Setup Injection pump help much appreciated

[450sl]

Hi All,

Just finished my 280-1970 complete engine rebuild , new throttlevalve bushings , new linkages , slightly hotter cam , early exhaust headers , 123 ignition, innovate mtx wideband.

Got the engine running now with decent idling , and now its nearly spring and when winter road-salt is all cleared off , its time for optimising the IP on the road.

Few questions:

#1    Just to make sure :    Are these the settings I should look for ?    (i just translated the BBB numbers into a  Co to AFR chart conversiontable)

                               Idle  750-800   Co 3,5-4,5  =  AFR   12,8   -13,2
                    Lower partial    1500   Co 1,5-3,0 =  AFR   13,4   -13,95
                                          3000+   C0 0,2-1,5 =  AFR  13,95  -14,5
                       Full load      3000+   Co 2,0-4,0 =  AFR  12,85 -13,2

         Or should i just look for a general  on low side of 14,7?


 #2   Is there a particular adjusting-sequence in  main rack ,black and white screws ,barometric-comp.  i should follow ?

Help very much appreciated.

Thanks
Mark

[ja17]

Hello Mark,

Make sure your linkages are correct and the fuel pressure is correct first. Also make sure your distributor if functioning correctly with correct timing. You should have no internal fuel leaks or vacuum leaks. You r injectors should be atomizing the fuel well.  The internal rack adjustment screw or baro shims will change the mixture over all rpms ranges. Use these if you need to make an over-all change. The idle thumb screw and the internal governor screws (black, white) will dial in the particular speed range for you. 

[Tyler S]

Assuming everything else is ideal as Joe suggests, Make sure to get the engine good and hot before any adjustments. The black and white governor screws should be the LAST thing you mess with. Only if you find an air fuel issue at a peticular rpm range. Generally you will have a lean or rich mixture across the board and can compensate with the main rack screw or baro shims. Just make sure the engine is on the rich side of 14.7 under load and doesnt ping. You should be seeing 12-13 under load at 3/4 to full throttle.

[450sl]

Thanks Joe and Tyler, have had some good tips from with Jeff280sl as well .


Yes , i think all settings are good , renewed all linkages and even replaced airvalve bearings so there is no play to be found on the linkage system.

My Ip was recalibrated by a specialist last year before i rebuild my engine completely.

After the first testrun on the road , it runs a bit lean , wonder if this is a result of the better working engine , the earlier type exhaustheaders , or both.

Mark