this should be connected? What causing ECU not giving — on pin? Or I did sth wrong and that’s why it doesn’t work? I need negative signal on ECU that control fuel pump. What this should be?
×
×
  • Create New...