VW Polo AAU 1992 - Coughs and hiccups when driven #Archived Message
Posted by Shaun Dale on May 16, 2007, 5:34 pm
I've had this one for 3 months and I've got to admit defeat! Symptoms:- Coughs and hiccups when driven, almost ok on light load, nearly undriveable if you try and give it any throttle. When idling it will often be ok for some time, then it suddenly stops injecting for a short time, the idle motor opens up the engine gasps for air and then it picks up again, occasionally it will stall. So far; Another garage replaced distributor cap and leads, fitted a S/H throttle body. I have: Diagnosed system, no faults recorded, unable to get live data but doubt if there is any available I've 'scoped hall signal from distributor,when engine stumbles it just slows up to reflect the drop in engine revs. Coil drive keeps going ok. Changed both relays in the system. Fitted S/H ECU. Checked wiring and connectors etc. Fuel pressure remains steady when engine stumbles. Checked and cleaned throttle pot on body, gives a smooth resistance change. So what silly thing have I not checked / completely missed? I'm thinking along the lines of faulty ignition lead spiking the ECU now, but frankly can't afford to spend much more time on a job that I will never get my money back on,however I hate to let one get away!