Jump to content
SAU Community

Recommended Posts

Hey guys and girls,

I have recently converted my R34 Gt sedan from an RB20DE to an RB25DET Neo from a GTT and converted it to manual. We have kept my standard r34 de afm which we believe is the problem.

We have started the car and it drives like a dream untill you plant foot and it starts to boost.. Basically we have worked the actuator hoses to run a constant 8 PSI which is standard of the actuator? am I correct? Which is cool but when we try to boost it boosts up to and sticks at 5 PSI for about a 1000 rpm then it cuts out. We have connected this to a diagnostic tool and at the exact second that it cuts out the injector cycle dies and gives an afm voltage of approx 4.7V Which is right on the verge of maxing out....Please feel free to correct me if I am wrong...

Im just wondering would the afm maxing out cause the ecu to cut the injectors and cause it to only run 5 PSI?

Can someone who has an R34 GTT with an 25DET in it please inform me as to the colour and numbers located on the AFM. I believe they are pink but the numbers may be diffrent.

Or is there another issue causing this that we may have overlooked....

Any help would be greatly appreciated.

Cheers,

Link to comment
https://www.sau.com.au/forums/topic/306209-r34-injector-cut-afm-issue/
Share on other sites

Neo AFM part number will either be 22680-31U00 or 22680-31U05. i'm sure all Neo's weather being turbo or N/A will use the same AFM, i have checked this in FAST before.

You should check what Trent said, the stock Boost Sensor. It will detect an overboost and cut the engine they way you describe, or if it isn't hooked up will through an error code on the ecu. i haven't tried it but this error code may cause the ecu to run in a safe mode and cutting the engine before you load it up too much. and having done a conversion, it could be something that was overlooked?

My AFM is 22680-31U00 like you said... and Im pretty sure the sensor has been connected but it wont even boost to 8 PSI like it should do??? It goes to 5 PSI on the dot and wont move past even after sitting there for 1000 - 1500 rpm before it cuts out completely...so could it still be the sensor? would that not mean it would cut out above say 12 PSI where it would normally go to 8 PSI with ease

Cheers

yes, if the boost sensor is connected you will hit a cut at about 14psi. one thing, i have a RB25 NEO in my Stagea. on the Stagea the standard wastegate is 5psi, with a stock boost solenoid bleeding off to 7psi once you hit about 3500rpm (i cant remember the exact point). I think the R34 is the same, someone will correct me if i'm wrong though lol. Have you used some kind of boost control to get 8psi?

Edited by QWK32

I am not the one putting the motor in but i just had a bit of a look around it and it is actually an RB25DET NEO out or an C34 Stagea...So that makes sense only getting to 5 PSI. I was told they were 8 but i guess not. The loom has been re wired to accomodate my motor and my afm only has three wires and yours has 4...Is that my problem then...Do I have the wrong afm?

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


  • Similar Content

  • Latest Posts

    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
    • Probably not. A workshop grade scantool is my go to for proper Consult interrogation. Any workshop grade tool should do it. Just go to a workshop.
    • In my head it does make sense to be a fuel problem since that is what I touched when cleaning the system. When I was testing with the fuel pressure gauge, the pressure was constantly 2.5 bar with the FPR vacuum removed. When stalling, the pressure was going up to 3.0 bar (which is how it should be on ignition).
    • ECUtalk pages don't mention they support the ABS computer (consult port has more than one CAN), so you might just need a different scan tool. But, I would expect ABS is a different light to the brake warning/handbrake light, do you see an ABS light come on for a few seconds when you turn the key from ACC to IGN? But since you said: I'd have a look at the ABS sensors in the rear hubs to make sure they are not damaged, disconnected etc.
    • OK, if it idles at 1000+ with the AAC, its not an idle airflow problem. The cold start valve just gives extra air when the engine is cold, but you have enough air without it to idle at 1000. I think you are back to a fuel problem, sorry. Can you see the fuel pressure staying constant or does it drop as the revs drop to a stall?  
×
×
  • Create New...