Full range injection pump adjustment

[alan]

Does this adjuster located at the rear of the pump, under the M6 bolt, have detents?
I am trying to adjust for more fuel, but am having trouble telling if I am actually making an adjustment or not.
When inserting a screwdriver, I can feel something moving under slight spring pressure, then when that runs out of travel, something else moves with more spring pressure (The rack I'm guessing)
When turning the screwdriver, it is hard to tell if anything is actually turning.

Should I feel detents or not?

Thanks.

[alan]

Ok, after removing the solenoid I can see there is a lever in the way of the adjusting screw.
Now to figure out what this lever is, and why I've missed it in the manuals and webpages.

[alan]

After removing the lower plate under the solenoid, I was able to adjust the screw. Yes it does have detents.
It was a pain to reach, I had to go from the underside to see what I was doing, and was not able to go straight on the screw, had to adjust from an angle.

I will probably be taking this plate off many times in the future.
Apparently this car had an injection pump from a 250. The replacement pump from the rebuilder was different, so not sure if it is for this engine or not
This is on a 69 280SL.

Fuel mixture was rich at idle, lean while cruising, and dangerously lean under load.

Right now I am 6 clicks lean on the idle adjustment, and 3 clicks rich on the full range adjustment.
It seems like this engine likes to idle rich, around 12.5 : 1 A/F ratio.
Currently cruising around 13:1, but accelerating under load mixture is lean, around 18:1 at full throttle. (better after the 3 clicks adjustment, was maxing the gauge out at 22:1 A/F ratio)
I'm not sure if I need to go after the lower partial load range adjustment or not.

I am also having a problem of good mixture at idle in park, but now it is lean idling in reverse or drive. I was not having this problem before the full load adjustment, was also at 3 clicks lean on the idle adj. before.

[Rodolfo]

Linkage tour .
You should start with the 233 mm.  And make sure you have a closed air inlet at idle and really use the normal idle channel.

[alan]

Thanks, I have gone through the linkages as described in the manual.
Throttle body has been checked, and rests on the stop when the blade is fully closed, and "grips slightly" as described in the manual
I have the injection pump linkage at 225mm. It was set at 210mm before.
I can not make it any longer, or the linkage rests on the constant speed lifting solenoid "idle up solenoid". I have moved the adjusting disc all the way in, to prevent the throttle and injection pump from being held open.
However if I lengthen the injection pump linkage any more, they will be held open.
I don't believe this to be an issue, as the throttle body, and injection pump lever, rest on the idle stops, and the full throttle stops in sync with each other.

The engine has been rebuilt, injection pump was rebuilt, and I personally set the camshaft timing, injection pump timing, and ignition timing to specs.

I am getting close with the fuel mixture. Right now I am 3 clicks rich on the full load adjustment, and 3 clicks lean on the idle.
I plan on going 2 clicks richer on full load. Accelerating at full throttle gives a steady 15:1 A/F ratio. Hopefully 2 clicks will get me around 13:1
Anything less than full throttle though, and I get around 18:1 A/F ratio.
This leads me to believe I need to adjust the upper partial load range screws. The manual warns never to adjust these, otherwise the full load range, and entire engine range will no longer have control.
Maybe instead of full load adjustment, I need upper partial load adjustment?

Lower loads are not too bad, and I think I can get the idle mixture where it needs to be after the other adjustments are done.

Thanks for any help.

[Garry]

Alan,

You will be unable to do the critical Linkage Tour as described in our Technical Manual without being a Full Member and having access to that area of the Manual.  its well worth the $30 membership cost and will pay for its self in that one bit of access and ability to correctly set up your car.

Garry
Membership Administrator

[twistedtree]

You might still have a meaningful linkage issue.  Making sure the FIP and throttle flap come off the stops at the same time is important, and you have that one covered.  But the start and stop positions of the cross arm matters too.  Each lever arm in the system moves through a certain arc, and that translates into movements of the links.  Depending on where you are in the arc, you will get different amounts of movement out of the connected rods.  The alignment hole in the bracket at the manifold end of the cross rod is used to ensure the rod's lever arms are in the right part of their arc when the FIP and throttle are on their stops.  If that's off then movement of the FIP will not translate into the correct corresponding throttle flap movement.  The fact that your constant running solenoid is not aligning correctly suggests that the cross rod is not rotated correctly.  It might be worth a closer look.  Garry is correct that the Linkage Tour is worth every cent of the membership cost.  Hopefully my description here helps, but it's hard to describe.