Too lean
cscottyr
06-28-2004, 09:05 AM
Help - I have a troubled ford!
About a month ago I purchased a 1999 Ford Ranger 3.0L 4x4 - 85000 miles. Since then I have had many problems - I have had the auto hubs not disengage - I have had the transfer motor fail in 4 low. I fixed both of those problems - then my belt tensioner decided to let fail. It made a curious chirping noise that would wake the dead and was cyclic with engine speed.
- Even though those problems have been troublesome - the one that has given the most grief has been a lean fuel mixture problem. She runs really rough after the battery has been disconected and the PCM is trying to relearn. It takes a long time for this to get better. Eventually it will get better, but not great. It will always through a lean mixture code p0171 and p0174. I also hear a lot of pinging.
- This is what I have tried so far.
- New 02,s - made it a little better but not great.
- New MAF - no difference
- THe IAC looks new and when unplugged drops engine RPM as it should
- Coolant temp sensor -reads 40k with a cool engine and appears to be ok
- PCV seems ok
- EGR when disconnected helps with the ping - but is probably not the problem. I took the valve off and it operates freely. When closed there is a little leak by the seat. The diaphram that operates the valve is OK.
- I was unable to get the screws out of the TPS- but resistance does change linearly with throttle position. ( ON a side note - MY AC is not working either- The clutch wont engage. Could this have any connection with the WOT relay? I switched the wot relay with the fuel pump relay - no difference. The AC fuse is also ok)
- The Ford dealer said my fuel pressure was ok to the rail - though I dont know how long he watched it for.
- I have not checked crankcase or camshaft sensors.
- The Air manifold temp sensor seemed ok - it had the right resistance for the temp at hand.
- I probably will have the fuel injection cleaned next.
Anyone out there have any other ideas????? ANy help would be greatly apreciated.
cscottyr
About a month ago I purchased a 1999 Ford Ranger 3.0L 4x4 - 85000 miles. Since then I have had many problems - I have had the auto hubs not disengage - I have had the transfer motor fail in 4 low. I fixed both of those problems - then my belt tensioner decided to let fail. It made a curious chirping noise that would wake the dead and was cyclic with engine speed.
- Even though those problems have been troublesome - the one that has given the most grief has been a lean fuel mixture problem. She runs really rough after the battery has been disconected and the PCM is trying to relearn. It takes a long time for this to get better. Eventually it will get better, but not great. It will always through a lean mixture code p0171 and p0174. I also hear a lot of pinging.
- This is what I have tried so far.
- New 02,s - made it a little better but not great.
- New MAF - no difference
- THe IAC looks new and when unplugged drops engine RPM as it should
- Coolant temp sensor -reads 40k with a cool engine and appears to be ok
- PCV seems ok
- EGR when disconnected helps with the ping - but is probably not the problem. I took the valve off and it operates freely. When closed there is a little leak by the seat. The diaphram that operates the valve is OK.
- I was unable to get the screws out of the TPS- but resistance does change linearly with throttle position. ( ON a side note - MY AC is not working either- The clutch wont engage. Could this have any connection with the WOT relay? I switched the wot relay with the fuel pump relay - no difference. The AC fuse is also ok)
- The Ford dealer said my fuel pressure was ok to the rail - though I dont know how long he watched it for.
- I have not checked crankcase or camshaft sensors.
- The Air manifold temp sensor seemed ok - it had the right resistance for the temp at hand.
- I probably will have the fuel injection cleaned next.
Anyone out there have any other ideas????? ANy help would be greatly apreciated.
cscottyr
Automotive Network, Inc., Copyright ©2026