Contour Enthusiasts Group Archives Forums General Troubleshooting '95 Contour SE CEL and Codes

Have been away from home and the forums for quite a while (out of country in a BAAAAD place )

My wife's '95 Contour SE is throwing a CEL under odd circumstances:

� During around town driving (even during heavy acceleration) I never get a CEL nor does the ECU post any codes.
� At a constant speed highway cruise (55-70 MPH), I get a CEL for 15-30 seconds every 5 to 15 minutes, with a slight "bogging" of speed (1/2 - 1 MPH loss, then back to set cruise).

I pull the following KOEO code: 111 (All's OK)

I get the following Memory codes:

� 172 & 176: Front and Rear O2 sensors not switching, system is or was lean.
� 543: Fuel pump monitor circuit shows no power.
(there is NO 556 code)

If I reset the codes and run the engine at 2000 RPM fast idle for 10 minutes or so, I get no codes set. I'm positive thet the 172 & 176 (lean) codes are the result of the fuel pump shutting down briefly and that they'll go away when the intermittent F/P glitch is solved.

This problem has been bugging me for about 2 years now (there's an old post about it still floating around). This past March, the cracked insulation, wiring harness recall was performed and I was hoping that it would fix the problem, but no luck. I've swapped the horn relay with the fuel pump relay (they're the same) and that hasn't helped either. I've crawled around the fuel pump circuits and can't see anything wrong.

The engine runs fine and has plenty of power (the UIM/LIM clean-up was done about 8K miles ago and the car easily does over 100 MPH with no engine complaints). It's just that d*mn constant cruise F/P glitch that has me going nutz.

I was hoping that someone here has been through this wringer and had some idea of WTH might be going on. Any and all help would be appreciated.

Kurt

Mine did the same thing a few years ago. I replaced the O2 sensors and then all was good. My mpg increased about 10% also.

The fuel pump code seems fairly common and usually stems from corrosion under the aux fuse/relay box behind the battery. The fuel pump is not really stopping, the feedback is just bad.

Slow pulsating power at mid-throttle does indeed sound like slow O2 response.

The 543 means the fuel circuit shut off because the engine stalled. It's a safety circuit in case you get into a wreck the fuel doesn't keep pumping. Seeing the car is a 95 like mine, I would look for vacuum leaks. Hardest one to find was the broken elbow on the PCV inlet. I did the U/L intakes and changed out various parts in the process like grommets on the IMRC, etc.