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Old 09-24-2002, 02:04 AM   #1
RallyNavvie
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Question stock decel fuel cut-off

Where is it?

I've got mine set to 2500rpm but I never really thought about what this is set to on stock vehicles. And what do you others with aftermarket ECUs have your fuel cut-off set to?

~Garrett
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Old 09-24-2002, 09:57 AM   #2
8Complex

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I don't think that the car normally completely cuts fuel... I think it brings it way, WAY down, though. I have mine turned on as well, and set to 1300.

Problem with the decel fuel cut-off is that it's a little jerky if you're floating around 0% throttle (as if you're trying to gear brake just a little bit, instead of a lot).

I've run both ways, but I prefer mine to be on.

BTW, my current map is on my web site if you want to take a look at it. It's on the Current State page.
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Old 09-24-2002, 12:31 PM   #3
RallyNavvie
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'little jerky'? Man with a 2400 lb clutch it can be downright jarring if I'm not paying attention below the fuel cut-off mark. Once the car starts to jerk it then jerks my right foot which in turn jiggles the accelerator and it only gets worse unless I lift or push. I also get a little bit of an exhaust pop when it crosses decels past the cut-off as well as a little jerk to let you know it happened.

I'm used to driving it for now, but since cruise speeds are generally close to 2500rpm (like 55mph in 5th gear or 40-45mph in 4th gear) I may drop it down to 2200 or something just to keep my ride a little smoother.

Did you alter your throttle pump settings at all? I guess I'll have to check out your map again and see what you've got. I can get some pretty loud exhaust flashes with my settings so I may have to alter them slightly.

~Garrett
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Old 09-24-2002, 12:37 PM   #4
8Complex

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Yeah, I altered my throttle pump settings and also the dead-band level in the fuel setup.

I decellerate and get down to almost where my fuel decel cuttoff is at before I put the clutch in, hence it's so low. I actually tune around my driving.

BTW, still dealing with the IAC... think I may have fried one side of the circuit trying all those combos. Oops, time to call Haltech. *shrug*
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Old 09-24-2002, 12:41 PM   #5
HndaTch627
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the stock ecu always cuts fuel whent he throttle is closed and decelling, but it's weird cause it doesn't cut instantly, it takes about a second and then it cuts.

jeremy
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Old 09-24-2002, 01:59 PM   #6
8Complex

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Yeah, I would assume it does it gradually, and probably reengages it gradually. I've never actually been able to look at how the injector duty cycles are on a stock ECU during driving conditions.
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Old 09-24-2002, 07:47 PM   #7
Scoobie Steve
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hmmm, i cant get my decel to work. every time i enable it, it stalls after reving. Do you guys have your idle control valve hooked up to haltech? I am using my stock computer for idle.

8Complex i will be glad to give you my current map if you are willing to post it on your site. Maybe it will be of help to someone. My setup is using 55lb injectors running 12-15psi on stock 2.2l NON turbo block. I have about 5k on this map with no problems. It will soon be wideband tuned since i just got my wideband soldered up.

Last edited by Scoobie Steve; 09-24-2002 at 08:07 PM.
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Old 09-25-2002, 02:05 AM   #8
RallyNavvie
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Well decel with the cut off is faster than decel without the cut-off isn't it?

Anyway yes, I actually do have the Haltech controlling the idle control motor which is a Subaru 6-wire unit and it does work. It did take me a while to get it working when we started the project but it is working. I suppose you want proof of it?

8 are you gonna be up at LSPR next month? We could compare noted there, I'll just stuff the gf in the trunk or something

~G
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Old 09-25-2002, 09:57 AM   #9
8Complex

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Scooby Steeve - What is your decel cut off set to in the fuel setup menu? I should have my IAC working, but it doesn't. Still have to call Haltech on that one.

BTW, somewhere on my list is a site for all the maps... one of these days I'll have time again. :-/

Garrett - No LSPR for me. I've been far too discouraged to go to any US rallies, just because I've heard how they're treating spectators, etc. :-/
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Old 09-25-2002, 12:24 PM   #10
RallyNavvie
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Send the maps to me, I'll host 'em on my website if you like. Besides, I need a good excuse to go back in there and update a few things

Don't be jaded from rally events just because of spectating. Volunteer to crew for someone. If I'm not competing I'll likely be crewing again. And don't spectate the first few rallies you go to, volunteer to work them. You'll get to know the people who run the rally as well as learn where all the best places are to spectate from. That way when you come back as just a spectator people will know you and not hassle you about where you're supposed to stand. Or you could ask the big boss for a letter to get a press pass and be official press for the i-Club.

~Garrett
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Old 09-25-2002, 12:45 PM   #11
yebokmj
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Default 2.2L NA block?

Scoobie Steve
Your running 12- 15 psi on a stock 2.2L NA block? Have you had to do anything with head gaskets? Any problems what so ever? As you may know WAC/wayne at 9psi blew two headgaskets before o-ringing the heads. I ask because I am running 6 psi and want to raise the boost, waynes problems have scared me away from doing it till summer when I would have time to do a headgasket if it's needed. Do you have any pics or info of your setup?
Joshua
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Old 09-25-2002, 07:48 PM   #12
Scoobie Steve
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I have it set to 1500 rpm. I will try raising it a little tomorrow. What i did do since i couldnt get cut off to work is set the injector pulse width very low at high vaccuum. my car at idle pulls 27hg of vaccuum so at 28 and higher the pulse width is very low. I can see this on the air/fuel gauge when i let off gas pedal, it goes very lean. I am thinking this might be some of the problem with it stalling when fuel cut is enabled. its just too lean and wont recover.

yebokmj my car has been turbo for about 15k and i have not had a single problem. Everything was custom made in my garage. The first turbo i ran was a huge IHI from a GM turbo deisel truck. It had some CRAZY top end but spooled poorly and as you might know the 2.2l heads suck up high. So i put together a custom turbo. I used a .42 exhaust(from Saab) and .60 compressor(from turbo coupe) T3. This turbo works nice and hits hard around 2800 rpm. Head gaskets normally blow from extremly high combustion chamber pressure caused mostly by detonation! Dont let it knock. What do you plan to run for fuel management? My 55lb injectors run about 80% duty cycle at 13psi, 60 psi fuel pressure. Suby engines like alot of gas, make sure you can supply it! If you have everything in order crank up the boost, you will LOVE it. Oh ya its faster 40-80mph then my modded wrx by far. Only thing that sucks is i have to hit three gears before 60mph!!
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Old 09-25-2002, 09:15 PM   #13
yebokmj
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Default My setup

Right now I am just running the HKS AFR along with RS injectors vortech 4:1 and walboro 255. I am planning on doing management this coming summer. Its tough being a college student. What A/F ratio are you tuning for?
Thanks,
Joshua
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Old 09-26-2002, 01:47 AM   #14
8Complex

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Damn Scoobie Steve, that is some HIGH vacuum. I would say that your decel cut off is ok, but I'm thinking that this vacuum is just too high to idle right.

It sounds to me as if your throttle plate is sealing REAL well and your IAC isn't opening at all/not fast enough. Have you tried creating yourself a vacuum leak or two and seeing if it still stalls out? More then likely, if you are getting more air in there, it won't do it so harshly.
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Old 09-26-2002, 02:02 AM   #15
RallyNavvie
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Yeah, I only ever see tops of 22 in/Hg at idle, but generally about 20. I think there may be issues with your idle control valve like 8 said. Might there be some issues with the stock ECU controlling the idle while the Haltech does what it will to the engine?

~G
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Old 09-26-2002, 09:36 AM   #16
8Complex

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Well, I'd be more concerned with the throttle plate sealing too well. 28in/Hg is like 2in/Hg away from absolute vacuum (science experiment area). Try turning in your idle set screw a twist or two... it's pretty sensitive, just a warning.
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Old 09-26-2002, 11:55 PM   #17
Scoobie Steve
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Yes you guys are right, my crapy VDO gauge reads ~27hg but haltech MAP says ~23hg at 880rpm. i tried decel fuel cut again but still no luck, even played with maps a little. Setting it to a higher rpm helped slightly(1900) but still stalled. I am thinking it must be an issue with stock computer controlling idle.

yebokmj
I ran rs injectors with 6:1 fmu, SAFC and walboro pump before i went Haltech. I found max psi with this setup to be around 8-9psi, anything more and egt's went too high and fuel mixture went lean. I did tuning with narrow band O2 so i cant really say what A/F ratio i was running. But now i will be tuning for 12:1 under boost.
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Old 09-27-2002, 10:05 AM   #18
8Complex

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Scoobie Steve - Do you have the zero throttle map on, or no? I think I'm running with it off, but it could be helpful if you want to tune that transition to idle.
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