SaabGuy

Im using 2 injectors from a gslse vehicle. They are posted on this forum as being 680cc but the company who cleaned them for me swore that they are Nippondenso 760cc. Anyways thats not my problem. The problem is Im running wicked rich at wierd rpms.

I have already turned my safc way down. When I first started this yesterday my car would painfully rev past 4 grand. Now the tuning seems to be pretty good on top, but right in the middle is where it gets hairy.

My testing/tuning has consisted of a normal a/f guage and the the way the car feels. I have noticed a lot of bucking and poping out the tail. its running really rich. What I am working on for tuning is this: Cruise in 4th gear at a specified rpm, lift the ebrake and keep pressing the gas pedel. This allows me to floor the car and remain at a specified rpm for tuning. When I do this at 3000 rpms my car bucks fairly after about 50% throttle.

I am affraid of lowering the settings any more on my safc. at 3000 I am already at -15%, 3500 -17% 4000 -21% 8000 -21%. When I didnt have the 680cc my settings were 3000 -3% 4000 -5% 8000 -10% and this was dyno tuned.

How freaking lean do I have to go? and why are the secondaries firing at 3000 rpm? Does the computer depend on airflow percentage and/or 3800 rpms?? Its bizaar.

Ryde _Or_Die

What mods do you have? I was having the same trouble and it went away by adding fuel. I kept taking more and more away, but it never helped till I added some or actually went just about at 0 most everywhere. I am running like 7.5lbs pretty solidly.

SaabGuy

If I add fuel the problem gets worse. When I lean it out on the safc the problem gets less and less, but the settings are getting very low.

Mods:
87t2
RB turbo back
stock intake stock filter
fcd
s5 turbo with upgraded compressor (slightly) running 6psi
walbro rewired running 14.4v constant (no switching)

My safc claims about a maximum of 75% airflow.

1FastT2

iTrader: (1)

Your cars turbo right? How much boost are you running when you are going though your testing?

Turblown

iTrader: (12)

i thought the s-afc couldn't control anything more than 720's, so if they are really 760s maybe thats ur problem.

Ryde _Or_Die

I really don't know what to tell you. I'd be afraid without even an egt gauge to take out too much fuel. Might be worth the money to get it on a dyno. Better to be safe than sorry.

SaabGuy

To give a better idea of the amount of power being pushed, I had the car dynoed at 203 rwhp about 5 months ago with the mods listed above.

1FastT2

iTrader: (1)

I have never heard of that but you do have a point. Maybe its something else besides the fuel that your having prolbems with.

Ryde _Or_Die

Ya thats very true. Who sold the injectors to you? When they cleaned them, did they blueprint them as well? I mean if they did, and told you what they flow, then thats what they flow and probably what actual injectors they are. What happens with the wrong impedence injectors?

SaabGuy

The bucking at 3000 rpms happens when I am at about 4psi and a bit over half throttle.

Just to let you know I rewired the safc's tps setting to get an actual setting based on foot level. Non of this 100% crap when the trottle is tapped.

SaabGuy

I bought the injectors from someone out west. I brought 2x550cc and 2x680cc to a local place (www.injector.com) and had them cleaned and blueprinted. I've got the papers. All injectors are fine, my 550's were really dirty. The injectors are functioning properly. The guy put a scope to the coil and did a number of tests. He was good enough to tell me that 680cc gslse injectors were actually 760cc (at 42psi).

1FastT2

iTrader: (1)

It quite possibly could be just the injectors coming online. What I would do is try to compensate with the AFC and put a little dip in the graph at 3000rpms and then gradually increase the fuel.

SaabGuy

I really cannot tell how the test was done. Looks like the guy pulsed the injectors with 6milisecond bursts at like a static pressure of 42psi. The 550'c flowed 180cc and the 760's flowed 240cc. It was a pulsing test of some sort.

SaabGuy

I am already dipping about 15%. Im just affraid of dipping lower. Dammit I need a wide band o2!

Ryde _Or_Die

Try raising it at 3k and then lowering it at 4000. Might be able to smooth out the transition when the secondaries come on.

kep0ne

maybe you should just fork out the cash and get it dyno tuned...it would only help

NZConvertible

The 84 GLS-SE injectors are "officially" 680cc/min and the 85 GLS-SE ones are 720cc/min, but the actual flow depends on the test pressure used. When comparing them to the stock 550cc/min injectors just think of them as 720's, because Mazda's figured are probably based on the same test pressure. You probably have the 720's. You should really do this on a dyno with a wide-band A/F meter. The stock O2 sensor is incapable of telling the difference between rich and really rich. Try to find a long steep hill instead. It'll be a lot easier on those poor rear brakes! You have to realise exactly how much bigger these injectors are. The 550's only flow 76% what the 720's do, so you need to apply a -24% correction (100% - 24% = 76%) just to get them to behave like the stock injectors. Then you'll want to lean it out a bit more to maximise power. Also, if you're using stock primary injectors, you shouldn't be touching the below-3800rpm settings at all! -15% at 3000rpm and -17% at 3500rpm will be far too lean.

I really think you should go to a dyno and have it tuned by someone with some experience with the S-AFC.

Scott 89t2

ya as above there is no need to change the settings under 4000rpm. the bigger injectors arn't even on yet... put the 3000 one back to -5 or where ever you had it. if it still has problems. it's something else. maybe you put the injector wires backwards or something...

and stop doing it the way you are... set it all to 0. it should run just fine like that, just not as fast as when tuned. then you must get some wide band tunning done.

SaabGuy

Somthing is definatly wierd with my car. Since I rewired my fuel pump to a constant 14v the car idles rough unless I put the settings at 1000 rpm down to -13%. I'll look into it more tomarrow though.

And yes I put the larger injectors in the secondary fuel rail. Wired everything correctly as well. Im not an idiot. low to mid throttle openings are fine below 4k. its when I go past 1/2 throttle I have problems.

SaabGuy

OK I just took my car for another series of tests.

I set the safc to the following;
2000 -3%
3000 +5%
3500 +5%
4000 -16%

The car bucks extremely bad within the 3000-3500 vicinity on these settings. So then I changed the settings to;

2000 -5%
3000 -13%
3500 -14%
4000 -16%

and the bucking almost went away. A/F guage reading full rich with either of the above settings.

*I know people dont like giving safc settings out due to people being stupid, I just want to know if my settings seem at all acurate. The more fuel I give at 3 and 3.5k the worse the bucking gets.

OPEC

SaabGuy.. Here are my settings and for me they work quite well. But every car is different.

Here are my SAFC settings.. I have 4x720cc injectors, walbor, older HKS front mount, unported motor, stock turbo running 11-12 psi, full 3" exhaust. I have dyno'ed with close to these settings and then have done minor tuning and fine adjustments on the street with my FJO wideband.

Low Throttle 20% High Throttle 60%

HI
1k 0
2k +2
3K +2
4k +1
5K -8
6K -14
7K -20
8K -14

LO
1k -5
2K +5
3K +5
4k +5
5k +2
6k +2
7K +2
8K +2

For me these are pretty safe settings, never really ever see over 11.0 on the wideband and the EGT's are nice. I could lean out the low settings some, but with out being able to control when the secondaries come on, I was going a tad lean before 4K so I have it set a bit rich to make up for it till secondaries come on. Hope this helps a little.. But again, no car is alike.

SaabGuy

Nevermind I ******* put the larger injectors into the primary rail.

I love to beat my head against the wall because it feels so good when I stop.

The secondary fuel rail is the longer one right???? I put the injectors into the shorter one.

NZConvertible

Dude, you messed up big! Yep, the primaries go on top of the center plate and have a short rail, the secondaries are mounted higher up on the manifold with a long rail. Oops..

Take them out and swap them around. Then set your below-3800rpm settings at zero and your above-3800rpm settings at -24%. This should make the car run like stock. Then head to a dyno and have it tuned to maximise power.

Turblown

iTrader: (12)

well atleast you got it figured out.

SaabGuy

AAAAAAAAHHHHHHHHHHHHHHHHHHHH )

Its soo much better now!! Hardely any tuning when they are in the secondaries!! I can tell stuff is way richer though.