R34 Injector Cut? Afm Issue?

[Raki_King]

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,

[blind_elk]

Which ECU are you using?

[Raki_King]

Im using a standard RB25DET Neo ECU which came with the motor

[STATUS]

has it got the factory boost sensor conected? sits behind the factory bov.

[JonnoHR31]

nissan afm's max at 5.1v

[QWK32]

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?

[Raki_King]

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

[QWK32]

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 January 31, 2010 by QWK32

[Raki_King]

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?

[QWK32]

nope, i also have 3 wires. stagea's use a pink label AFM which has 3 wires, with either one of those part numbers i listed before.