Hi ya Andy, had a thought about ptu failures after getting involved with Ken`s probs after the timing belt change.
I have watched with interest the increase number of failures of these units and have a couple of idea`s you may have a view on.
Firstly is seems to be acknowledged that the series 1 units suffer the overheat, solder failure internally that leads to intermittent or complete failure.My thoughts on the reliability of the unit is mixed as some of them are failing after 80k, 90k or 100k+ miles or after 10 or more years service,I do not think this constitutes a failure in design but points to an external cause in use.
The under bonnet heat and location I feel may be a contributor but my electrical background is pulling me away from that. I see evidence of heat related damage in my line of work in many mains powered systems that fry the insulation off cables, distort 1/2" thick busbars and fracture porcelain insulators. The key cause almost all times is poor electrical connections that have led to increased current draw that eventually results in overheating and further failure of the poor conection resulting in a system failure through disconnection of the poor connection or damage to other components.
Having looked only externally at the ptu units not internally like yourself I see many with corroded prongs or loose connectors,my thoughts are as above the possible rise in current caused by the poor connections is the reason for the internal failure due to heat build up. It would from my experience seem likely that a poor connection at the connector would initially cause misfire or non starting that may alert the owner to a problem and a cure (tighten connection or make good)However a slow build up of corrosion could over a period of time cause excess current draw on maybe one or two output`s only, slowly causing the internal soldering to fail? But also I thing there is a more likely chance that a poor connection to more than a couple of the outputs would lead to a rapid internal heat up due to overcurrent and this could happen in a matter of minutes and result in a fried ptu,this would explain how sudden unexpected failure can occur.In Ken`s case after the garage refitting the ptu I believe a poor connection was made as the spring clip was missing! then almost immediatly the damage was done.
When substituting my ptu for his the car started and ran perfectly,after reversing them it would not even start so the whole unit was damaged, again pointing to a single catastrophic failure in one go.
I suppose my point is this, if my theory is correct the corrosion of the terminals and security of the connectors is the main if not all causes of ptu failure with the damaged internal soldering the result not the cause, and checking this must then be added to the service schedule of all our car`s as a damage preventative measure? what do you think?
Hi ya Andy, had a thought about ptu failures after getting involved with Ken`s probs after the timing belt change.
I have watched with interest the increase number of failures of these units and have a couple of idea`s you may have a view on.
Firstly is seems to be acknowledged that the series 1 units suffer the overheat, solder failure internally that leads to intermittent or complete failure.My thoughts on the reliability of the unit is mixed as some of them are failing after 80k, 90k or 100k+ miles or after 10 or more years service,I do not think this constitutes a failure in design but points to an external cause in use.
The under bonnet heat and location I feel may be a contributor but my electrical background is pulling me away from that. I see evidence of heat related damage in my line of work in many mains powered systems that fry the insulation off cables, distort 1/2" thick busbars and fracture porcelain insulators. The key cause almost all times is poor electrical connections that have led to increased current draw that eventually results in overheating and further failure of the poor conection resulting in a system failure through disconnection of the poor connection or damage to other components.
Having looked only externally at the ptu units not internally like yourself I see many with corroded prongs or loose connectors,my thoughts are as above the possible rise in current caused by the poor connections is the reason for the internal failure due to heat build up. It would from my experience seem likely that a poor connection at the connector would initially cause misfire or non starting that may alert the owner to a problem and a cure (tighten connection or make good)However a slow build up of corrosion could over a period of time cause excess current draw on maybe one or two output`s only, slowly causing the internal soldering to fail? But also I thing there is a more likely chance that a poor connection to more than a couple of the outputs would lead to a rapid internal heat up due to overcurrent and this could happen in a matter of minutes and result in a fried ptu,this would explain how sudden unexpected failure can occur.In Ken`s case after the garage refitting the ptu I believe a poor connection was made as the spring clip was missing! then almost immediatly the damage was done.
When substituting my ptu for his the car started and ran perfectly,after reversing them it would not even start so the whole unit was damaged, again pointing to a single catastrophic failure in one go.
I suppose my point is this, if my theory is correct the corrosion of the terminals and security of the connectors is the main if not all causes of ptu failure with the damaged internal soldering the result not the cause, and checking this must then be added to the service schedule of all our car`s as a damage preventative measure? what do you think?
Jeff TT