2g mas in a 1g issues..

[bme91gsx]

did some searching and i am just confusing myself.. first off heres the list of mods..


Evo III 16g Turbo 18 psi
2g Exhaust Manifold
3" Apexi N1 Down Pipe
34mm Flapper
Ported o2 Housing
ARP Headstuds
HKS metal head gasket
Apexi SAFC
Palm iiic Datalogger
A/F Gauge
Boost Gauge

now i just installed the 2g mas.. i still have the 450cc injectors.. i took the car out on the highway and it seems to be running a lot richer than before.. so i adjusted the safc and got it running a little better.. my idle isnt as smooth as it used to be... but it seems to pull harder.. no knock or anything.. something just doesnt seem right with it though.. from what i understand i should be running 550's but i cant afford them right now. seems that when people install this they should be running leaner not richer so i am confused.. has anyone ran a 2g mas with 450's and similar mods? any info or advice is greatly appriciated

Thank You..

 

[toofast82]

As long as you have an SAFC, you should be able to compensate assuming you have a logger. I always recommend a wideband for any tuning as well. It makes things so much easier, accurate, and safe!
I believe the 2G mas reads like 20% more air

 

[Colt4G63 also]

It's not normal for it to be richer. The 2g MAF will read about 1400Hz with the same flow volume that a 1G would be over running at 2000Hz. The ECU would think it's getting less air, so it would provide less fuel, therefore it would run lean.

 

[bme91gsx]

exactly this is why i am lost..and yes i have a logger and my fuel trims did not budge the whole time i was out about a 20 min ride on the highway..

 

[Colt4G63 also]

Niether one is hacked? Check for a boost leak, I think I remember you forgetting to tighten something.

 

[toofast82]

"Seems" to be running richer and "IS" is two different things! Wideband takes care of this guesswork
If you have no boost or vacuum leaks and everything is all good, you should have to add roughly 15- 20% to compensate. What are your fuel trims?
Honeycombs are intact and screw is unadjusted?

 

[bme91gsx]

ok.. it is running richer.. for instance at first going down the highway o2 trim was bouncing from 50-70%i adjusted the afc and @3k rpm it was going from 90-110%.. the fuel trims never changed.. low 91.4 med 96.7 high 100.7.. the middle honeycomb is gone.. and im not sure what you mean by screw.. i dont think i have a boost leak or anything the boost guage holds steady at 18 psi... ive been looking into my 255 w/o a regulator and thinking this may be why... the 1g maf i had in there was hacked..

 

[bme91gsx]

thanks for the replies btw..

 

[toofast82]

If the middle screen is out, the ecu read less airflow on the low end.

These may help for low end tuning:
Apexi Super AFC For The Eclipse/EVO
RRE's Super AFC Setting and Adjustment Tips
http://www.dsmtuners.com/forums/frequently-answered-dsm-questions/111005-basics-tuning.html
How much time are you giving the ecu to adjust trims when you adjust something?
Just need to get the low and mid sorted and you should be good!

 

[rush2252]

It's not normal for it to be richer. The 2g MAF will read about 1400Hz with the same flow volume that a 1G would be over running at 2000Hz. The ECU would think it's getting less air, so it would provide less fuel, therefore it would run lean.

The 2g MAF will make a 1g run RICHER. This is backwards... I have a friend who has a 2g on a 1g car with the 450s and the car ran like shit. We put the 1g back on and it ran ALOT better.

 

[bme91gsx]

thanks guys

 

[habitatguy187]

The 2g MAF will make a 1g run RICHER. This is backwards... I have a friend who has a 2g on a 1g car with the 450s and the car ran like shit. We put the 1g back on and it ran ALOT better.

No the 2g mas will make a 1g car run leaner. The 2g mas allows more airflow but reads aprox. 20% lower than a 1g mas in hertz measurements. Which is why the common thing to do is add 550s when upgrading to a 2g mas. The mas sends a lower air signal to the ecu, causing the ecu to send less fuel, but since the 550s provide more fuel at a lower injector pulse width it about evens itself out.

As a sidenote though, I have a 2g mas and 550s but my fuel trims are all maxed out at 81.2%, saying that I'm running way too rich also, but my gas mileage is around 24mpg (get on it quite often) and I never see any black smoke or smell gas, so I really need a wideband to tell what's really going on.

 

[JayRolla]

To the OP how do you know you are rich at WOT. Do you see smoke? You cant trust you A/F guage because it works off the narrow band o2. Its pretty much a waste of money and for show. Its pretty much impossible for you to put that 2g maf in and be running rich. You need to get a wbo2 before you burn up a valve.

 

[bme91gsx]

i was going off o2 voltage.. for now i am going to put the 1g back in and get some 550's