So, with the following mods
-Perrin intake+inlet
-JMFab header
-Invidia O2 housing
-DC Sports downpipe w/ Mil.spec cat
-Perrin catback

and a tune, we're now here:



Some things of note:

-I'm in an autocross class where I can't directly control boost (creep is okay)

-Some similar cars with similar mods and the same autocross rules put down 280, 290 and 296 on the same dyno

-The long term fuel trim (low) has crept up to +10.16. From what I understand, when you flash an IX to tune it, it resets all the trims - so whatever learning the ECU has done is post the tune. So the car thinks it's running lean and adding fuel to compensate. (and I probably am not making 256 whp anymore.) From what I've read, this could be: bad O2 sensor, injector problems, vac leak somewhere, MAF, fuel pressure, coils... etc etc. No shortage of junk to look at. Chad did mention that the car was running really rich when it was stock, he even asked if it had an aftermarket fuel pump. (I'm 99% sure it does not as I've spoken to the previous owner - he wanted to do a bunch of stuff but couldn't). So I'm hoping I can fix whatever is causing that.

If anyone else has troubleshooting ideas, I am all ears!

 

I would check O2 sensor. I had an '02 T/A that started running rich, no engine code was thrown but after checking the O2, that was the problem.

 

the o2 sensor is only going to play a roll in fueling when running closed loop (idle and light load driving). When @ WOT you're in open loop and the ECU is using values programmed into the fuel maps... so I wouldn't worry about that.

I would check the simple stuff first; boost leak test, make sure the cat isn't clogged, anything rubbing that would cause the knock sensors to go off thus pull timing...

 

Am I reading correctly that your newest tune was only at 18psi?

For the 30 minutes that it takes, I would just pull the fuel pump and look at it to see if it's the stock pump, or an upgraded unit. I was also unsure about whether or not my pump was already upgraded when I got my car. Simple solution - pull the fuel pump and look at it!


On a positive note, you picked up 67whp from just a couple simple mods and a tune - that's pretty good. Wait until you add the CBRD intercooler, CBRD UICP and possibly a Walboro255 if you don't already have one!

 

This thing have an ebc or mbc on it yet?

 

No, he can't have a boost controller in his AutoX class...rocking 18psi at 3600 & all the way to almost 13psi at redline...haha...

 

Ah thx BJ, I re-read the top post on this page and found that now- that would explain the wavy torque though. Could one upgrade the WGA in the class or no?

 

The AFR's during that 256 whp run were 9.7:1 at 6000 RPM though - that's got to be costing me power, right? I get what you mean about the O2 sensor not being involved at WOT, that's a good point. It just means I'm rich for some other reason that does matter at WOT, right?

Reckanize stock boost control! Yep, them's the rules. The next class up = 285 Hoosiers, E85 and you start breaking **** left and right

Nope.

 

That is A LOT of taper, iirc boost should only taper to 15 or 16 on a stock evo....

 

have Chad do a boost leak test. You def should be holding more than 13 psi at redline.

Also replace the o2 sensor and then check the fuel pump. Replace with OEM since you are in a stock class.

Should be around 270-290 whp then on Chads dyno.

 

About the fuel trims... I'm pretty sure the long term fuel trims effect the open loop fueling. The STFT's do not, but the intent of the LTFT's is to shift the fuel map so that the STFT's average zero. Since all motors and control components are slightly different, this is (one of) the ecu's way of compensating for those differences without needing a custom tune for each car.

Do you have a wideband in the car? You should be able to reset the fuel trims (eg. reflash) with the car warmed up, do a wot run, drive around a while, then do another wot run and see if it is richer.

 

I can't get ECUFlash to hook up. I think the tune is locked and I need a 1.4 cable to unlock it (I have a 2.0, boo). Evoscan works though. No wideband but it's on the list for the offseason.

 

is MIVEC turned on?....., lol, just playing, yea what everyone else is saying, check the basics, im pretty sure the evo 9 still should be putting out at least 200 something whp, even on a mustang dyno, ugh, that sounds nasty saying "evo" and "190 whp" in the same sentence, its not a honda, should definitely be in the 200s at the least

 

Bump!

So - it's not a boost leak (see Chad's post above). The throttle body seals are fresh too.

Later, I had a compression/leakdown test done. The compression numbers: 150 150 152 155. In spec or a tick high... OK, nothing really wrong here.

Leakdown:
cyl 1: less than 10%
cyl 3: less than 5%
cyl 2: less than 10%
cyl 4: less than 10%

In cylinders 2 and 4 there was a little bit of a browning around the spark plug holes. The shop's guess was that the plugs had been overtorqued and exhaust gas was getting out. I found out later that the plugs HAD in fact been changed by the previous owner, who, shall we say, did not choose his modifications well, or demonstrate any mechanical ability. Now, despite this problem, the leakdown was still under 10%.. but I'm sure it's not good.

That's also when I found out about the fuel trims being +10%. (For some reason when I updated this thread to include the fuel trim stuff, I forgot to mention the compression/leakdown results, duh.)

Since then, I've done the following to troubleshoot (was going to do this stuff anyway for the most part):
* Lightly used IX coil packs
* New plug wires
* New coil boots
* Freshly cleaned IX injectors
* Cleaned MAF

After those changes, the little hesitation I had at 3500 RPM went away. But I've been datalogging with Evoscan since then, and the fuel trims are pretty much the same - the mid is right around zero, but the low is +10.

It's looking more and more like the spark plug leak is one of the problems.

I have a fresh OEM WGA waiting to go in too as it does seem like the car isn't holding boost to redline as well as others.

Anyhoo - open to suggestions, as usual!

So I have a wideband in the car now, yay. (AEM UEGO)

Watching it, the car seems to do a decent job keeping the car in the 14's when idle and when cruising so I would guess the O2 sensor is okay. I've reset the ECU (via battery, at least - which set the trims back to zero) but it seems to always end up the same.


If anyone else has ideas, please share. The goal when I started this was 300 whp in STU-legal trim - I don't know if I'll get there, but I'd like to get close!

thanks
john