Fuel Injection Test/Rebuild

[n/a]

I am currently have a valve job done on my 70 280SL but would also like to test/replace the injectors and maybe have the injection pump rebuilt.  I have had the car for ten years and it has run rich since I bought it.  I took it to a shop and they compensated by letting in more idle air.  It idles around 1100 but doesn't run rich.  Does anyone have any suggestions for where to take the injection pump and injectors.  If there is a place in the MD/DC/NOVA area that would be great.  Thanks!

[A Dalton]

I might suggest you do a search on the setting/adjustments of the fuel mixture control on the rear of the  pump.
 If they added air  via bleed screw and the idle speed increased to 1100 , that indicates the pump settings are too rich and could be as simple as a couple of notch/clicks on the fuel knob on the rear of the pump.
 [ CCW direction to lean. CW to enrichen ]
If the fuel from the pump is set right , you should not be able to increase the idle speed that much by adding air at the bleed/air screw.
 That would be a first check before anything drastic..
Also check all links, etc
There is tons of pump setting info here..

[n/a]

The idle bleed air was adjusted as a last resort after the mixture could not be leaned using the adjustment knobs on the pump.  They used an exhaust gas analyzer while making the adjustments.

[A Dalton]

quote:Originally posted by mdorsey

The idle bleed air was adjusted as a last resort after the mixture could not be leaned using the adjustment knobs on the pump.  They used an exhaust gas analyzer while making the adjustments.

 OK..
 I only mentioned it b/c I see so many tune guys that know where the air bleed is, but have no idea of the rear pump control and the correlation of the two.
 The next possible [ and very common rich condition on these style pumps] is when the max adjustments are made and still can not get gas Analyzer to specs,  one can remove shims on WRD and barometric compensator. These spacings change mix across the board.  One knows the proper shims distance is attained and is in the ballpark when the idle fuel knob clicks are in about 8 clicks as a base line and the CO is specs with approx 800-900 rpm at idle.
 But , a rebuilt pump will have those specs already done.

[glennard]

quote:Originally posted by mdorsey

I am currently have a valve job done on my 70 280SL but would also like to test/replace the injectors and maybe have the injection pump rebuilt.  I have had the car for ten years and it has run rich since I bought it.  I took it to a shop and they compensated by letting in more idle air.  It idles around 1100 but doesn't run rich.  Does anyone have any suggestions for where to take the injection pump and injectors.  If there is a place in the MD/DC/NOVA area that would be great.  Thanks!

Got a '64 230SL last year that could not get out of its own way-2nd gear to get up grade.  After valves, linkage, CSV, tuning, etc. it idled at 2000 rpm -with fly weights backed out.  My solution was to adjust stop on injection pump shaft/lever-let the rack return, rotate the helix to let less fuel in, etc.  Back to 800 rpm - with power and engine has that straight six ohc purr. My guess is someone previously adjusted the stop.  Any comments?  Anybody have experience with those stops?

[rwmastel]

Mike,

First, there are LOTS of posts about the fuel injection system on this site.  If you want to eductate yourself more, use the Search tool (link in upper right corner).  Typical suggestions are to set every adjustment rod back to factor spec length, replace worn linkage joints, and some other stuff I can't recall now.

Second, there are LOTS of owners in your area.  If you question your mechanic or shop, let us know who it is and members near you will probably have an opinion (positive or negative).

Third, if it really comes down to an Injection Pump rebuild or a new set of injectors, Hans at H&R will be the closest to you.

H & R Fuel Injection, Ltd
360 Knickerbocker Ave # 12
Bohemia, NY 11716
631-589-1600

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420