ECMlink A/F ratio

[KeelesKustome]

Okay so I'm still dialing everything in, I'll post a log a little latter, my main question is why is my A/F ratio at 18:1 while driving?

under boost at specific rpm's it will hit my 14;7 target but it won'tystay their.

my global fuel settings are -45 for my pte 880's and my pressure is setup for stock, and of corse i am an auto.

I'm not recieving really any knock at anytime unless on WOT even then it only hits at 0.2- 0.4, but it's so fast you can only find it in the log, so it's nothing to worry about.

 

[GRAVEDIGGER]

Is your base fuel pressure set correctly, at approximately 42psi? 14.7:1 is too lean for being in boost.

 

[KeelesKustome]

ok so what does 18:1 mean?

 

[snowborder714]

Air-fuel ratio - Wikipedia, the free encyclopedia

 

[KeelesKustome]

^^^^
So that tells me I am running really lean. correct?

 

[snowborder714]

Yep!

Stock fuel maps at WOT run around 9.4-9.6:1 - very rich.
You should idle and cruise around 14.7:1.
You should aim to have your WOT pull to be around 11:1.

 

[dsmrollerz90]

This is kind of a noob question but I am in automotive classes and they say we need to be at 14.7:1. Why is this incorrect for boost? They tell me that this is the perfect A/F ratio, and if we go too rich then we can cause excesive carbon build up on valves and or egr valves.

 

[slow8033]

This is kind of a noob question but I am in automotive classes and they say we need to be at 14.7:1. Why is this incorrect for boost? They tell me that this is the perfect A/F ratio, and if we go too rich then we can cause excesive carbon build up on valves and or egr valves.

In a perfectly controlled world or environment you might be able to get away with boost at a leaner ratio than 11:1. But the world is far from perfect. There's bad gas, there's water in gas, There's gas you buy at 91 or 93 octane that is in fact 90 or below. There's to many differences in everday life to trust running a car at 14.7:1 under boost. Thats why the car is factory tuned to run at 9:1 or so... That way when something stupid occurs, you more than likely never know it.

The closer you walk to the threshhold of damage, the higher risk you have of falling off, even if it is accidently.

 

[dsmrollerz90]

In a perfectly controlled world or environment you might be able to get away with boost at a leaner ratio than 11:1. But the world is far from perfect. There's bad gas, there's water in gas, There's gas you buy at 91 or 93 octane that is in fact 90 or below. There's to many differences in everday life to trust running a car at 14.7:1 under boost. Thats why the car is factory tuned to run at 9:1 or so... That way when something stupid occurs, you more than likely never know it.

The closer you walk to the threshhold of damage, the higher risk you have of falling off, even if it is accidently.

True that. Thanks for clearing that up.

I hope this isnt too off topic but how can we check if our vlaves are carbon filled?

 

[KeelesKustome]

ecmlink is my tool, so what the heck is wrong for me to be so lean?

Should i lower my global settings from -45 to -40 and see what happens?

So i'm basically thinking my maf reading are wrong, and need to be fixed. uhg

 

[Jonnynitrous]

A engine absolutely can NOT run at 18 afr. at 15 afr it will start to miss. so your question should be"how do I set up my dsmlink" then you'll be on track. right off the hop you should set the global to the recommended setting in the ecmlink you do it in the fuel tab when you set up your injectors

 

[jrohner]

A engine absolutely can NOT run at 18 afr. at 15 afr it will start to miss.

Yes they can run that lean, not sure if you'd want to though.

This is kind of a noob question but I am in automotive classes and they say we need to be at 14.7:1. Why is this incorrect for boost? They tell me that this is the perfect A/F ratio, and if we go too rich then we can cause excesive carbon build up on valves and or egr valves.

But 14.7 is where it burns the hottest, and it's not where you make the most power either.

 

[Jonnynitrous]

Yes they can run that lean, not sure if you'd want to though.



But 14.7 is where it burns the hottest, and it's not where you make the most power either.

Um NO unless you have a 12 cyl missing on half the cyl you can NOT run at a 18 afr. please do not make me explain.
And NO once again 14.7 is not the hottest its the most efficient.
Efficiency is talking about gas mileage. NOT making power

 

[KeelesKustome]

okay so i think my maf is setup incorrect, and that is the main issue here, at idle it's reading .42 airflow per rev when it should be .25 ish, also my tps sensors voltage changed so i need to fix that/

 

[delta448]

my main question is why is my A/F ratio at 18:1 while driving?

I'm going to take a wild guess and say that this is only happening after you've completely lifted off the throttle at moderate rpm and are coasting.

The ECU will shut the injectors off on closed throttle deceleration on most relatively modern vehicles to assist with engine braking. It only happens when you lift at higher rpm and the injectors will fire again once the engine reaches the coded lower rpm limit. That allows the engine to reach idle speed quickly without falling past it and stalling.

okay so i think my maf is setup incorrect, and that is the main issue here, at idle it's reading .42 airflow per rev when it should be .25 ish, also my tps sensors voltage changed so i need to fix that/

You're compounding your problem. Fix all the basic items and unknowns first. Make sure the ECU is seeing an accurate airflow from your MAF first and foremost.

 

[genegoesfast]

Let me ask the real dumb question no one else has yet. What device are you using to determine your AFR?

 

[bradselph]

Let me ask the real dumb question no one else has yet. What device are you using to determine your AFR?

That's actually the best question asked so far

 

[KeelesKustome]

My dsmlink.

And no the whole time it's showing 18:1,, it only moves when i hit boost. I have a stock hacked maf, and apparently i need to make adjustements for that, i was not aware of this untill i started to try and remedy this issue.

Back to dsmlink basics, get my maf setup correctly.

what should my dead time be set at with these injectors?

n/m 330 and a test drive and long idle will confirm this.

 

[delta448]

So we're not getting the 18:1 AFR from a wideband O2 sensor?

Install a good non-hacked MAS.

 

[genegoesfast]

Sounds like that reading is coming from AFRest, which if the global/basic setting are off, isn't going to show you an accurate value.

 

[KeelesKustome]

It's close enoguht to tell me somethings wrong, because it spitts like crazzy under full boost.
My hacked mas seems to be the culprit. I'm not getting a unhacked mas, give me a break all i need to do is adjust a few variables for it and walla, it should be ready for more tuning.

 

[delta448]

Hacked MAS = you can't trust the airflow readings it gives you. It may read high at idle and low at WOT and you won't have any idea since you aren't logging a wideband. You'll just end up mapping the sensor's output per airflow on your own with your tuning, that or you'll suffer a poor state of tune with that sensor. In the end, modifying a MAS for less restriction gives you more problems than benefits.

The point is, you can't tune a hacked MAS without at least a good wideband.

Until you, or the person you'll end up paying to tune it, have that data this problem is going to go nowhere.

 

[KeelesKustome]

It seems, people do it all the time so it can't be the end of the world. A wideband is in the future but not right now. I just found on ecmlink a base setup for a hacked maf so that should be a pretty good equalizer.

 

[gusu]

It seems, people do it all the time so it can't be the end of the world. A wideband is in the future but not right now. I just found on ecmlink a base setup for a hacked maf so that should be a pretty good equalizer.

It COULD help assuming that the air you are taking in is the same as the other hacked MAF. The problem lies with the fact that you aren't accurately measuring the air that is going in, no two MAF hacks are going to be the same either. There are many other problems with it as well.

I'd just get the unhacked MAF for cheap and make things so much easier for you. Plus you won't have missing patches of pubic hair from where you ran out of hair on your head to pull out.

 

[GSXSixteenG]

It seems, people do it all the time so it can't be the end of the world. A wideband is in the future but not right now. I just found on ecmlink a base setup for a hacked maf so that should be a pretty good equalizer.

I have a hacked 2g mas, and my MAFcomp settings are way different then the template. I tried to originally tune the way you are off AFRest and its just not accurate enough to trust. I would highly recommend getting a wbo2 and log with link before you go any farther.