Unknown Ignition Cut/tuning Trouble

[-Jay-]

Hey everyone,

I'm currently in the process of tuning my car and am having trouble getting past 5500rpm. Or to be a little more precise, it won't go past 5500rpm.

Mod list:

Rb25det running on rb20 harness

Greddy Intake manifold

Q45 throttle body + rb25 tps

Greddy top feed 10.5mm fuel rail

GTR injectors with resistor pack

HKS 2535 Turbo (10psi internal wastegate)

Turbo back 3 inch exhaust

FMIC

Greddy Emanage Ultimate

Nimso AFPR

Sard r2d2 atmospheric bov

Bee-r rev limiter

So in any gear, any throttle position as soon as I hit 5500rpm, the car hits what feels like an ignition cut. (Feels like the factory speed limiter.) Its runs flawlessly before it reaches that figure. According to the logger, the ignition isn't breaking up and the air fuel ratio is fine.

Its not a boost leak, nor a coilpack problem, the maf seems fine its reading up to 5 volts so I don't see anything out of the ordinary there.

The guy that is tuning my car has a lot of experience with the emanage ultimate, he went on various courses to learn how to tune it so I think he is not at fault.

Checked for codes before and pulled up a 55, no malfunction.

If anyone has any ideas what could be going on I'd appriciate your input.

Thanks in advance,

Jay

[The Dan]

Wouldn't have anything to do with that Bee-r limiter would it?

And 5V is right on max for the AFM so it is also possible you are outflowing it. How much power are you making in KW at the wheels?

[nizmonut]

get rid of the BeeR limiter, the above picture is a result of using one of these limiters. it was in a week.

Rb20det_pinout.txt

i dont have a pinout for the rb25 handy, however if you do find one compare the numbers and description for the both,

you may want to check the tps and afm using different pins on the ecu's,

pluging the 20det loom into a an ecu designed and programed for a rb25 for example will missmatch these pins.

but 10 bucks says its the limiter.

[Adriano]

20 and 25 ecu's are a plug and swap arrangement, although you really should swap the two different injector wires(i think its 4 & 5)

[666DAN]

GT2535 10psi @ 5500rpm would defiantely be outflowing the AFM, but I would have though that the e-manage would be bending the signal enough that the ECU wouldn't see it as anywhere near 5v

[1C3B3RG]

I have similar problem. I have R33 gtst auto with electronic boost control, 11 psi, std turbo. Sometimes boost spikes ( for whatever reason) past 16 psi and wham! power cut, then ok again. Could be cold air, i have voltage bender to lower afm voltage so it does not max out. Still happens, i reckon voltage bender needs gentle signal increase. If its a sudden spike from say 0.5v to 5.5, its too fast for processor. This is all i can think of coz it's pissing me off to tell the truth.

[nizmonut]

thats cause the factory ecu's boost cut a 16 psi.

[-Jay-]

I removed the bee-r rev limitter so its not that, checked the tps doesn't appear to be that. Also retarded the timing a bit and that didn't help.

I'm going to wire in my z32 maf after work tomorrow and I'll let you guys know what I come up with. I wish I'd have bought an fcon, thats all I'm going to say.

[nizmonut]

I removed the bee-r rev limitter so its not that, checked the tps doesn't appear to be that. Also retarded the timing a bit and that didn't help.

I'm going to wire in my z32 maf after work tomorrow and I'll let you guys know what I come up with. I wish I'd have bought an fcon, thats all I'm going to say.

yeah, i was lucky enough to get my hands on a HKS Fcon pro V fuel/ignition system there brilliant,

every dynamic can be tuned at every 100 rpm interval, then it can self learn after that.

[1C3B3RG]

thats cause the factory ecu's boost cut a 16 psi.

Dude! I always suspected that, thank you so much for confirming that. I am not being sarcastic, just glad that the problem is diagnosed and not in the realm of the unknown anymore.

Happy times!

[Adriano]

thats cause the factory ecu's boost cut a 16 psi.

There is no boost cut, it would need a map sensor for boost cut. There is an excess airflow cut, which is a different boost for different turbos/modifications.

Edited May 13, 2008 by Adriano

[GeeTR]

get rid of the BeeR limiter, the above picture is a result of using one of these limiters. it was in a week.

Impressive

How have you theorized that the spark cut bent that rod though??

... Not being a cock, just thoroughly interested.

Edited May 13, 2008 by GeeTR

[aman1515]

try changing the ecu maybe its that.

[JonnoHR31]

25 pinout

[hypergear]

The cut is from Facoty rubber intake pipe sucking it self shut. I've had same issue before went to metal intake pipe.