|
|
|
|
|
#1
08-01-2009, 08:59 PM
|
||||
|
||||
|
Retarding Ignition Timing (to improve emissions?)
Reviewing the archives and found this excellent post from ann old thread on retarding timing... to improve emissions.
Quote:
Also, do I need to check the timing BEFORE I retard it? What is the ignition timing spec on these cars? Thanks again.
__________________
Steven 1989 260E (276K miles) 1995 E320 (50K miles) 
|
|
#2
08-01-2009, 11:10 PM
|
|||
|
|||
|
Yes, retarding (like to 2 degrees or hey, even zero while you're at it) makes a huge difference and lowers emissions considerably. But you'll have difficulty driving to the testing center!!!
__________________
08 W251 R350 97 W210 E320 91 W124 300E 86 W126 560SEL 85 W126 380SE Silver 85 W126 380SE Cranberry 79 W123 250 78 W123 280E 75 W114 280
|
|
#3
08-02-2009, 12:36 AM
|
||||
|
||||
Curious if the only thing added to the '90+ cars was JUST the EGR for lower emissions or if the cam and such was changed.
__________________
I'm not a doctor, but I'll have a look.  '85 300SD 245k '87 300SDL 251k '90 300SEL 326k Six others from BMW, GM, and Ford. Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]
|
|
#4
08-02-2009, 07:48 AM
|
||||
|
||||
|
Quote:
__________________
1988 California version 260E (W124) Anthracite Grey/Palomino Owned since new and still going strong and smooth MBCA member Past Mercedes-Benz: 1986 190E Baby Benz 1967 230 Inherited from mom when she downsized 1959 220S Introduced me to the joys of keepin' 'em goin' There are only 10 kinds of people in the world--those who understand binary and those who don't
|
|
#5
08-02-2009, 07:49 AM
|
||||
|
||||
|
Quote:
__________________
1988 California version 260E (W124) Anthracite Grey/Palomino Owned since new and still going strong and smooth MBCA member Past Mercedes-Benz: 1986 190E Baby Benz 1967 230 Inherited from mom when she downsized 1959 220S Introduced me to the joys of keepin' 'em goin' There are only 10 kinds of people in the world--those who understand binary and those who don't
|
|
#6
08-02-2009, 11:09 AM
|
|||
|
|||
|
If this is just to get past the emissions testing, I'd go for it. I wouldn't leave it that way all the time, unless you want poorer fuel economy. I've had to do this for years with my old Jeep to get past the "smog nazis". I retard the timing about 4-6 degrees, lean out the idle mixture (it's carbureted...won't work with F.I. unless you can control idle mixture) and put a BB in the vacuum line going to the vacuum advance on the distributor, and readjust the idle speed. You can also create a temporary small, non visible (to the smog tech.) vacuum leak to further reduce CO and HC emissions. If your state checks for NOX emissions, this won't work very well, as the NOX will increase. Some Benzes don't have vacuum advance (like mine), just vacuum retard. Others have both advance and retard. If yours just has retard, you don't have to plug the line. So far, I haven't had to do anything to my old Benz to pass, knock on wood.
|
|
#7
08-02-2009, 01:56 PM
|
||||
|
||||
|
Quote:
So, this vacuum hose controls ignition timing advance... so blocking it keeps the engine from advancing. And shorting the resistor retards the timing? So, I'm retarding my timing and keeping it from advancing. Is that correct?
__________________
Steven 1989 260E (276K miles) 1995 E320 (50K miles)
|
|
#8
08-03-2009, 08:32 PM
|
||||
|
||||
|
Quote:
Yeah the air pump I know of (mine fell off mysteriously), figured they went to a diff cam profile that doesn't self EGR like the '89 and older did. Now I know. Now I wonder if the '90+ have a hotter cam profile (somewhat) and just used the EGR to drop the NOx lower than the '89 and earlier.
__________________
I'm not a doctor, but I'll have a look. '85 300SD 245k '87 300SDL 251k '90 300SEL 326k Six others from BMW, GM, and Ford. Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]
|
 |
| Bookmarks |
| Thread Tools | |
| Display Modes | |
|
|
Linear Mode
