The car is an 03 EVO and it has the following mods:

Built forged 8:1 C/R
Stock heads with upgraded Springs and Ti retainers
Stock Intake Manifold
Stock TB
GT35R .68 A/R
Equal Length 321SS Exhaust Manifold
272/272 HKS cam
AEM Cam Gears
Turbo Smart Megasonic BOV
WasteGate
AEM Standalone
AEM 4 channel ignition
XC1 Coil on Plug
NGK Cooler spark plugs gapped at 25
880cc injectors
In-tank pump
Intercooler
KOYO Radiator
Full exhaust
HKS Turbo Timer
Stage 4 ClutchMasters
Alky injection
NX gen-2 Nitrous kit

The car never made the power I was hoping for. It made 395whp 276wtq at 21psi with alky injection on pump gas. It also made 460whp 380wtq at 29psi on Race gas. With 60shot and 19psi on pump gas it made 496whp 376wtq and 514whp 419wtq with 29psi on race gas and the same amount of nitrous.

Anyways the car was running just fine after I took it for a while. Lately it started to act weird. All runs are now made on pump gas with alky injection at 19-21psi to figure out whats the problem.
The problem comes when we get close to 19-21psi the car starts to cut and shakes and lose power. The AEM logs all looks fine. We checked A/F, Timing, Knock, Ignition trends, and also changes to new Spark Plugs gapped at 20 with nothing changed.
The strange thing is that after putting a silencer on the exhaust the problem went away, but the car still feels slow. We take the silencer out and the problem comes back again with the shaking and cutting at high RPM.

So what do you guys think is the problem?
Im thinking about two things now…
1- wastegate spring maybe, but the car is making the boost so that is making me say maybe not.
2- Valvetrain such as Springs or Rockers since the installer did something wrong before and broke few rockers and springs.
3- There is a white wire hanging down from the AEM!!! Im not sure what is that for?

What could hold back the car like this? Feel free to give me an ideas because i ran out of them.

NOTE: Dont tell me to take it back to the installer. Im done with him and his games.

Sorry for the long post, but i need help.

Thanks

 

You might pressureize your FMIC to make sure it doesn't have a leak. I have seen cars go nuts at mid/high boost and upper rpms dude to a FMIC leak causing the turbo to work really hard and you will never know until the leak gets so bad that the turbo gets out of its range and starts hitting the choke line.

If you car has been down on power for a long time it could of been leaking for a while and just now started to get worse. A good pressure test always helps with the process of elimination as well to check for leaks.

 

Thanks... I will check on that.


Anyone know whats the white line hanging from the AEM for?

 

WHO EVER TUNED THAT CAR NEEDS TO BE TAKE OUT BACK AND..... be taught how to tune. Way too low whp for that turbo and mods you have.

 

If you can get me the pin number the wire is from we can figure out what it is. It is hanging off the harness correct? Or is it actaully hanging out of the aem box?

ECU Pins
http://www.roadraceengineering.com/e...-ecuwiring.htm

 

Yes i know... It was Sean at Extreme Motorsport. It took them 10 months and 20K to give me a turd that ran good for 2 weeks and then it gave me these problems

 

Its hanging from the Box it self. I will check into that and post what i find.

Thanks.

 

have you done a compression check and/or leak down test? You may have a hurt motor.

 

The AEM ignition boxes are horribly unreliable.
They have redisgned them I believe because of all the problems they were having.
Try taking the box out and just running the COP and see how it runs.