Author Topic: Injection Pump Rack  (Read 2204 times)


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Injection Pump Rack
« on: April 23, 2014, 01:38:57 »
Greetings to all
I have been working on restoring my car since 1993 or so.  I started out by having the engine overhauled which included sending my injection pump to Fairchild Industries for overhaul.  I have been driving the car since the mid 90's and working on the body and interior.

Now that it is getting near completed, I have started the fine tuning.  I have been getting about 14 Mpg which I knew was not right.  So I have checked the CSV with everything checking out OK.  Next I went to the WRD and noted that there was a lot of sucking air at the pump's air intake filter.  So after playing around, I removed the upper shims from the WRD, which reduced the air flow substantially, but it still suck a little.

After checking the idle mix with the disengaged linkage, I noted that it was running really rich and idled at notably high Rpm when I adjusted the air screw.  So I took out the only lower shim that I found below the WRD.  The motor started with difficulty and soon the RPM was way up again.  

Checking with the linkage, I found it to be running rich, still.  I then went on to adjust the idle mixture knob and noticed that the wire to the CSS was disconnected.  Although I knew that I wanted to lean the mix, I noted that it would not turn clockwise, so I turned it counter clockwise and after 8 clicks it would not turn anymore.  I did connect the CSS and the car would not start.  I'm stuck...  can anyone give this poor back-yard mechanic a little advice?
« Last Edit: April 25, 2014, 07:04:57 by 280SL71 »

Cees Klumper

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Re: Injection Pump Rack
« Reply #1 on: April 23, 2014, 10:49:45 »
First off welcome here. Have you gone through the fuel linkage tour and FI related info in the technical manual?

To lean out the mixture across the range, you want to remove shims from below the barometric pressure compensator, not the WRD.  There's also adjustment screws in the pump, but best check out everything else first. Good luck and let us know how you get on.
Cees Klumper
1969 Mercedes 280 SL automatic white
1986 Nissan 300 ZX 5-speed brown metallic
1990 Ford Bronco II 2WD colonial white


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Re: Injection Pump Rack
« Reply #2 on: May 20, 2014, 02:44:15 »
Welcome to the WRD- Willnot Run Device.   In theory, ???, as the water coolant heats up, the thermostat expands 1, to move the lever in the IP to reduce the fuel flow and 2, close the air valve.  The problem seems to be that the WRD's fuel/air ratio  and volume of both overtake the  fuel/air ratio at idle(idle air screw and IP knob).   Lurtch had a solution - remove the WRD and install a manual screw/bolt to move the lever in the IP to neutral.  This meant a U tube in the coolant line.   Dublin, CA have wide temp swings?