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Old 04-24-2001, 10:33 AM   #1
Scoober01
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Post Controlling the fuel system Why-how-when.

I know a few people on the board that could benefit from this post. With a lot of the mods we all do here i.e.; CAI, high flow filter, and all different types of exhaust, our cars may be running lean or rich at different RPMs. Some may not even know that its going on. This can be potentially damaging to the engine and your not getting your full performance.

Right now I think I'm running lean up top. I know a few people that are running rich and getting black soot on their exhaust and back firing all over.
So What we need is some suggestions on how to make a determination if we are running lean or rich and then how to remedy the issue.

I have done some searching and did come up with a lot of good info.
As far as I can tell from what I found, the best tool for monitoring lean and rich conditions is a EGT gauge(exhaust gas temp).
I found the best temp to go for at WOT N/A is 1400 , From what I gather if your getting around 1350 your rich and if your getting 1400+ your lean, Correct?

Okay so now that we have determined the condition, how do we correct it for a N/A application.
I think I understand how a RRFPR (rising rate fuel pressure regulator) works. It's mainly for turboed cars and will adjust the fuel pressure when under boos only. For every 1psi of boost it will raise the fuel psi by 5, 5:1 correct. For N/A this is no help, though I heard you can use a RRFPR on a N/A setup as a FPR (fuel pressure regulator) and just set a psi. That brings me to my next question. The stock fuel PSI is set to about 30psi if we set it to say 40psi to correct for lean conditions around 4000-6000 rpm will this not in turn create rich conditions at lower RPMS.
If I get just a high flow fuel pump will the stock ECU be able to take advantage of it correctly?

So on a MY00-01 that can't use a S-AFC what can we do to really be able to control the fuel system through the entire RPM range?
any info would be great.
Ryan D.



[This message has been edited by Scoober01 (edited April 24, 2001).]
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Old 04-24-2001, 10:50 AM   #2
tmat3
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Why can't MY00/01 use SAFC? I use it on my MY01 and works good. It runs rich at high RPM and throttle, so I just decrease a fuel amount a little.

You are correct about the EGT. 1400 should be the correct temp. Anything less is rich and anything over is lean.
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Old 04-24-2001, 11:03 AM   #3
Scoober01
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I've been told by many people that the S-AFC is useless on a MY00-01 because the ECU will slowly correct for the AFCs setting so it will be at what the ECU wants and not what the AFC is set at. If I'm wrong someone please correct me.
Ryan D.
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Old 04-24-2001, 11:05 AM   #4
tmat3
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It's true during normal cruising, but not when high throttle / RPM.

In a way, it is true -> it's useless and less needed than MY99 or 98 because the ECU can learn eventually. But, you can still lean out at higher RPM and throttle.
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Old 04-24-2001, 11:13 AM   #5
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have you asked jcs? they are right there ya know..
Brian
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Old 04-24-2001, 11:21 AM   #6
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Because of the 4.8v MAP sensor voltage limitation, you can't use an S-AFC to enrich a boosted MY 00-01. And in N/A conditions it won't enrich when the MAP voltage is at maximum.

However, you can use it to lean out a rich boosted MY00-01, because you are subtracting voltage.
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Old 04-24-2001, 11:25 AM   #7
Scoober01
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Thanxs for the info, but no real help there. I'm looking for some suggestions, I don't really want do get in to a argument about the S-AFC. ***I can't use one***.
So other than a S-AFC what might I be able to use.


[This message has been edited by Scoober01 (edited April 24, 2001).]
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Old 04-24-2001, 01:02 PM   #8
Keiho
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Get a fuel computer. That's basically it, Apex'i SAFC or Field Hyper R. I'm not sure about the Apex'i unit, but the Field one works on mine. Dynochart to prove it too.

Or if you're really that worried, get a full standalone ecu like Tec-II, Haltech, etc. That will solve all your tuning woes.
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Old 04-24-2001, 01:53 PM   #9
Scoober01
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OOOoo no, I feel my tuning woes have just started. I really don't want a S-AFC or tec-II, well I like the tec but I don't have the money or time I would need to spend with it.
Maybe I need to just talk to Larry.
I had his # but lost it, anyone have it?

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Old 04-24-2001, 03:07 PM   #10
Scoober01
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You guys really don't wanna give up any info do you. I would really like some help, please. pretty please. Anyone, PLEASE.
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Old 04-24-2001, 04:28 PM   #11
Keiho
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I thought I answered your question?

You want to tune your fueling issues after determining the problem with the gauges/probes, etc?

Read what I posted! Apex'i SAFC, Field Hyper R, etc.

Geez...

You want proof it works? Look at my member pics, I've got a dynochart in there showing how much gains I got after tuning the Hyper R.
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Old 04-24-2001, 06:15 PM   #12
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hmm...you could do a fuel pressure riser (not raising rate) and a fuel pump, but besides that you're pretty much limited to a computer device
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Old 04-25-2001, 12:55 AM   #13
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Please people, just a little help I'm not asking that much.

Ryan D.
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Old 04-25-2001, 03:09 PM   #14
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This is specific to the MY00+ with MAP sensors.

The S-AFC will work on a NA car to enrishen, only to the 4.8V limit of the MAP sensor signal going to the ECU, then you get a fuel cut. Also, too much leaning out with the S-AFC will result in a CE light for "low manifold absolute pressure".

Better is to get a JC Sports Torque Chip and a fuel pressure regulator set for about 40-45 psi fuel pressure, and/or a high flow fuel pump with that. Note, too much fuel pressure while cruising steady throttle will result in a CE light for "catalyst efficiency below threshhold".

Hope this helps,

Larry
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Old 04-25-2001, 03:25 PM   #15
Scoober01
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Okay Larry just put all of you to shame, J/K I appreciate any help I can get.

Just to update, with the info I've gathered from all over this is what I'm doing.

-stock gauge housing
-EGT Gauge
-A/F gauge
-Oil Temp/Pressure combo.
-FPR--set to 40/PSI
then
-TCII-from JC--later, much later.

From what I'm told by Larry, if just the PSI is raised by a FPR and no S-AFC or Hyper-R is being used the stock ECU will learn to turn down the injectors at lower throttle settings. So I won't need to worry about being to rich in the lower RPMs. Question answered.
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