Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Joe on November 11, 2003, 10:21:44
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I was having a dickens of a time getting my car to idle well. Finally, I bought an inexpensive exhaust gas analyzer (EGA), which measures only carbon monoxide (CO) at the exhaust pipe. It cost me $140 plus 10 for shipping, but I justified the purchase of something to be used only rarely because it made sense as an alternative to giving a MB shop $150 to do something I could do.
There are a number of devices available that measure CO2, and other gases, as well as CO, but they cost over $3000.
The device worked well, I think, and now the car idles very well. The CO was around 8% when I started, and is now around 4%. The correct range is 3.5 - 4.5%, so I am in the middle. It probably took an hour and a half to do this the first time, including the 20 minutes or so required to allow the EGA to adjust to ambient conditions.
A brief tutorial on what I learned and did: Ambient air is usually about 2% CO. The EGA connects via long cables to the car's battery for power. It has a hose about a meter long with a metal tube at the end of the hose. This tube fits into the exhaust pipe, and is centered in the pipe by coil springs attached to the pipe at 90-degree angles. Before the car is started, the EGA is connected and allowed to sit for about 20 minutes. It has a digital readout, and once the reading has stabilized, an adjustment is made to the meter so it reads 2.0%.
Before connecting the EGA it is recommended that the car be driven hard for a few minutes to flush out things and reach operating temperature.
During the 20-minute wait for the EGA to stabilize, the engine will cool down a bit, but it will reach temp again during the testing.
The pipe is inserted into the exhaust pipe and the car is started. The reading will fluctuate for a minute or so, and then stabilize. At this point, adjustments to the screw at the rear of the injection pump and the air screw can be commenced. The use of an EGA for these adjustments is given in both the BBB and the Haynes manual.
The car has two exhaust pipes, of course, each servicing three cylinders. I adjusted the idle mixture for one pipe (to 4.0%) and then checked the other pipe. The reading there was 5.2%. This seems like a significant difference to me, and indicates a problem with fuel delivery to one or more of three cylinders.
I plan to drive the car awhile and then recheck and start to trouble shoot this problem. Now it runs very well, and I think my $150 was money well spent.
The EGA was made by Gunson (in England, I think), and I got it from a company in Florida selling them on ebay. Bought Friday night, shipped on Saturday, arrived on Monday.
I plan to use the EGA on multi-cylinder motorcycle tuning. They are apparently very useful for this.
Any comments on the above are welcomed.
Joe
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Joe:
did you read the latest Star magazine. their is an article by Stu Ritter author of the 300E bible the article goes into what you are talking about. The car choosen was a 1970 280SL. very informative article with many pictures of how to set the linkage and fuel injection up so the car runs as Stu liken to say will chirp the tires in first & second gear. The car used was a four speed . Know as I remember Gunson also makes that spark plug richness tool to set carburators if I am correct. It seems if you are happy with their Gas analyzer than that is perhaps another tool worth investing in for owners doing their own fine tuning and weekend work.
Thank you for informing us of this tool.
Bob Geco
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Group:
the tool Joe purchased Gunson Exhaust Gas Analyzer can be purchased NEW with a one year factory warranty from autoexpertproducts in Boca Raton Florida. 1-800-795-6958 John Abbott.$139.95 plus $11.00 shipping with in the United States.
Bob Geco
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Bob Geco wrote:
... did you read the latest Star magazine. their is an article by Stu Ritter author of the 300E bible the article goes into what you are talking about. The car choosen was a 1970 280SL. very informative article with many pictures of how to set the linkage and fuel injection....
No, I've not seen this article but would like to see it. How does one get it?
Thanks,
Joe
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Joe,
The Star is the club magazine of the MBCA (Mercedes Benz Club of America). It is an excellent full featured magazine produced 6 times per year by MBCA for it's members. (www.mbca.org) I don't know if non-members can get it or not. It is a very good article.
About your analyzer - did you ever consider renting one? Or, have you considered renting yours?
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420
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Thanks, Rodd. I called MBCA, which is only a couple of miles from me, and the nice lady who answered the phone said she'd send me a copy of the magazine. Now if I can call them six times a year without anyone figuring this out, I can see all the articles.
I didn't even think about renting an EGA. I certainly would if I thought one would be available. They may be, but I'm not familiar with a type of rental place that would have these. I'd probably loan mine out to anyone local, but mailing it about would be a nuisance. It's not heavy - probably about 3 pounds (1.4 kg) - though.
Joe
The Star is the club magazine of the MBCA (Mercedes Benz Club of America). It is an excellent full featured magazine produced 6 times per year by MBCA for it's members. (www.mbca.org) I don't know if non-members can get it or not. It is a very good article.
About your analyzer - did you ever consider renting one? Or, have you considered renting yours?
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420
[/quote]
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After reading Joe's comments on the Gunson Gas Analyzer and talking to John Abbott also a German Car fan, I purchased one and look forward to using it to measuring the C/O content on my cars. I figure we would have another technical event at my shop some time in the future and we can pull this out and adjust some rich running SLs.
I hope some of our members read the article by Stu Ritter on adjusting the fuel injection on your 280SL. If anyone needs a copy, I will be more than happy to copy it and send it out to them.
Bob Geco
1968 280SL
1992 300-E sport line
1987 Mustang Lx 5.0.
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Purchased a CO analyzer and I can confirm Joe's comments concerning the ease to operate the device. In my case the mixture was too lean. Three clockwise clicks on the fuel injector pump and some minor adjustment of the air screw has the warm idle at 800 RPM and a co reading of 4.1%. The idle is very smooth. All in all I think the analyzer is a good investment. Takes the guess work out of the equation.
Jeff
Jeff Clute
1970 280SL 4-speed
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Has anybody tried setting the F.I.Pump as per Stu Ritters' write-up??
naj
'Kloines Scheisserle'
65 230SL
68 280SL
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anyone want to sell the meter once done ?if so email me
erickmarciano@hotmail.com
1971 280sl
1962 VW
1954 Allstate vespa
1958 gs150 vespa
1962 gs160 vespa
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was reading the instruction for the gunson and we can't use the tool while the car is being driven and past 300rpm so it wount be usefull to set as per Stu Ritters'
we can only set it @ idle . Right?http://http://www.aep.bigstep.com/DIGITAL.PDF
1971 280sl
1962 VW
1954 Allstate vespa
1958 gs150 vespa
1962 gs160 vespa
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I have a Gunson's Colortune (glass spark plug) which in the past I have used succesfully on my Triumph Spitfire and will use again when my engine starts rotating by itself again (after the rebuild). I am also on the lookout for a reasonably priced used Gastester (CO meter). If I get my hands on one I will report the results here.
For folks in the US, this company sells them:
http://www.gastester.com
Cees Klumper in Amsterdam
'69 white 280 SL automatic
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Hi Bob,
Which issue is the article? Can't find it.
Thanks for your help.
Don
quote:
Originally posted by krwaxbz
Joe:
did you read the latest Star magazine. their is an article by Stu Ritter author of the 300E bible the article goes into what you are talking about. The car choosen was a 1970 280SL. very informative article with many pictures of how to set the linkage and fuel injection up so the car runs as Stu liken to say will chirp the tires in first & second gear. The car used was a four speed . Know as I remember Gunson also makes that spark plug richness tool to set carburators if I am correct. It seems if you are happy with their Gas analyzer than that is perhaps another tool worth investing in for owners doing their own fine tuning and weekend work.
Thank you for informing us of this tool.
Bob Geco
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quote:
Which issue is the article? Can't find it.
Check in the last 4 issues or so. It's fairly recent.
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420
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I found a used Gunson's Professional CO meter on Ebay in Germany (Euro 120) and it came in last week. In April I will be able to get back to the car (I'm teaching at university in February and March in my spare time) and try out this new tuning tool.
Cees Klumper in Amsterdam
'69 white 280 SL automatic
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so, this post was a great find. I have a 66 230 sl that has been idle for 18 months. I hope to have it running soon and I was trying to come up with a plan to get it tuned properly.
A little history on the car, the mechanic obvioulsy did not know much about old sls. the cold start valve was capped off and the injenction pump thermostat was frozen. Both have been sent to hans at H&R to be repaired.
that being said the car ran rich for years an I be the fuel mixture will be off.
once I get the parts from hans back on and verify the csv, thermostat and injenction pump working what else should I do.
I will probably order the gunson co2 analyzer and follow the instructions in the manual. check the timing, and dwell, and try the linkage adjustment procedure that is in another post.
Thoughts?
matt
Matt
66 230 sl - "white"
78 300 D - Blue
98 C230
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quote:
Originally posted by merrill
so, this post was a great find. I have a 66 230 sl that has been idle for 18 months. I hope to have it running soon and I was trying to come up with a plan to get it tuned properly.
I believe there's a procedure for bleeding the power steering box. Might be a good idea for your car that's been sitting a long time.
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420
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Rodd,
I have manual steering, so I did pull the plug and checked the hypoid gear oil level.
the front end was jacked up so I was able to turn the steering lock to lock with out friction.
thanks
matt
Matt
66 230 sl - "white"
78 300 D - Blue
98 C230
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Rodd,
I guess I should have meant my focus was on the ignition - cold start funtion. from what I can tell is the mechanic swapped out the injection pump thinking it was bad when I have verified.
cold start valve - disconnected - sent to hans for repair
warm water thermostat on injenction pump bad - sent to hans for repair
thermo time switch bad - need to order one monday
wrong mixture relay installed - 5 prong not 4 need to change
time switch closes at 1/2 second probably need to adjust.
My guess is the mixture will be way off cause the car was running rich. I will get the c02 reader to assist but I need to figure out how to get the co2 in line and the idel speed air screw set correctly.
matt
Matt
66 230 sl - "white"
78 300 D - Blue
98 C230
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A word of caution.
Have the tester checked against a calibrated one if possible. After setting the CO to 4% I went to a car shop and got to compare the readings. They showed 5.6%. So after that I use 2.4% on my Gunsons CO tester – and the engine runs like a dream.
Per G. Birkeland
69 280 sl aut 834
Norway
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Knirk,
did you set the calibration control to show 2% at the start of test before inserting the probe into the exhaust pipe per the instructinos?
Matt
Matt
66 230 sl - "white"
78 300 D - Blue
98 C230
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I am not familiar with a CO meter. I have used various narrow band air/fuel ratio meters that measure O2 and have been looking at purchasing a wide band A/F gauge.
Can anyone describe the differences between these measurements and the advantages of one over the other?
Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor, MGB 5-Speed
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Jim,
this site, http://www.aep.bigstep.com/ seems to have a lot of information
Matt
66 230 sl - "white"
78 300 D - Blue
98 C230
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Matt,
Yes I did.
Per G. Birkeland
69 280 sl aut 834
Norway
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Matt .... The site you recommended had some reasonable information but mostly on tuning and monitoring the A/F ratio verses measuring CO. I installed a digital engine management system in one of my cars and spent a lot of tiem tuning antweeking it with my narrow band lambda gauge and with a wide band gauge at my dyno shop. One of the items that I have learned is that the theoretical is not optimal an that there is a lot of art in performance engines.
Getting back to 113s, do you know the A/F ratio that you were tuning towards or what 2% and 4% CO relates to in other parameters. Have you done measurements under load on a dyno?
Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor, MGB 5-Speed
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Reserecting an old thread if you don't mind...
So an exhaust gas analyzer measures CO at idle. How do you measure CO at speed? Or is it assumed that the correct setting at idle is "close enough" everywhere else?
Like what Jim asked above, I was wondering if a wideband AFR gauge would be beneficial to use. Jim did you ever figure it out? And have you ever dynoed your 230? :D
Checking Ebay, looks like the Gunson tester went from $130 a few yrs ago to around $230 now. Anyone want to rent theirs?
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I have an old renault 11 that I want to tune up. I have a gunson gas analyser. The haynes manual specifies a co2 level of 1.5. I set the machine up in clear air and after the required time I set the machine to 2. The initial readind was over 10 and I managed to tune it down to 1.5. But should I be tuning down to 3.5
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You do realise that this forum is dedicated to a particular model of Mercedes built in the 1960s don't you?
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I dont suggest you tune it down to 3.5, I suggest you sell the car and buy a Pagoda, it will fix the problem completely. :D ;D ;D
Garry
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Selling a Renault 11 won't even generate enough funds to by a set of rear pads for a pagoda!
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For those of you who have a Gunson CO meter, the zero point needs to be set periodically to insure your unit is properly calibrated. I had an issue with mine and the manufacturer sent me the attached sheet and now the meter reads correctly. The sheet does not tell you that you need to gain access behind the display panel by removal of the screw in the bottom of the unit and separating the housing. ONLY ADJUST SCREWS A & B as described. Do not touch C & D or you're SOL.
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Hello Bob,
I'm trying to get my 280SL to the proper 800rpm at idle speed. Do you have a copy of Stu Ritter article on Star regarding this issue. I cannot access the article as I am not a member of MBCA.
Thank you!
Regards,
Gerardo Schlossberg
1970 280SL
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Hello Group,
I thought I had read every post related to fuel system troubles, but I just now found this thread that seems useful. If anyone has a copy of the referenced article by Stu Riter in Star Magazine I would very much appreciate a copy.
My '68 280SL has never run right since I got it 15 years ago and now that I have recently fixed numerous items the PO had seriously screwed up, it is running even worse! It always starts and idles well when cold, but with my "fixes" it now badly stumbles and finally dies as it warms up and fouls the plugs in no time. I'd like to take a look at the Stu Riter article before I finally give up and turn it over to a professional for possible FIP rebuild.
Regards to all,
Enrique Garcia