Hey guys,

2005 Evo 8 With AMS Full Exhaust/GSC 272combo/TXS Intake/TXS Utec/780cc Injectors/walbro 255 pump & 5K miles. I did have a Greddy-RS Recirculating which was immediatley replaced when I began noticing these issues.

I'm having problems with My AFR at Idle, this has begun in the past few days. It appears that it's gotten worse since then. Starting out at stoichiometric 14.7:1 and gradually building up to resting ~17.0 - 19.5:1 and sometimes higher, but only while at idle. While crusing and maintaining a load in the 0% column and less than 10% throttle it maintains the AFR like it should. AFR's when under load are what they should be.

It looks like it may be the front O2 sensor, but I'm just looking for some more input before I drop a big chunk of change on a new O2 Sensor. Could this be caused by anything other than the front O2 sensor? I've checked the post maf/pre-turbo area for any leaks and found nothing.

One thing I have noticed is that it seems my fuel pump is louder than I remember it being. Doing some searching on this issue I read about someone that had someting come unplugged on their intake manifold that was causing their fuel pump to work harder than it should. I've investigated that, and came up empty handed. It's definately not as loud as it is when it primes shortly before I start my cadr.


WOuld it be possible that there's an injector that's not firing, or clogged?
Here are some videos where you can see the AFR's getting high and then normalizing as soon as the tiniest bit of load is applied

Thanks
Brian

 

Since I moved it I will help you too. lol

From what I gather you have a wideband, do you have any way of looking at the stock O2 to see what it is reading?

 

Thank you for moving it to the right forum.

I do have a wideband but I haven't found a way that I can see the stock front O2 to see what its reading. I thoguht I could do it on the utec, but I've poked around in there and haven't found anything.

I have to goto mitsu on Friday morning and I'm hoping they can check it out and give me an idea as well.

Thank you.
_B