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just ordered a colortune

$56. what the heck. might be interesting to see what the 930 shows.
I still have the very rich idle, about 11. might also be nice to see the balance after all the LM2 "averages" all 6 cylinders so if some are lean, the others may be rich. that is if I had a better idle AFR.

since the O2 measures oxygen, what makes it so oxygen depleted?

don't get me wrong, the car runs great, it just bothers me that it is so rich at idle.
idle is smooth, no hesitations, pulls good.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-21-2017, 04:21 AM
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Man, my eyes would be watering at 11AFR at idle.

The idle mixture screw doesn't do anything? Mine is super sensitive.

Let us know how it goes. It is a pretty neat tool for individual mixture tweaking. I guess you have to adjust it at the fuel head if you find they aren't balanced?
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Old 07-21-2017, 06:35 AM
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that's just it.
it does not act like a car that is that rich, never has,. it does not have the rich smell to it either.
its just the idle that's rich.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-21-2017, 10:53 AM
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Brando
 
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Mine was like that..........
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Turbo powa!
1977 911s. it's cool
Old 07-21-2017, 11:09 AM
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Crotchety Old Bastard
 
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Doubt that the idle is actually that rich, it would oscillate. Could just be a bad reading, where is the O2 sensor located?
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 07-21-2017, 06:16 PM
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Quote:
Originally Posted by T77911S View Post
don't get me wrong, the car runs great, it just bothers me that it is so rich at idle.
idle is smooth, no hesitations, pulls good.
If it aint broke....

What's bothering you is simply a number on a readout, if the car likes it where it's at, don't mess with it, just enjoy...
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Old 07-21-2017, 09:32 PM
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right now the O2 is before the turbo but I have also put it in the tail pipe and same thing.
things like this just bug me. I don't devote all my time to it since it does run good but I do mess with it every now and then,.
I am going to mount a bung in the zork and move it there.
I pout the bung pre turbo planning on measuring back pressure.

I had a 77s that would spark knock above about 3500 or if you floored it.
drove it like that for several years, working on it off and on.
I found the PO had advanced the cam timing 15 degrees, that improved the problem, then I eventually found one of the plastic fuel lines was defective and restricting the fuel flow. after that the car ran incredible.
learned a LOT about the car, especially CIS.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-24-2017, 03:25 AM
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Crotchety Old Bastard
 
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I know that you are familiar with CIS, which helps considerably when the odd issues arise. I've seen this "ghost" low AFR at idle on 930's before and had it on one of mine as well. I've never dialed into what exactly causes that phenomenon but do know that it is not a true representation and seemingly caused no harm. If you take away the gages and tune by ear then hook up the gages you can see some of these oddities. That is when I check my gages.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 07-24-2017, 03:50 AM
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yea. use to tune my 77s by ear. then got the LM and checked it and it was dead on what it should be.
the 930 is harder to tune. I have always thought due to the lower CR. also the 930 is more critical at hi RPM than the 77s.

if anyone drove my car they would never suspect the "rich idle"
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-24-2017, 05:37 AM
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All the idle AFRs are different. Every engine has a different sweet spot. Then throw in changes like cams, headers etc. I do mine by ear irrespective of the AFR. The older (wear) the engine, the richer they like it. If the engine is running sweetly at 11 on idle, then I would live with that. I have read plenty of posts where guys are tuned to around 13+ on idle. Mine goes very lumpy/grumpy at 13 and is much happier around 12.
Regards
Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 07-24-2017, 12:54 PM
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Thing is; rich is rich, and 11:1 is drowning in gas rich. This is why it has to be an anomaly reading. The idle should oscillate at that level. I also set the idle by ear then check the AFR as a reference. Idle mixture directly affects the entire operating range so if the mixture is 14.5:1 at cruise it is unlikely to actually be 11:1 at idle. The typical range I see is 12:1 on the low end and 13.5:1 on the high end. Either way the engine does have a sweet spot at idle and that is where it should be set.
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'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
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Old 07-24-2017, 04:39 PM
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If you rev the motor up from idle quickly or "blip" the throttle the rpms will drop down a little below the regular idle speed for a second or two and then come back up to regular idle speed if it's running too rich.

It may also oscillate up and down at idle speed like Brian said. That's probably a negative side effect of the slow response time of mechanical air flow meter controlled fuel injection when it's running too rich at idle. Advancing the idle ignition timing can help clear up some of the running too rich at idle oscillation stuff if it does that.

When I had one it idled smoothest around 12.8:1 AFR and up to around 13.5 was fine too but 12.8 to 12.9 was the best with todays E10 93 octane unleaded gas.

Some of the problem is because of the ~E10 premium unleaded pump gas we get these days. Years ago gasoline had no ethanol in it.

Ethanol has oxygen molecules in it if that's the right word for it so the higher the percentage of ethanol to gasoline you're burning the richer the AFR mixture has to be because of the oxygen in the ethanol.. for it to run right.
Old 07-24-2017, 05:40 PM
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Quote:
Originally Posted by JFairman View Post
If you rev the motor up from idle quickly or "blip" the throttle the rpms will drop down a little below the regular idle speed for a second or two and then come back up to regular idle speed if it's running too rich.

It may also oscillate up and down at idle speed like Brian said. That's probably a negative side effect of the slow response time of mechanical air flow meter controlled fuel injection when it's running too rich at idle. Advancing the idle ignition timing can help clear up some of the running too rich at idle oscillation stuff if it does that.

When I had one it idled smoothest around 12.8:1 AFR and up to around 13.5 was fine too but 12.8 to 12.9 was the best with todays E10 93 octane unleaded gas.

Some of the problem is because of the ~E10 premium unleaded pump gas we get these days. Years ago gasoline had no ethanol in it.

Ethanol has oxygen molecules in it if that's the right word for it so the higher the percentage of ethanol to gasoline you're burning the richer the AFR mixture has to be because of the oxygen in the ethanol.. for it to run right.
that's how I use to set the mixture on the 77s, just lean of blipping the throttle and surging.
the 930 idle drops down fine, no surging.
this really bugs me why it reads 11 but idles good. I want to know why.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-25-2017, 03:47 AM
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Is your AFR instrument calibrated right?
Regards
Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 07-25-2017, 11:20 AM
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Quote:
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Is your AFR instrument calibrated right?
Regards
Alan
We share the LM, and mine idles around 13, maybe just under.
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Last edited by timc; 07-26-2017 at 07:18 PM..
Old 07-26-2017, 07:14 PM
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Are you using the same type of sensor?
Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 07-26-2017, 08:55 PM
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yea, everything is the same.
his car has the aluminum head, mine has the euro but has been rebuilt, twice.

he has great Afr readings.

if nothing else I want to see the balance between all cylinders.

timc can verify, the car runs and idles great, just bad AFRs. he can also tell ya I get anal about things like this. (where is rawknees for that one).
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 07-27-2017, 04:44 AM
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Do you, or are you able to calibrate the unit when you swap it between cars? I wonder if there is a small discrepancy here. It would make sense. Mine calibrates each time I turn it on, and generally very stable. But every now and then I need to tweek it.
Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 07-27-2017, 11:21 AM
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finally got the colortune.
I have it in #4 right now. not looking forward to taking it out as the copper washer on it is going to fall off.

idle is very rich
I revd it up and the color turned blue like it should.

seems to have a slight miss with it in there.,
at first when I revd it it looked a tad rich but the miss was there. I leaned it out a little and made sure the plug wire was on good. miss was not as bad and flame was blue, idle still rich.

that's all I have done so far.
I want to check all 6 with mixture set like it is.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 09-18-2017, 08:58 AM
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Ok so I check all 6 yesterday.
I abandoned the copper washer on the color tune as I spent half an hour trying to fish it out of #6, the 3rd one I tested.

My original idle afr was around 10.
Mixture in #4 showed rich at idle so I leaned it out.
All 6 showed a nice blue flame at idle and at around 2500.
3 had a little yellow with the blue but not enough to adjust it.
Most cylinders had a miss wilith the color tune in there, some did not.

The car drove fine with the new mixture setting
Idle is now 11.2 BUT cruise at 3k is 15.8 to 16.

Big question is why the color tune showing correct mixture when the LM shows 11.2
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 09-25-2017, 06:14 AM
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