abronson47 Posted September 5, 2022 Share Posted September 5, 2022 I’ve had my truck since June, and I can’t get it registered because it won’t pass emissions currently. I live in Salt Lake City, Utah. The threshold here for gas leaving the exhaust at idle is 800 PPM. Mine is currently throwing 1,830 PPM. I checked the timing on the truck and it was somewhere around 30° advanced. We set it back to TDC, advanced it to 6° because our elevation here is 6100 ft, and readjusted the throttle screw on the carb. It idles good, but it diesels when I shut it off. It has no power when you step on it, and the truck tries to die on me coming into second gear. It’s a 1985 Ford F-250 4x4 with the 460 motor. I can’t find any diagrams on the carb that’s on it, it’s a Holley manufactured for Motorcraft carb. Can’t find the air mixture screws or where to even set it from here. Any help would be INCREDIBLE. The numbers on the carb are 50004-1 E3TE-5910-PO. Link to comment Share on other sites More sharing options...
85lebaront2 Posted September 6, 2022 Share Posted September 6, 2022 Your idle mixture screws are in the throttle body on the front under the float bowl. I have a copy of the service manual for these, they were used from 1979-1987. If your idle is extremely rich, the power valve may be bad, and I have seen the secondary metering body warp on these and make them overly rich. Timing should probably be around 10° BTDC with no vacuum connected, reconnecting it should probably put it near 30° BTDC if it is full vacuum like the later ones. 1983 was the first year back for the 460 and most of the specs were holdovers from 1979. I show 2 different emission vacuum diagrams for a 1983. one is pretty straight forward, the other looks more like the later models. Link to comment Share on other sites More sharing options...
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