Lean idle = leaking headers?
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From: Mannheim, Germany
Lean idle = leaking headers? My fuel trims are maxed out at 25+% to get my A/F at 14.7 while idling.
If I reset the FT's with BIDI, the I get these reading for a second until the FT's kick in again.
WBO2 showed 19:1
O211 showed .100v
O221 showed .060v
If I give it any amount of throttle, the LTFT's go to the normal range of badness like 10%.
Would leaking headers cause my O2's to only read lean (by that much) at idle?
BTW, I only have one WBO2 on the driver's side. Hmm I think I should install a bung in the passenger side this weekend and see if both sides behave the same.
When I reset the FT's, the stock sensors go .0X volts for a few seconds
If there's any other info that can help here, I logged quite a few parameters so I can post more or email a scan.
If I reset the FT's with BIDI, the I get these reading for a second until the FT's kick in again.
WBO2 showed 19:1
O211 showed .100v
O221 showed .060v
If I give it any amount of throttle, the LTFT's go to the normal range of badness like 10%.
Would leaking headers cause my O2's to only read lean (by that much) at idle?
BTW, I only have one WBO2 on the driver's side. Hmm I think I should install a bung in the passenger side this weekend and see if both sides behave the same.
When I reset the FT's, the stock sensors go .0X volts for a few seconds
If there's any other info that can help here, I logged quite a few parameters so I can post more or email a scan.
Last edited by kenkaru; Sep 1, 2006 at 03:01 PM.
Originally Posted by we_todd_did
Most cars will run lean on idle due to a rich condition is hard to idle.
The best way to spot leaky headers is to go WOT. You will see the two O2s lock up ~900mV, and if there's a leak, one of them is going to drop off toward lean territory.
Thread Starter
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From: Mannheim, Germany
Should have posted my sig.
Advertised Duration Int. : 279°
Advertised Duration Exh. : 287°
Camshaft Duration @ 0.050" I/E : 219°/228°
Camshaft Lift I/E : 0.525"/0.525"
Lobe Seperation Angle : 112°
RPM Range : 2200 - 6500
Does this look like a cam that would have the overlap to trick the O2's into reading lean?
I'm going to "seafoam" with some ATF and see if it's leaking too.
Thanks!
Advertised Duration Int. : 279°
Advertised Duration Exh. : 287°
Camshaft Duration @ 0.050" I/E : 219°/228°
Camshaft Lift I/E : 0.525"/0.525"
Lobe Seperation Angle : 112°
RPM Range : 2200 - 6500
Does this look like a cam that would have the overlap to trick the O2's into reading lean?
I'm going to "seafoam" with some ATF and see if it's leaking too.
Thanks!
On The Tree
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FWIW. That looks like the Hotcam.
I have the Hotcam and although I'm running a very different set-up and in SD I sorted my idle using the STFT and smelling for gas. It worked really well and I have a smooth idle at 750 rpm (1050 down to 750 from cold to hot).
I was surprised at the comparitively small VE values I ended up with at idle MAP in the 800 and 1000 rpm columns.
Tom.
I have the Hotcam and although I'm running a very different set-up and in SD I sorted my idle using the STFT and smelling for gas. It worked really well and I have a smooth idle at 750 rpm (1050 down to 750 from cold to hot).
I was surprised at the comparitively small VE values I ended up with at idle MAP in the 800 and 1000 rpm columns.
Tom.
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Thread Starter
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From: Mannheim, Germany
Originally Posted by Tommy Tucker
FWIW. That looks like the Hotcam.
I have the Hotcam and although I'm running a very different set-up and in SD I sorted my idle using the STFT and smelling for gas. It worked really well and I have a smooth idle at 750 rpm (1050 down to 750 from cold to hot).
I was surprised at the comparitively small VE values I ended up with at idle MAP in the 800 and 1000 rpm columns.
Tom.
I have the Hotcam and although I'm running a very different set-up and in SD I sorted my idle using the STFT and smelling for gas. It worked really well and I have a smooth idle at 750 rpm (1050 down to 750 from cold to hot).
I was surprised at the comparitively small VE values I ended up with at idle MAP in the 800 and 1000 rpm columns.
Tom.
I have EFI-L.
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Yep will do but it will have to be tomorrow as I'm now at work and my files are at home. As long as you understand that it's a 'tune in progress' 
and that I'm in SD.
My idle map is about 50KPa by the way.
The hotcam has enough overlap to generally fail idle emissions (hydrocarbons). So that means that a significant amount of the unburnt charge passes into the exhaust at idle.
and that I'm in SD.My idle map is about 50KPa by the way.
The hotcam has enough overlap to generally fail idle emissions (hydrocarbons). So that means that a significant amount of the unburnt charge passes into the exhaust at idle.
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From: Mannheim, Germany
Originally Posted by Tommy Tucker
Yep will do but it will have to be tomorrow as I'm now at work and my files are at home. As long as you understand that it's a 'tune in progress' and that I'm in SD.
My idle map is about 50KPa by the way.
and that I'm in SD.My idle map is about 50KPa by the way.
The hotcam has enough overlap to generally fail idle emissions (hydrocarbons). So that means that a significant amount of the unburnt charge passes into the exhaust at idle.
On The Tree
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That's what I inferred from what RedHardSupra was saying...and it makes sense. Because of the overlap you actually have less air in the cylinder at idle as some is being lost to the exhaust. So although the VE table will require enhancement off idle and in the mid and upper RPM areas, at idle range the VE will be lower than a similar cam with less lobe overlap.
My idle was very rich when I put the hotcam in on stock settings. Definitely had a strong gas smell.
My idle was very rich when I put the hotcam in on stock settings. Definitely had a strong gas smell.
Last edited by Tommy Tucker; Sep 6, 2006 at 05:40 AM.
Thread Starter
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From: Mannheim, Germany
Does SD use fuel trims?
It seems to me that no matter what I do, the O2's are always going to read lean at idle and add fuel.
This is good. I'm actually understanding everything in this conversation so far and your hotcam experience sounds similar to mine. I checked my MAP at idle and I'm right at 50 kpa's too.
I'll post up a pic of my VE when I get home just for whatever.
It seems to me that no matter what I do, the O2's are always going to read lean at idle and add fuel.
This is good. I'm actually understanding everything in this conversation so far and your hotcam experience sounds similar to mine. I checked my MAP at idle and I'm right at 50 kpa's too.
I'll post up a pic of my VE when I get home just for whatever.
Last edited by kenkaru; Sep 6, 2006 at 08:38 AM.
Thread Starter
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From: Mannheim, Germany
I adjusted my IAC steps to 60 today. Yay! It helped out a bit to make the car idle a little smoother and it doesn't surge as much. It's slowly getting there.
Bringing the steps from 30 to 60 also brought my desired and actual airflows within .2 Before, I was trying to get them closer but they would never get closer than about .8
Thanks! any luck on the image of your VE table? or if you'd rather email me an excell sheet, I can pm you my email.
Bringing the steps from 30 to 60 also brought my desired and actual airflows within .2 Before, I was trying to get them closer but they would never get closer than about .8
Thanks! any luck on the image of your VE table? or if you'd rather email me an excell sheet, I can pm you my email.
