Check fuel filter. Check that the fuel pump release valve isn't stuck open (heard of this quite a lot). Also check that the pressure side of the fuel pump line (in the tank) isn't torn. This caused the exact same problems in my friends DSM and he chased it for a few months. When he pulled the tank he was greeted by a ripped 3" rubber line that was only about a year old.

On the evo you have two fuel pump speeds from what I've read (and you can hear it when driving around without your rear seat in). I'd be checking to make sure your getting a full 14+ volts at WOT in the car AT the pump.

It would be worthwhile to get a mechanical fuel pressure gauge to tap into your fuel rail or on the output of the filter. No need to run it into the car, just sneak the line under the lip in the rear of the hood and duct tape it to the windshield so that you can see it. I've done this quite a few times (taping gauges to the windshield) and have even ran cars on the highway without the hood to check for other issues.

 

Here is something no one mentioned: fuel trims. When the car is on the dyno and you flash it the fuel trims reset on the Evo 9 (does not happen on the Evo 8). So the AFR reads lean on the dyno. When the customer took his car and dorve around, then the fuel trims became positive and the ECU added fuel during WOT operation aming the AFR rich and then lean. This is the same way my car used to behave when I first flashed it and after I drove it around for a while. After I re-scaled my stock injectors to 472, the problem was solved.

Just thought I would add my 2 cents

 

The fuel trims don't add fuel at WOT open loop conditions.

 

Chad,

I did fill the tank up when I left the shop, and thats when I started doing the pulls and looking at my AFR's on the AEM...

 

On my drive back to NY, I noticed 2 things about my wideband...

1. When I turn the car on, the wideband displays "P00"
2. As I was warming the car up, it displayed "U05"

Anyone know what these codes mean? I dont have the manual that came with the wideband...

Could it be that the o2 sensor is fouled and showing AFR's that are off?

EDIT: Spoke with Chad, and my AEM and the his readings were pretty much identical..

Id still like to know what those codes mean though

 

"poo" *giggles

 

doh yeah lol

 

On my car they do

 

so, i guess the car needs a retune now because its running pig ritch?

 

Just got a call from a friend with the same problem. Can't go richer than 12's. Evo IX, downpipe, testpipe, catback, intake. Then I realized looking at his log when it was 70 degrees out and he was at 90% duty cycle at 22psi. With this colder weather he's just out of injector. This car is probably the same.

What power did the car make on your dyno. I was at a little over 300whp and 315 on your dyno nov 3 and on the edge of being out of fuel on a stock IX w/catback and MBC. At 310whp I wouldn't be pushing stock injectors at stock base fuel pressure any more on your dyno IMO!

You can do the math and you have 20ms to inject fuel at 6000rpm's. At 16ms that is 80% duty cycle or the safe recommended limit. 90% and your pushing your luck. Low quality injectors tend to saturate or just fail (the coils overheat) at this point. If your at 100% then we call you a DSM'er too poor to afford the right parts LOL!

 

i tuned a car the other day making about 340/320 and he was at 98% as well.... kinda strange

 

being overly rich will induce high IDC's too are you guys a little fat with the fuel?

 

...

 

Thats why I specified on chads dyno. I personally had my car on it and know about what kind of hp the average evo IX is going to support on stock injectors. Its a simple problem, just slipped my mind. The customers car has too many mods for the injectors, very simple actually. Gonna have to turn down the boost in this colder weather with denser air.

Mellon, you should know I'm the black sheep supporter of running lean. I shoot for mid 12's on my personal cars...........

 

whoops, it seems I had a senior moment