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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Greets.
Well, I'm finishing off my engine tune-up on the 280GE (M110 engine), and am at the CO testing.
Wouldn't you know it-- My Gunson GasTester (which I have used ONCE!!!! in the past) is broken!! I've tried for over a month now to deal with Gunson U.K., and they are completely WORTHLESS. They act like they have never had one fail, and that they have never sold one outside of the UK. No USA contacts or repair facilities.
To make matters worse, there is NO ONE in my city of 400,000 who has a shop with a CO tester, and there are no Dept of Vehicles testing stations within 300 miles of me.
My question: Are there any "ol' timer" methods to arrive at a "safe" fuel mixture. I'm not interested in milking every drop of fuel economy... I'm more interested in arriving at a mixture where I don't HARM my engine.
Any input would be appreciated.
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9965
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
G-AMG - 11/25/2008 1:01 PM
Greets.
Well, I'm finishing off my engine tune-up on the 280GE (M110 engine), and am at the CO testing.
Wouldn't you know it-- My Gunson GasTester (which I have used ONCE!!!! in the past) is broken!! I've tried for over a month now to deal with Gunson U.K., and they are completely WORTHLESS. They act like they have never had one fail, and that they have never sold one outside of the UK. No USA contacts or repair facilities.
To make matters worse, there is NO ONE in my city of 400,000 who has a shop with a CO tester, and there are no Dept of Vehicles testing stations within 300 miles of me.
My question: Are there any "ol' timer" methods to arrive at a "safe" fuel mixture. I'm not interested in milking every drop of fuel economy... I'm more interested in arriving at a mixture where I don't HARM my engine.
Any input would be appreciated.
This should rough it:
1.) Warm up your engine to normal operating temperature; and set your idle with the large white screw using a large flat head screwdriver to about 800 RPM.
2.) Turn the mixture adjustment clockwise with a 3 (?) or 3.5 (?) mm Allen head until the engine idle drops.
3a.) Turn the mixture adjustment counterclockwise about 1/2 turn and readjust the large idle screrw to 800 RPM. You should be pretty close.
or
3b.) If that 1/2 turn in #3 passes a good idle and starts to drop the idle again, set the mixture screw 1/2 way between the two points (too rich & too lean) where the idle speeds drop; and set the idle at 800 RPM with the big white idle adjustment screw.
As said, that should rough it fairly well. I'm working with a very leaky memory on this; so anyone with a better idea, please feel free to over rule me. |
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roughneck
Expert
Date registered: Apr 2006
Location: UK, Germany & USA
Vehicle(s): 270 cdi.300 GD 300 GE.lwb 300 GE.swb. Disco 2
Posts: 4398
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
In the old days I would run the engine up to temp and then turn the co adjuster untill it ran fast then back untill it started hunting and then gentley back untill it started running even, that allways seemed about right. |
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Roly
Elite Veteran
Date registered: Apr 2006
Location: Australia
Vehicle(s): 1999 G500
Posts: 661
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Connect a vacuum gauge to the inlet manifold and adjust the mixture to obtain the highest steady reading. This should correspond to the steadyest hopefully. Engine at normal operating temp. |
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| Re: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Oh PERFECT!!
Thanks all, this was exactly the kind of stuff I was looking for!! |
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512bbi
Expert
Date registered: Jan 2007
Location: North western US and Europe
Vehicle(s): 05G55kge,Range rover classic,clk55amg,ML 430
Posts: 1313
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Temperature of your exhaust is another way ,if you are running cool and you do not smell hydrocarbons......
If there is an air By pass for adjusting idle rpm is best to set the co just right with your air by pass closed all the way and adjust idle rpm with your throttle screw and only use your air by pass only if you can not set it right by the throttle screw only. |
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bram_r
Expert
Date registered: Apr 2007
Location: the Netherlands
Vehicle(s): 1984 MB 280GE, 1982 MB 300GD, 1986 Subaru XT 4WD
Posts: 1659
| Re: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
If you don't know the history of the car, I'd first adjust the throttle plate adjuster bolt (stopper).
With idle air screw (big white screw) fully in, the throttle plate adjuster bolt should be holding the throttle plate far enough open so that the engine barely idles (+/- 600 rpm or so).
After that work on your idle adjuster screw and CO screw for right idle speed and mixture.
...and buy a SUN CO meter...
Bram |
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roughneck
Expert
Date registered: Apr 2006
Location: UK, Germany & USA
Vehicle(s): 270 cdi.300 GD 300 GE.lwb 300 GE.swb. Disco 2
Posts: 4398
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
http://www.frost.co.uk/result_search.asp?keyword=gunson&gclid=CKXTr... |
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Gunson, ehhhh?????
Hmmm, that is the "wonderful" piece of equipment I already own! Mind you, lasted me a whopping ONE USE BEFORE FAILING!!
I first bought/used it around 1 1/2 years ago, and neatly stored it in it's box. (You've seen how anal compulsive I am about my workspace.)
I pull it out last month...... It reads " -16.6 " even after numerous attempts. Then the adjusting knob FALLS OFF into the unit!!
For the last MONTH I have attempted contact with ToolConnection (Gunson's parent company) with no significant help. They have no idea of how to deal with one of their overseas customers.
If you know something (or SOMEONE) regarding Gunson, I would be truly grateful! |
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elevatorbernie
Expert
Date registered: Aug 2006
Location: Vancouver B.C. Canada
Vehicle(s): 1989 280GE
Posts: 1347
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
I just bought a used gunson on ebay cheap...I haven't got it yet...I hope it works. They're not alot of money new. I didn't buy mine from this place but they have alot of info and links about the gunson and a good price too http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ssPageName...
Edited by elevatorbernie 11/25/2008 11:22 PM
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
I think I got the one I have used from Dutch maybe....Been so long I can't remember. Worked fine every year I pulled it out to check CO until I changed to diesel. But maybe their build quality was better on the older ones, or maybe those were simpler or something. The model I have isn't in their current catalog. It's the one pictured in the CGW article.
I don't have the box. The Gunson is propped up on a shelf between an old Heathkit 'scope, a pile of Jaguar water pump castings, and half a Lucas generator. My workspace is closer to a pile of something that is ejected anally than it is to anything anal retentive or compulsive. The Gunson seems to keep on ticking though. Maybe it enjoys the company of the Lucas genny. Yours might just be grumpy at hanging around with all those German tools. Let me know if you want me to send you a rusty Dunlop brake cylinder or a leaky Lucas ignitoin coil to cheer it up. 
-Dave G. |
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Yes, Dave, it probably IS my fault for not smearing it with British Brake Fluid, and Ignition coil Oil. Ha Ha
This is how it looks, and this is the reading I get at warm-up. The other 6 times it read -16.6, but now this is the reading.
Forutnately, I tracked down the individual who "distributes" them in the USA (sounds like he works out of his house), and he will try to "Go to bat" for me.
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
G-AMG - 11/26/2008 9:45 AM
... I tracked down the individual who "distributes" them in the USA (sounds like he works out of his house), and he will try to "Go to bat" for me.
Is this the same guy as the ad on CGW?
http://www.clubgwagen.com/specials.php?pageTitle=Auto%20Expert%20Pr...
I'd expect that page is way out of date, but you never know. I think I talked to him once. Out of FL or GA or something? Foggy memory. Hope it works out, it's been a handy tool for me. But the methods mentioned above work okay too. The M110 doesn't seem to be too fussy in that regard.
Good luck!
-Dave G.
PS - looks like the gastester.com link has moved on to bigger and better things, but http://www.autoexpertproducts.com/index.htm is still out there and appears to still be doing Gunson stuff.
Edited by hipine 11/26/2008 12:28 PM
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Hipine,
Yes, I purchased the unit from the that same expertproducts.com guy, but his wife told me "tough luck".
The other guy I found is the main "importer" for the USA. But, like he says, you "can't repair" them. |
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mgrays
Regular
Date registered: Oct 2007
Location: UK, Scot, Aberdeen
Vehicle(s): 300GDSt 1988
Posts: 84
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Use a Lambda sensor with output tuned to 0.8 Volts being 14:1 (ie lambda) .. or maybe 0.76 Volt if you want a little lean.
Plenty of wideband lambda tuning boxes now you can get.. but a basic scrapper narrow/standard lambda with the right power supply would do the business.. Half think it is 5V which you could do from a resistance bridge across your battery (or some mobile phone chargers). It is better if you have a lambda sensor right up and hot at the manifold but they still work a bit if jammed in the tail pipe.. The thread is a coarse spark plug but you can buy weld on bungs if you want to do it right. This is basically all your broken bit of kit is anyway... I am guessing. A lash together from a breaker and bits should be under $50.
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
Great point! Help your G and have fun with a little project along the way. Here's one good article:
http://autospeed.com/cms/A_2191/article.html
But a quick google for "mixture meter" will get a whole spectrum from plug and play to junk yard specials.
-Dave G. |
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: Any "Old Sage" Advice on how to do Mixture Adjustment W/O CO Tester??
mgrays,
You state it should "work a bit" if shoved up the tail pipe? Do you think there is a "reliable" accuracy?
Since I have no Lambda sensor, I would assume this would require drilling a hold in the exhaust system?
Thanks for the input! |
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