I have a 1988 bronco II that is going through a lot of gas (5-7 mpg city) I also lose power intermittently when driving at any speed. I changed the map sensor but I don't see any obd port for a...
1) The crankshaft position sensor picks up crankshaft position and relays it to the ICM.
2) The ICM uses this to determine base timing and sends this information on to the EEC-IV computer.
3) The EEC-IV computer uses this and other engine load parameters to determine timing advance and sends this information back to the ICM
4) The ICM sends spark to the plugs.
As I understand it, this code indicates that the input signal to the EEC-IV computer (steps 1 and 2) was erratic. When this input is missing, then the computer either fires the spark plugs at the wrong time or not at all. This would contribute to poor performance.
If this were me, the first thing I would do is go to the library and get a hold of a good manual and figure out how to diagnose this thing. I expect it would involve inspecting the CKP, the ICM (which you've replaced, but the TFI module is known to have problems, especially when it gets too hot), and all associated wiring.
The CM 96 indicates an intermittent fault in the fuel pump circuit. Note that the EEC-IV computer does not measure the fuel pressure at the rail; it only monitors the fuel pump circuit and can really only determine if the circuit appears intact or not. While measuring the fuel pressure is a good diagnostic step, as you noted, it can be difficult to set something up that allows you to measure the fuel pressure while driving. I would suggest that, rather than measuring the pressure, measure the current flow through the fuel pump circuit. On a normally operating system, pump current is an indicator of pressure. At higher pressures, the fuel pump draws more current to overcome the higher pressure. As the pressure drops off, the pump current goes down because the pump isn't working as hard. If the current drops to 0, that means the pump shut off. Of course, if the fuel pump is cutting out intermittently, that could contribute to a lack of power.
(On The Other 2 Questions (More Info Please)
Aug 23, 2017 |
1988 Ford Bronco II