Ford Fiesta EECV 1.25 Zetec DH - Drivability problems, heitation under load, holding backArchived Message
Posted by John Batten on January 13, 2004, 10:28 am
HI All,
I have this Fiesta with a driveability problem. Vehicle has hesitation under light load, nothing major but if your being fussy it can be noticed, the real fault comes in when in 4th & 5th gears and you reach 4500 rpm in 4th or 4000rpm in 5th. At this point the car will hold back (feels like fuel starvation), if you ease back on the throttle in can be driven through but only to happen again a few hundred rpm up the rev range. At times in 5th the vehicle has at 4000rpm held back and when throttle is released and put back on no difference and it will stay like this for 10 seconds.
Looking at live data on Auto diagnos when the fault happens the vehicle drops out of closed loop, AFR goes fro 11.01:1 to 14.51:1, evap duty 100% to 0%, can purge on to off, injector pulse width 10.43ms to 7.94ms, stft 33.4% to 1%. The control unit appears to be doing whatever it can to reduce fuel input. It stays like this for a few seconds and as soon as afr drops below 14.51 the vehicle will pick up and drive again.
I have inspected all waveforms from every sensor and actuator (in the workshop)and nothing appears to be out of the ordinary. Fuel pressure is to spec both in workshop and whilst on road test, flow at idle is 200ml in 30 secs ( i dont have a spec for this).
All Kam have been cleared and re learnt. Ratch is at .8v.
Any ideas on this one would be great, as my next step is to remove control unit and check waveforms whilst on road test (control unit not a lot og fun to remove).