Discussion
Dunno, but a quick 'google' turned up some interesting sources. Seems like you can do a fair bit of diagnosis just using an analogue multimeter:
www.therangerstation.com/tech_library/OBD_I.html
www.fordf150.net/howto/eecivcodes.php
www.corral.net/tech/maintenance/eecivtest.html
www.easttraining.com/courses/ford_ecd.htm
www.fordscorpio.co.uk/star.htm
www.therangerstation.com/tech_library/OBD_I.html
www.fordf150.net/howto/eecivcodes.php
www.corral.net/tech/maintenance/eecivtest.html
www.easttraining.com/courses/ford_ecd.htm
www.fordscorpio.co.uk/star.htm
In answer to original question, yes it does - it has various "limp home" modes for most of the sensors, but not all.
Very interesting links Peter, although most of them refer to the later OBD2 system, whereas the 2.9 S Series used the earlier OBD1 (as far as I have seen) which is a 3-pin diagnostic plug.
Don't know about using a voltmeter, but I did manage to make a code reader for a (very) few pounds following basically the same principles as are shown in some of those diagrams. Unfortunately I then found it doesn't work on my car - it did work on a Granada I tried it on though. I connected up a proprietary code reader and that didn't work properly either - I suspect it's the ECU earth, which is good enough for normal operation but not giving a diagnostic signal earth.
Very interesting links Peter, although most of them refer to the later OBD2 system, whereas the 2.9 S Series used the earlier OBD1 (as far as I have seen) which is a 3-pin diagnostic plug.
Don't know about using a voltmeter, but I did manage to make a code reader for a (very) few pounds following basically the same principles as are shown in some of those diagrams. Unfortunately I then found it doesn't work on my car - it did work on a Granada I tried it on though. I connected up a proprietary code reader and that didn't work properly either - I suspect it's the ECU earth, which is good enough for normal operation but not giving a diagnostic signal earth.
tvrgit said:
In answer to original question, yes it does - it has various "limp home" modes for most of the sensors, but not all.
thanks.... hopefully new lambda sensors may make a big difference then....
drove the car today with the lambdas disconnected so in theory it was running a default fuel mix as it would have no way of knowing the real mix. Car ran the same as before at idle and through the mid ranges.. so it is possibly a safe mode the ECU has dropped into... will report back more when the new ones arrive....
AFAIU, the ECU will switch into LOS mode when one of its key sensors (TP, Engine Coolant Sensor, AFM etc) starts giving out unexpected or 'spurious' signals. Not being familiar with the Cat models, I'm not sure if a defective Lambda sensor would trip the ECU into LOS or not.
Regardless, if with new Lambdas fitted the car runs the same then it may be worth taking a look at the other critical sensors. I spent ages trying to find a similar fault with mine and it turned out to be a completely gunked up AFM heated wire.
Regardless, if with new Lambdas fitted the car runs the same then it may be worth taking a look at the other critical sensors. I spent ages trying to find a similar fault with mine and it turned out to be a completely gunked up AFM heated wire.
sotonS2 said:
AFAIU, the ECU will switch into LOS mode when one of its key sensors (TP, Engine Coolant Sensor, AFM etc) starts giving out unexpected or 'spurious' signals. Not being familiar with the Cat models, I'm not sure if a defective Lambda sensor would trip the ECU into LOS or not.
Regardless, if with new Lambdas fitted the car runs the same then it may be worth taking a look at the other critical sensors. I spent ages trying to find a similar fault with mine and it turned out to be a completely gunked up AFM heated wire.
yep.... replaced the MAP sensor and now the Lambdas... then will see how it goes from there... sensors coming in from Germany and will be here friday.
Gassing Station | S Series | Top of Page | What's New | My Stuff