fyrfytr33
Member
- Joined
- October 13, 2010
- Messages
- 18
- Reaction score
- 0
- City, State
- Mount Vernon, WA
- Year, Model & Trim Level
- '98 Explorer, 4.0L OHV
So I have a 1998 Ford Explorer, 4.0L OHV (VIN X) with 129,000 miles. CEL came on and the idle got rough. Had the codes checked and came up with P0171 and P0174, lean bank 1&2. I replaced the upper and lower intake gaskets as well as the EGR o-ring. While I was in there I cleaned the intake plenum, replaced spark plugs, rebuilt the fuel injectors and replaced the o-rings.
When started I found it had a bad miss (fixed by hooking the spark plug wires up correctly) and the lean codes returned. I found the DPFE was melted and replaced it and the hoses to the manifold. Reset the codes and started, the miss was gone but the idle remained rough and the CEL came back with the same codes. Ran a data capture and noticed I get 0.0vdc from all three o2 sensors and -100% fuel trim on both banks and both long and short term trim levels. Checked resistance of the o2 sensors and continuity from the PCM plug to the sensors, all seemed in order.
Any ideas where to look?
Started checking other components;
PCV Tests good
O2 sensors B1/S1 4.6ohms @60* F
B2/S1 4.2ohms @60* F
Post Cat Sen 4.2ohms @ 60* F
MAF Term A to grd 12vdc
Term B to pos 12vdc
Term C to pos 12vdc
Term D to grd Fluctuates w/RPM 700-4000rpm .80-2.50vdc
TP sensor .94vdc @ idle 4.73vdc @ WOT
IAC valve Tests good
IAT sensor Tests good
ECT sensor Tests good
Fuel pressure KOEO 36psi
KOER 30psi
KOER press reg vac removed 38psi
KOEO 30 min leak down 38psi
Intake vacuum
EVR solenoid Possibly not working No vacuum pump
EGR valve Possibly not working No vacuum pump
So I replaced the plug wires, put the original injectors back in, double checked all connections, put clamps on some vacuum lines, double checked intake stud torque. Warmed up the engine and hooked up the computer and reset the DTC. Seems to be idling better but not perfect. No new codes as of yet.
But I’m perplexed by the fact I still get 0.0vdc from all three o2 sensors and -100% fuel trim on both banks and both long and short term trim levels. It remains in closed loop which I believe is what it should do when warm.
Things still to check;
Fuel cap
EGR valve
EVR solenoid
CANP solenoid
CMP sensor
CKP sensor
VS sensor
Now where do I go?
When started I found it had a bad miss (fixed by hooking the spark plug wires up correctly) and the lean codes returned. I found the DPFE was melted and replaced it and the hoses to the manifold. Reset the codes and started, the miss was gone but the idle remained rough and the CEL came back with the same codes. Ran a data capture and noticed I get 0.0vdc from all three o2 sensors and -100% fuel trim on both banks and both long and short term trim levels. Checked resistance of the o2 sensors and continuity from the PCM plug to the sensors, all seemed in order.
Any ideas where to look?
Started checking other components;
PCV Tests good
O2 sensors B1/S1 4.6ohms @60* F
B2/S1 4.2ohms @60* F
Post Cat Sen 4.2ohms @ 60* F
MAF Term A to grd 12vdc
Term B to pos 12vdc
Term C to pos 12vdc
Term D to grd Fluctuates w/RPM 700-4000rpm .80-2.50vdc
TP sensor .94vdc @ idle 4.73vdc @ WOT
IAC valve Tests good
IAT sensor Tests good
ECT sensor Tests good
Fuel pressure KOEO 36psi
KOER 30psi
KOER press reg vac removed 38psi
KOEO 30 min leak down 38psi
Intake vacuum
EVR solenoid Possibly not working No vacuum pump
EGR valve Possibly not working No vacuum pump
So I replaced the plug wires, put the original injectors back in, double checked all connections, put clamps on some vacuum lines, double checked intake stud torque. Warmed up the engine and hooked up the computer and reset the DTC. Seems to be idling better but not perfect. No new codes as of yet.
But I’m perplexed by the fact I still get 0.0vdc from all three o2 sensors and -100% fuel trim on both banks and both long and short term trim levels. It remains in closed loop which I believe is what it should do when warm.
Things still to check;
Fuel cap
EGR valve
EVR solenoid
CANP solenoid
CMP sensor
CKP sensor
VS sensor
Now where do I go?