Running too rich, what to do??

[Romogst]

I'm running a little too rich since i installed my new fuel pump, so, should i buy an SAFC or a fuel pressure regulator to lean it out to normal? Can i get my air/fuel ratio to normal number just with the SFAC?

 

[forcedfedgsx]

it depends on what size of pump you bought, an safc does control the air fuel mixture but if your over loading the stock regular with i high pressure 255 then you prob need a new after market regulator to bring the pressure down a bit

 

[hoffman]

what he said. til you get one, you could hack your MAS (NOT RECOMMENDED) to help lean things out alittle.

 

[Libila]

You tell him to do it then say you dont recommend it, funny. Running rich isnt all that bad, just wait until you can get a regulator and SAFC.

 

[Blk_99gst]

First off, why do you think you're running too rich? And don't tell me a blinky air fuel meter! Unless you have a valid gauge like an EGT or a pocketlogger, or unless you are spewing gas out your exhaust, then I question why you think you are too rich.

Yes, some bigger fuel pumps like the high pressure walbro can overrun the stock fuel pressure regulator at idle, and can cause you to run very rich at idle, rough idle, or gas leaking out the exhaust. Most other time/driving the fpr and the walbro get along just fine.

To find out if your fuel pressure regulator is getting overrun at idle, you need to messure your fuel pressure in psi at idle. If you do have excessively high fuel pressure at idle, then you will need and adjustable fuel pressure regulator to correct that problem.

A safc is meant to control bigger fuel injectors; not to correct a fuel pump overruning a stock fuel pressure regulator. And also hacking the maf to try to compensate is not even an option; that's just plain wrong. That's not dealing with the problem at all, and would probably create more problems.

 

[Tallen]

gimmie a shout and we'll do some datalogs (i'm around ravenna)...but yea on a 255 you prolly are running too rich.

http://www.roadraceengineering.com/eclipsetech/2gmasadjustment.htm
theres a big fat screw on the bottom of your MAF that you could screw out to lean about .01v. other than that, you could pull out the lower comb and ghetto tune it with the MAS screw till you get a good fuel computer (safc or translator) and a FPR.

idle will suck, so get ready to tweek the BISS too. aint it fun?

 

[Romogst]

I have the Walbro 255LPH high pressure fuel pump, i recently dynoed my car and the air/fuel mixture was 17.5 so the guy told me that that number is very high, i need to bring it a little bit down, i'm not sure what number is good for the dsm. I also have an EGT and tell me that i'm running rich. I think the best thing is to get the Fuel pressure regulator. right?

 

[TurboTerror]

17.5:1 is lean man. That is where stuff starts going VERY wrong.

 

[beeztsi]

if you bought a high pressure then yes you will need a afpr, you are over running your injectors

 

[ChicagoGSX]

If you ran 17.5:1 at full throttle on the dyno then you wouldn't have a running engine.

 

[TurboTerror]

Originally posted by ChicagoGSX
If you ran 17.5:1 at full throttle on the dyno then you wouldn't have a running engine.

correct

 

[Black95TSIawd]

i'm on stock fuel system with 2 shot o2 sensors and i'm blowing out flames.

 

[jpolizo]

Originally posted by Black95TSIawd
i'm on stock fuel system with 2 shot o2 sensors and i'm blowing out flames.

Cool!

I've been trying to figure out how to get that effect. Where's my diagonal cutters .....

 

[TurboTerror]

well, replace the sensors and fix your problem before it gets even worse.

 

[Black95TSIawd]

my car backfires. If i'm tearin up the streets running high rpms for a while....when i get off the gas and as the motor decelerrates it will blow out some flames

 

[ChicagoGSX]

Originally posted by Black95TSIawd
my car backfires. If i'm tearin up the streets running high rpms for a while....when i get off the gas and as the motor decelerrates it will blow out some flames

Running rich is not good, thats not something to be proud of. BTW the rear O2 sensor does not affect fuel so there is no need to replace it to fix your problem.

 

[TurboTerror]

He's right, running rich causes more problems than you think. You will foul out plugs like crazy. Your O2 sensors will become clogger, your cat(if you have one) will also clog up and block the exhaust like crazy. You better plan on tons of deposits building up in the entire intake tract, and most of the seals will start to deteriorate faster than normal. You might want to fork over the money and get your problem fixed as soon as you can.

 

[Kevin Jewer]

Everyone is quick to say the 255 is fine, or the 255 low pressure is fine, etc. Just a few points. One is that the difference between the high pressure and regular 255 at idle is almost nothing. It outflows the regular at high pressure, hence its name. I also have seen cars with 190s experience fuel pressure creep. Including mine. Its small, but its there. My base pressure with the hose ON is 43 On some cars this is due to the return line being restrictive, on other cars you'll find that isnt the cause. Either way I think its safe to say any car with a 255 of either type, rewired or not, is overrunning the FPR 99% of the time. Some people will tell you that thier car runs fine with it, but to them that just means it runs, and they may not even have a pressure guage or even a logger to properly diagnose the issue. Just a heads up. And as always, YMMV Always test and verify things for yourself, dont rely on what works for others or simply doing what other people say works. Hope that helps.

 

[Romogst]

Originally posted by ChicagoGSX
If you ran 17.5:1 at full throttle on the dyno then you wouldn't have a running engine.

ChicagoGSX, Listen man, the guy at the dyno knew what he was talking about he told me that number i got for my car is too rich, he had the sensor hooked up at the end of my exhaust. Everyone is saying this and that and running rich is not bad, running lean is bad.

 

[Blk_99gst]

Originally posted by Romogst


ChicagoGSX, Listen man, the guy at the dyno knew what he was talking about he told me that number i got for my car is too rich, he had the sensor hooked up at the end of my exhaust. Everyone is saying this and that and running rich is not bad, running lean is bad.

Some definitions:

Running safe rich - Just a tad on the rich side, extra margin of safety for the motor. Running here is good

Running shooting flames out the exhaust rich - Not good for reasons described above. Spark plugs get fouled, o2 sensor's get fouled, gas milage is in the single digits.

Runing lean - Also bad for the engine; will cause internal parts to melt.

Maybe you mis-understood the guy and instead of 17.5:1, maybe he said 7.5:1; that would be shooting flames out the exhaust rich. Ideal air fuel ratio for a turboed car is around 11.5:1, with 12:1 being leaner and 10.5:1 being richer.

 

[candela]

ChicagoGSX, Listen man, the guy at the dyno knew what he was talking about he told me that number i got for my car is too rich, he had the sensor hooked up at the end of my exhaust. Everyone is saying this and that and running rich is not bad, running lean is bad.

LMFAO... dude these guy sare giving you good info here. Im not going to elborate, but if that guy said the you have an A/F ratio on 17.5:1 and you are running "rich" then you need to go to a new shop simply for the sake of your poor little 4G63's life If you were running the A/F ratio on a WOT run (in boost) your engine simply would NOT last....
Get a FPR, settle down, go to a new shop and then dont worry about your car so much cause either he is blowing smoke up yoru ass, something is seriously wrong with his gauge or he is lying to get you back in his shop or something. Your car has a catback for mods...thats really not to serious if you know what I mean, so as long as all your injectors are firing dont worry about it


Austin

 

[Romogst]

The guy from the dyno place gave me a print out of my run and on it, was Max AIR/FUEL = 17.5 that's all, i'm assuming that number is too high, like he said that is way too rich and i need it to bring it down some. No flames or smoke coming out of my exhaust, car runs good.

 

[Black95TSIawd]

i never intended to brag about my flames. I personally dont like it. I want my car to last. Also, when i'm at idle lets say at a red light, i can smell the fumes in the air. Granted i have a straight pipe but it still stinks bad.

And what i really need is just the front O2 sensor but i will replace both and keep the second tucked somewhere underneath the car so i can get rid of that pesky CEL.

 

[andol469]

Originally posted by Romogst
The guy from the dyno place gave me a print out of my run and on it, was Max AIR/FUEL = 17.5 that's all, i'm assuming that number is too high, like he said that is way too rich and i need it to bring it down some. No flames or smoke coming out of my exhaust, car runs good.

Yes, a 17.5 A/F ratio is too high. It's too high because it's LEAN. Think about the numbers man, the ratio of air/fuel. Higher numerator means leaner, lower numerator means richer. Just think about it. If it's at 17.5, that's way too lean.

 

[Gen2Eclipse]

Just get a new FPR, or some 550's and problem solved.