How much power is the 465 good for?

 

I ran a dual setup w/a magnafuel 625 so i dont know

 

Thanks for fuel pump offers guys, if the new FPR and filter I ordered doesn't solve the issue that's going to be next on the list to swap out trying to solve this. And as su_maverick mentioned need to look into that test port by the filter. I did also find a post by Cobb Tuning clearly pointing to an FPR line popped off causing very similar or same symptoms, so at this point I'm still having a pretty strong feeling the FPR or maybe it's inner O-ring is the culprit.


I got the car with 32k on it not quite 2 years ago and at that point I believe all that had been done to the car was a new ignition switch and the new version of the stock bypass valves, so I don't believe anything on the fuel system has been touched. And pretty sure those were the original spark plugs I just took out.


The more I think about it though the performance of the car under boost has always kind of varied, sometimes a little more sluggish than others. So this issue could have been there since day 1 of me owning it and I only found it now by datalogging with the Cobb AP.

 

Good luck. Here if you need any help.

 

SamboTT@BYDESIGN is the man to buy COBB from...getting mine from him soon.

 

Are most using the standard OTS COBB tune that comes with the AP or going with a custom tune?

I have stock turbos, headers, exhuast and curious if I'd benefit from a custom tune over the standard OTS tune. Don't plan on making future mods at this point.

 

I am in the process of converting my 2003 996TT over to a Cobb ProTune. was very happy with my old tune, it was just that my shop couldn't "fine tune" the system. Im excited to see how it works out going forward.

 

Cheers everyone! It's a great tool as you can see.

P your map is on the way!

estoril, the OTS maps are pretty good on the 996 with just bolt-ons. I would be glad to look it over for you and walk you through it. Custom tuning works great to dial a car in that last custom bit or to calibrate for hardware changes.

 

As someone that's been working with Sam with the AP, he's been great. Answers at all sorts of hours, even getting me a map on Easter day no less!

 

I agree. Sam's responds all the time and even for things not related to your purchase. Great member of our community!

 

Ok, so yesterday started with swapping in a new fpr, and while I was in there zip tied the fpr line just for good measure. Still lean and short term fuel hitting 1.21-1.25 under boost and some knock. Next swapped in a new fuel filter and still same results. So I'm still scratching my head on this. I have no check engine light or error codes. Next options I see are continuing to look for boost leaks, try to comfirm fuel pressure. Did more searching and found mention of dirty MAF sensor causing lean by lower air count. Should i be trying to clean that and log again just to try and rule that out? Anybody have info on what the airflow should be at lower boost on stock turbos, or a log from a healthy car they could share for me to compare.

 

i wont be of much help but rememebr that stft are applicable on intial startup when the car is cold. after just a few minutes they arent relevent in terms of trim thats what the ltft are for

 

Ok, I seem to find mixed info on that also where some info for says that at WOT the ecu goes closed loop and ignores the O2s and runs strictly off the MAF, but then someone else stated the O2 and stft are still used. I can say for certain though the stft are still fluctuating in the loggging, and go heavy on the higher side when I go WOT and it transitions into boost and looks like the stft's are trying to compensate for the extreme lean being logged by the O2's.

 

You sure about that?

from my understanding, the pre-cat O2 takes the reading of the AFR and determines if the STFT needs to be adjusted and is applicable at any time during driving. The LTFT gives you somewhat of a base that accounts for things like normal wear on an older motor.


BTW Russ - A boost leak will not cause a lean condition but the opposite. Check the sensors to see if they are working correctly first

 

Check the intake tract post MAF but pre turbo. Anything drawn in not metered by the MAF is extra air and will cause a lean reading. Pressure testing that side might reveal any leaks but you can check the seals up top yourself. I once found a clamp on my MAF completely loose somehow and I'm sure it wasn't good. You might also try unplugging the MAF, this will put it into a limp mode but perhaps help you determine if the MAF is to blame without swapping it. I'm not sure how well it will log sans MAF but it's worth a shot I think.

Generally under WOT OEM ecu will go open loop and ignore the O2 but since the 996 has wideband O2 sensors I'm not sure if it does this. This is a pretty puzzling problem for sure. At cruise it has proper fueling?