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Blitzkrieg
 
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Yikes! 17.4 Idle AFR's

Just got around too installing my wideband and was shocked at the AFR's low 17's. I assumed it was going too be rich.


It Idles decent then hiccups and when it does this the fuel relays "click".

Where should I start first?
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Old 09-21-2011, 03:37 PM
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I wouldn't be concerned about the idle. What is it doing under boost ?
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Old 09-21-2011, 03:50 PM
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Quote:
Originally Posted by 9dreizig View Post
I wouldn't be concerned about the idle. What is it doing under boost ?
Didn't go there yet, out of fear! Even though I've been driving just fine as is for the last 2 years.
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Old 09-21-2011, 04:01 PM
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Well, if it is greater than 14.7:1 (assuming pure gasoline) the temperatures go down, lean of peak. That's what all the hot pilots try to do.

More than the stoichiometric air/fuel ratio for your fuel will be cooler. You just want to make sure the car is not in the hot range at high rpm / load.
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Old 09-21-2011, 04:06 PM
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Ok, this may shed some more light. Un-hooking My WUR makes no change at idle. No voltage at WUR with key on.
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Last edited by jly535; 09-21-2011 at 04:20 PM..
Old 09-21-2011, 04:15 PM
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Where is the sensor mounted?
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Old 09-21-2011, 04:49 PM
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Quote:
Originally Posted by jly535 View Post
Ok, this may shed some more light. Un-hooking My WUR makes no change at idle. No voltage at WUR with key on.
you won't have any voltage unless you're running (it's tied to the starter circuit).
voltage won't matter after the engine is warm,, only has to do with the cold start circuit and warm up element in the WUR
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Old 09-21-2011, 04:55 PM
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So fatten the idle up to 14/1 and go look at your cruise afr. You could also look at boost afr but don't go over 5000 rpm.
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Old 09-21-2011, 05:03 PM
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Quote:
Where is the sensor mounted?
About 18" after turbo.

Quote:
you won't have any voltage unless you're running (it's tied to the starter circuit).
voltage won't matter after the engine is warm,, only has to do with the cold start circuit and warm up element in the WUR
Got it, thanks.

Quote:
So fatten the idle up to 14/1 and go look at your cruise afr. You could also look at boost afr but don't go over 5000 rpm.
Thanks, searching this as we speak. Assuming this is just an allen wrech adjustment on the fuel head?
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Old 09-21-2011, 05:15 PM
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Quote:
Originally Posted by jly535 View Post
About 18" after turbo. Thanks, searching this as we speak. Assuming this is just an allen wrech adjustment on the fuel head?
Yes, simple adjustment on the mixture screw with an allen (6mm, or is it 4mm....whatever, you'll figure it out). Push down the adjustment plunger until you feel resistance while turning it. Clockwise to enrichen, but don't turn it more than a couple degrees at a time.

Your wide band sensor - mounted 18 degrees from the turbo - must be in the muffler tailpipe, correct? If it's too close to the end of the pipe, you will see an erroneous lean mixture 'cause it's seeing ambient air. If that's not your location, then a simple mixture adjustment will do you just fine.

This thing about your "hicckups" at idle, and hearing the fuel pump relays click. Damn, you can actually hear those things? They should not be clicking randomly. That's weird. More descriptions, please.
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Old 09-21-2011, 06:03 PM
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its 3mm, gotta press it down to engage the adjustment. remove air filter to have easier access, and you dont need much to get results

if the relay is clicking you have intermittent connection, should be no clicking. might be time for the fuel pump fuse rewire and fresh relays
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Last edited by slyguy; 09-21-2011 at 07:04 PM..
Old 09-21-2011, 07:00 PM
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Quote:
Originally Posted by mark houghton View Post
Yes, simple adjustment on the mixture screw with an allen (6mm, or is it 4mm....whatever, you'll figure it out). Push down the adjustment plunger until you feel resistance while turning it. Clockwise to enrichen, but don't turn it more than a couple degrees at a time.

Your wide band sensor - mounted 18 degrees from the turbo - must be in the muffler tailpipe, correct? If it's too close to the end of the pipe, you will see an erroneous lean mixture 'cause it's seeing ambient air. If that's not your location, then a simple mixture adjustment will do you just fine.

This thing about your "hicckups" at idle, and hearing the fuel pump relays click. Damn, you can actually hear those things? They should not be clicking randomly. That's weird. More descriptions, please.
Turbo, then about 18" muffler, then AFR Bung, then 8" pipe with turn down.

It was way lean, as soon as I richened it up it idle smooth like butter! I heard the relays clicking while standing there when it hicckuped. Basically it was too lean, hicckuped, then catched it's self.

Got it too 14.3 then went for a ride and it settled in at about 13.8 at idle. I will lean it out a little tomorrow.

Quote:
its 3mm, gotta press it down to engage the adjustment. remove air filter to have easier access, and you dont need much to get results

if the relay is clicking you have intermittent connection, should be no clicking. might be time for the fuel pump fuse rewire and fresh relays
Got'er little more tweaking tomorrow.

Thanks,

I'm actually having fun learning this thing. So many years with BMW's it's like starting over.
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Last edited by jly535; 09-21-2011 at 07:44 PM..
Old 09-21-2011, 07:36 PM
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my 2-cents: it's too close to your pipe exit... your low idle is allowing for some back-flow of fresh air to be mixed in at your 8" point...

when I moved mine to right after the turbo, I saw all that idle nonsense go away...
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Old 09-22-2011, 08:29 AM
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Aslo, if AIR injection is hooked up, you will get some false lean reads at idle.
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Old 09-22-2011, 08:33 AM
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Quote:
Originally Posted by gmendo View Post
Aslo, if AIR injection is hooked up, you will get some false lean reads at idle.
Gone.

Quote:
my 2-cents: it's too close to your pipe exit... your low idle is allowing for some back-flow of fresh air to be mixed in at your 8" point...
Based on installation instructions, it's too close too the turbo that way. I richened it up and it idles 100 times better. I will take the mixing into consideration when tweeking it a little more.
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Old 09-22-2011, 08:52 AM
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[QUOTE=mooney265;6268790]my 2-cents: it's too close to your pipe exit... your low idle is allowing for some back-flow of fresh air to be mixed in at your 8" point...QUOTE]

That's where I have mine located, with the bung welded to the muffler exit pipe so it's as far away from the end of the tailpipe as possible. Didn't want to risk frying the WB sensor if positioned directly after the turbo. My AFR's at idle are quite stable and maybe drop 0.2 points when increasing idle to say 2000, so I really don't think it's seeing much if any ambient air. But each setup/muffler/tailpipe combination would have their own unique challenges whether or not that location would work.
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Old 09-22-2011, 09:44 AM
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