Join Date: Jan 2003
Location: Gainesville, FL, USA
Feedback Score: 0 reviews
Re: Symptoms of bad injectors
I understand that if the timing is more retarded than 6.5* BTDC then there will be a miss at idle. John's suggestion about checking injs, by loosening them is correct, if you have a real bad one there will be no change in that cylinder when you loosen it. However the fact that there is change doesn't mean that inj. is good. Just that it's firing. There is a specification for pop off pressure and spray pattern, if these are off enough, it can cause problems. Black smoke usually means too much fuel or not enough air so unburned fuel. Possible causes, bad injectors, advanced timing, plugged fuel return lines, plugged fuel or air filter. I know I said retarded timing but it could also be too far advanced. You should probably play with the timing some and see if that makes a difference. Here's the easy way, start it if you can get it running, remove the smaller connector behind the FSS, this is the cold timing advance, it advances the timing 2-3 degrees, so unplugging it(assuming it is connected and operational) will have the same effect as retarding the timing 2-3 degrees. If it gets worse or won't satrt, assume you are too retarded , if it helps, assume that the timing is too far advanced. Conversely if you want to adbvance the timing without moving the pump put 12V directly to the CTA terminal and that should give you 2-3* of advance...
J.D.'s Fords: 1986 F-250 6.9 diesel Solid State Glow Plug System 3.55 gears C-6 2WD 178,960 miles.... it still runs pretty good!
Wishlist H-max turbo, T19 tranny,
1989 Ford Ranger ga$$er, non runner, soon to be donated or scrapped!