i put my 89 W-150 on the scanner saturday and every thing seemed to look fine. there was only one thing that caught my attention and i have no idea what it is. when scrolling through all the sensors and everything else i noticed one thing that said ADDED FUEL and the number next to it was -272 what is added fuel? and what does it do? any help would be greatly appreciated.
threetwos
03-04-2009, 09:31 AM
Added fuel is the PCM way of adaptive fuel trim either short term or long term. If there is a lean condition it will add, if rich it will pull back some fuel. According to the number, it has been running rich and the PCM has slowly pulled fuel back. Do you have a graphing feature on your scan tool? If so check the Oxygen sensor cross counts, is it switching from rich to lean quickly, and in a consistent manner? Also check the EVAP,, it may be full of fuel,(the charcoal canister next to the drivers side headlight bucket, if it's heavy it's probably full of fuel, dump it and check the hosses and purge solenoid circuit. Also I would display the injectors Pulse width and compare it to the other injector, if one is plugged or dripping during operation it will affect the engine same as a leaky carburetor, if erratic it may just need to be cleaned,(professionally with an injector cleaning system that isolates the fuel system).
DODGEBOY89
03-04-2009, 08:07 PM
thanks. i checked the charcoal can today and it was light and nothing came out. can you dissassemble the charcoal can? i didnt get a chance to look at all the vaccuum lines because it started raining and i got soaking wet. i will let you guys know what i find out. thanks again
threetwos
03-05-2009, 05:40 AM
No, if the charcoal canister is 'light' leave it alone and start checking the basics, vacum gauge hooked up at idle, spark plug wires, plugs, vacum lines, ectt BTW, do you have access to a DMM or scan tool with scope?
