Hey all,
I've been running my turbo setup for about 800 miles or so now, (was on vacation 4 a week), and I finally got my A/F ratio gauge working...
It reads from 10-17, and it works like it's supposed to, but here's my question...
Idling it will bounce from stoich (14.7) to 10 or less, it's pegged and stops at 10... so it works perfectly, no codes at all...
off throttle it stays around 15-15.5 (lean, where it's supposed to be) and when I'm off boost but still driving it stays at 14.7 like it's supposed too, here's the question:
When I hit boost it goes down to 10, meaning it is a rich mixture, and stays there all the way through the power band, this is exactly what my bro's VR4 did on his A/F guage in boost, but then why exactly do I need a high-flow fuel pump if the FMU supplies enough fuel already, according to the O2 sensor? If i am getting too much fuel, a VAFC will help lean it out for max power correct? (A/R of 11.5-12.1)
Thanks for the help guys,
Later,
Mike

 

It will help but be pretty ghetto.

If your A/F gauge is based off your stock narrowband sensor, it is useless for anything but entertainment value. You need to get a wideband capable of datalogging, so you know where to make adjustments regardless of what you use for tuning. I recommend a chipped ECU if you are on a budget or Hondata if you aren't.

 

Without a wideband O2 sensor, that A / F guage is just for show. You can get a good deal on ebay for a wideband, just make sure that the seller has an ebay store, or awesome feedback.

 

I know it's for show, but it's SHOWING me that I have a rich mixture....
I understand why I would need a wideband with datalogging so I know where to make improvements, but why would I need a wideband to tell me the same thing that the other is telling me, that it's running rich?? I don;t wanna spend $200 for something that's gonna tell me the same thing, that it's running rich under boost...
I would rather buy a VAFC so I could actually decrease the amount of fuel it's getting...
Thanks for the help,
Mike

 

A narrowband O2 sensor is worthless for tuning because by the time it reads what it does, the computer has already made adjustments. And it doesn't tell you how lean or rich it is running, so if you take too much fuel away, it could run so lean that it blows the motor.

You have already invested so much in the turbo, so why cheap out on tuning and risk a blown motor?

 

It is showing you that you have a rich mixture but it doesn't tell you how rich it is, so how can you accurately tune it? you can install a AFC or even an EMS if you like. But if you add or subtract fuel for your WOT fuel values it will still read 10AFR.

An AF gauge hooked up to a narrowband (NB) sensor only tells you that you are rich, it doesn't tell you how rich you are. A NB setup is not calibrated to the same accuracy as a wideband setup. So that means your actual AFR could be off by as much +/- 1-3 points from what the gauge displays.

If you had a wideband hooked up it will display precisely what your actual AFR is. It wont just say "10" or "14.7" like your NB setup would. It will say 10.1, 10.2, 10.3, 11.5, 11.6, 13.0 15.1, 15.5, etc etc. A wideband with datalogging doesn't just tell you where to make the changes. It will tell you exactly how much to change it by.

If you insist on tuning your turbo setup with using a cheap AFR guage and the narrowband sensor you might want to start saving up for a new motor or a rebuild. Here is some more stuff for you to read http://www.pgmfi.org/twiki/bin/view/Library/WideBandO2

 

Thanks for the info, but I'm pretty satisfied knowing that my engine is recieving a sufficient amount of fuel it needs in order to work on a daily basis...
I'm not looking for TUNING my car for max power, I'd rather save my money than spend another $500 or so bucks on a HEADACHE...
If the gauge reads "10" then, regardless of the actual A/F ratio, it is still below the Accurate operating threshold of the NB sensor, which according to your website link, is approx 14-15, which means that the engine is recieving enough fuel, albeit not the correct amount for MAX POWER...
So your quote about saving for a new motor is entirely wrong, because aside from pre-detonation and knock, more fuel will not hurt it...
Also, I noticed plenty of threads on here about how Uberdata and such things are difficult to tune, and after they think they have it tuned, it acts up again... I don't want a headache, i just wan't a semi-reliable KIT...
I live in PA, and I've asked about so called "tuners" in this area, but everyone around here are idiots, I know way more than any shop around here...
They are all audio-bullshit stores, they'll sell u an intake and maybe put it on wrong, LOL.

-Mike

 

Using the stock NB o2 sensor to tell you any vital information is just dumb and stuipid. The further you get away from stoich the less accurate the sensor is. So if your shooting for a 12:1 afr (like you should in boost) it will NOT give you an accurate reading. His comment about you saving for a new motor could be correct if you base your fuel requirements on what your NB o2 sensor is telling you.
I've experienced it first hand. When I swapped turbo's (to a larger one) my afr went through the roof. I knew this because of the way the car responded, but my afr gauge read that I was still lean. I corrected my problem enough to drive it to a dyno, strapped it on and leaned the afr out from 10.0:1 + to about 11.9:1. Still my afr gauge would read lean and rich when I know my afr was between 11.8 and 12.2 in boost.
It is not an accurate tool for telling you how your boosted engine is doing. You must have a wideband 02 sensor and meter if you want accurate reading.
Keep being stubborn and you will end up needing a rebuild, thats a fact. I don't know why you posted on here if your going to be stuck in your ways, and not listen to the advice being given to you.

 

First off, I'm not shooting for any particular AFR, as my original post was about the need for a high-flow fuel pump. I wanted to know why I would need a pump if my AFR was reading rich anyway. Just like every other post on this site, it turns out to be a "tuning" issue, where everyone says to get a wideband o2 sensor and tune with it...
1.) I'm not basing any fuel requirements off of my NB AFR guage, it's just saying it's running rich, which is what I want...
2.) I'm not running some HUGE turbo, it's quite small actually a T28 at 5-6psi.
3.) I love the responses, LOL, I'm stubborn because all the advice is the same, yet people have plenty of probs with tuning... I've read the posts about tuning...
I posted on here cause I want some good advice, which I have gotten, but the reason I'm not hell bent on getting all this tuning crap is because I DO NOT CARE ABOUT MAXIMUM POWER!!!! If the engine is running a lil rich, so be it, as long as it won't be ruined... And as far as you guys can tell me, the only major thing I'm really worried about is pre-detonation and knock...

Dude, I respect that you've done it before, but obviously u care about SPEED and TRACK competition, whereas I don't. Also, u say that kits are crap just because u can't tune fuel supply, but not everyone (aka most poeple) cares about tuning their fuel supply.
I understand in an optimum setup a great AFR is needed for max power and reliability, and when the money comes in I'll certainly get what I can to make it perform better, but for now, answer me this question:
Will A small turbo w/ FMIC on a daily driver, with a simple FMU running a bit rich, stock fuel pump or high-flow if needed, hold up to the demands?? So far it has run perfectly, no probs whatsoever.

The guys who have done the tuning thing, are all about it and they want everyone else to do it too, yet the ones who say they've used cheap fuel management (FMU) say it works for them fine, THAT'S why I keep posting, so I get a variety of responses, not just your response saying I should do this or that.

Thanks,
Mike

 

You come here asking for advice, but then you're going to go off and do what you wanted to do in the first place. Keep running it how you have it set up. Let me know when you post: 'There's this wierd grinding noise coming from my engine, and my car hardly moves...what gives?' so I can tell you that you should have listened to us in the first place. Have fun with that rebuild...hope you have a beater; you'll be in it.........alot.