Postby Hook » December 19th, 2014, 2:57 pm
I'm not surprised that nobody started by asking if you checked for error codes.
Driveablility issues could well be related to improper air/fuel mixture, which is governed by several things:
MAF (your factory vane type has a built in intake air temperature sensor)
Oxygen sensor
Throttle position sensor
Coolant temperature sensor
Faulty injectors
Faulty ECU
Then there are other issues that can cause this-
Faulty ignition system (bad coil, broken wires etc.)
Vacuum leak or improperly connected vacuum lines
Wrong timing (ignition timing and/or cam timing)
Clogged or leaky injectors
Bad fuel pressure regulator
Broken harness
Not all of these will throw error codes, and some will only throw a code when the component has failed completely. But start with a diagnostic scan that can give you throttle angle, ignition timing, air temp etc.
Also, a plus is that it idles. Use that to your advantage. Spray carb cleaner on your vacuum lines one by one and look out for any stutter in the engine hum. This will indicate that you've found a leaky line.
Look online for the vacuum diagrams and repair manuals and ensure that everything is connected correctly and properly adjusted.
I wouldn't advocate just swapping ECUs as there are two different types for the silvertop (pre and post June 1995 IIIRC), which have different pinouts and need to be paired with the correct harness to work properly.
Before you get super technical about it, just make sure everything is set the way it should be.
