bronchole
Driveway flexing!
- Joined
- May 13, 2009
- Messages
- 792
- Reaction score
- 50
- City, State
- Los Angeles, CA
- Year, Model & Trim Level
- 1997 Monsterneer
- Callsign
- KI6MCO
The car:
2005 2WD 4.0 automatic with about 110K miles on it.
The symptoms:
Check Engine light comes back on within 20-40 miles of being reset
P0193 code (fuel pressure sensor high)
Poor gas millage, around 12 MPG (was about 18 MPG a year ago)
Occasionally runs slightly rough, mainly at idle
We ran the Mountaineer for a few months with the CEL on but I have to get a smog inspection in order to renew the registration so it became time to fix it. I replaced the fuel pressure sensor with no change to its behavior . It still throws the code within a few 10's of miles.
I did some data logging with my OBD scanner monitoring the fuel pressure relative to manifold pressure. It shows that the fuel pressure is normally about 40PSI, dithering a couple PSI (about +/- 2 PSI). I could see the changes in PSI when I accelerated and decelerated and I could see the computer respond to the change and drive the PSI back to the desired 40 PSI. Pretty cool stuff.
Data Logging as my wife was freeway driving for a few 10's of miles, sure enough, the PSI shot up to a dead solid 60 PSI +/-0 PSI. There was no noticeable impact to the way the motor was running. I suspect that 60 PSI is the max output of the sensor or the ECU input tops out at that level of signal. After a minute or 2 the CEL comes on with P0193 again. I clear it while we are driving down the freeway. By the time I get back to the data logging screen the PSI is back down to 40 PSI. More 10's of miles the problem repeats.
With the engine running and the data logger running (seeing 40 PSI) I went around the engine compartment wiggling all of the harnesses I could reach. No change to PSI, no change to how the engine runs.
Just for general interest I decided to remove the fuel pump relay while the engine is running to see how the PSI would respond. As you would expect the PSI immediately started to drop and after a second or 2 the motor stalls. Pretty predictable.
The next test I would love to do is pull the fuel pump relay when it thinks it sees 60 PSI and see what happens. That would tell me if it was an actual 60 PSI issue or some problem with the sensor, wiring or ECU.
Looking for any other thoughts on this.
thanks,
Dan
2005 2WD 4.0 automatic with about 110K miles on it.
The symptoms:
Check Engine light comes back on within 20-40 miles of being reset
P0193 code (fuel pressure sensor high)
Poor gas millage, around 12 MPG (was about 18 MPG a year ago)
Occasionally runs slightly rough, mainly at idle
We ran the Mountaineer for a few months with the CEL on but I have to get a smog inspection in order to renew the registration so it became time to fix it. I replaced the fuel pressure sensor with no change to its behavior . It still throws the code within a few 10's of miles.
I did some data logging with my OBD scanner monitoring the fuel pressure relative to manifold pressure. It shows that the fuel pressure is normally about 40PSI, dithering a couple PSI (about +/- 2 PSI). I could see the changes in PSI when I accelerated and decelerated and I could see the computer respond to the change and drive the PSI back to the desired 40 PSI. Pretty cool stuff.
Data Logging as my wife was freeway driving for a few 10's of miles, sure enough, the PSI shot up to a dead solid 60 PSI +/-0 PSI. There was no noticeable impact to the way the motor was running. I suspect that 60 PSI is the max output of the sensor or the ECU input tops out at that level of signal. After a minute or 2 the CEL comes on with P0193 again. I clear it while we are driving down the freeway. By the time I get back to the data logging screen the PSI is back down to 40 PSI. More 10's of miles the problem repeats.
With the engine running and the data logger running (seeing 40 PSI) I went around the engine compartment wiggling all of the harnesses I could reach. No change to PSI, no change to how the engine runs.
Just for general interest I decided to remove the fuel pump relay while the engine is running to see how the PSI would respond. As you would expect the PSI immediately started to drop and after a second or 2 the motor stalls. Pretty predictable.
The next test I would love to do is pull the fuel pump relay when it thinks it sees 60 PSI and see what happens. That would tell me if it was an actual 60 PSI issue or some problem with the sensor, wiring or ECU.
Looking for any other thoughts on this.
thanks,
Dan