I’ve now owned my 2005 (MY2006) 4200 CC for over three years and I still have an intermittent problem starting it from hot. This seems not to be an uncommon problem, but I have yet to find a definitive list of what to do to resolve it.
The car starts immediately from cold or when the engine is still warm, but sometimes (but only sometimes) it won’t restart when the engine is hot. It happens both in the winter and in the summer, and seems to be related to the engine temperature, not the outside temperature.
Returning home on the very day of my purchase (!!!) the car did not want to restart hot. I had stopped for 10 minutes in a service area (not to refuel, this having been done 65 miles previously.) When I wanted to restart (so after 10 minutes) the car did not want to restart. The starter motor spun the engine very quickly with no problem, but the engine refused to start. I left it for another quarter of an hour, and then it started as if nothing had happened.
Once home, plugging in a generic ODBII reader I had a pending P0128 code - "coolant temperature below thermostat regulating temperature". By doing research I found that this could come either from the thermostat, or from the coolant temperature sensor. The temperature indicated on the dashboard remains quite low, rarely exceeding 75°C, but this could come from false information provided by the sensor, which would result in too rich a mixture, and therefore the refusal to restart. From time to time the P0128 code has changed to "active" (therefore with the engine warning light coming on) without in itself creating a starting problem.
The car has not wanted to restart from hot from time to time ever since then, quite rarely and always shortly after stopping with a hot engine. After a few minutes it always restarts as if nothing had happened, albeit sometimes with a higher than normal tickover for a while. The car drives perfectly.
However, still only with the engine hot, I sometimes also had a problem when I reached circles slowing to a stop to yield to other traffic. Letting the system downshift on its own when approaching the circle, sometimes the engine has simply stalled, with the impossibility of restarting for 10 minutes / a quarter of an hour. That is to say that once stalled, I found myself with the problem of refusing to hot start without waiting. Doing some further research I found that stalling in these conditions could be the result of too low a "PIS" (the hot clutch slightly touching the flywheel causing the stall). Having bought a “Launch X431 Pros Mini” diagnostic tool a year ago, I increased the "PIS" to 5.2 and it has never stalled while driving since.
It had been months since the car refused restart when hot, but it did it to me again a few weeks ago, so I decided to have the coolant temperature sensor replaced. It has made no difference (temperature gauge still remains quite low, rarely exceeding 75°C, and still the occasional refusal to restart from hot.)
I also increased the PIS to 5.35 in case the clutch was still dragging when hot, but it has still done again it since.
During my three years of ownership, in addition to replacing the coolant temperature sensor, the battery, the clutch and the air filter, inter alia, have been replaced.
The last time it wouldn’t restart from hot I tried switching the ignition on and off several times before using the starter motor as I had read that the problem could come from a problem with fuel pressure not holding up (non-return valve not working) but that achieved nothing. There is no smell of gas under the hood. Opening and closing the gas cap makes no difference. Ditto the door. The brake light switch is working properly.
I am at my wits end… …all suggestions as to what to try next (and in what order) very welcome.
Thanks in advance
Tony
The car starts immediately from cold or when the engine is still warm, but sometimes (but only sometimes) it won’t restart when the engine is hot. It happens both in the winter and in the summer, and seems to be related to the engine temperature, not the outside temperature.
Returning home on the very day of my purchase (!!!) the car did not want to restart hot. I had stopped for 10 minutes in a service area (not to refuel, this having been done 65 miles previously.) When I wanted to restart (so after 10 minutes) the car did not want to restart. The starter motor spun the engine very quickly with no problem, but the engine refused to start. I left it for another quarter of an hour, and then it started as if nothing had happened.
Once home, plugging in a generic ODBII reader I had a pending P0128 code - "coolant temperature below thermostat regulating temperature". By doing research I found that this could come either from the thermostat, or from the coolant temperature sensor. The temperature indicated on the dashboard remains quite low, rarely exceeding 75°C, but this could come from false information provided by the sensor, which would result in too rich a mixture, and therefore the refusal to restart. From time to time the P0128 code has changed to "active" (therefore with the engine warning light coming on) without in itself creating a starting problem.
The car has not wanted to restart from hot from time to time ever since then, quite rarely and always shortly after stopping with a hot engine. After a few minutes it always restarts as if nothing had happened, albeit sometimes with a higher than normal tickover for a while. The car drives perfectly.
However, still only with the engine hot, I sometimes also had a problem when I reached circles slowing to a stop to yield to other traffic. Letting the system downshift on its own when approaching the circle, sometimes the engine has simply stalled, with the impossibility of restarting for 10 minutes / a quarter of an hour. That is to say that once stalled, I found myself with the problem of refusing to hot start without waiting. Doing some further research I found that stalling in these conditions could be the result of too low a "PIS" (the hot clutch slightly touching the flywheel causing the stall). Having bought a “Launch X431 Pros Mini” diagnostic tool a year ago, I increased the "PIS" to 5.2 and it has never stalled while driving since.
It had been months since the car refused restart when hot, but it did it to me again a few weeks ago, so I decided to have the coolant temperature sensor replaced. It has made no difference (temperature gauge still remains quite low, rarely exceeding 75°C, and still the occasional refusal to restart from hot.)
I also increased the PIS to 5.35 in case the clutch was still dragging when hot, but it has still done again it since.
During my three years of ownership, in addition to replacing the coolant temperature sensor, the battery, the clutch and the air filter, inter alia, have been replaced.
The last time it wouldn’t restart from hot I tried switching the ignition on and off several times before using the starter motor as I had read that the problem could come from a problem with fuel pressure not holding up (non-return valve not working) but that achieved nothing. There is no smell of gas under the hood. Opening and closing the gas cap makes no difference. Ditto the door. The brake light switch is working properly.
I am at my wits end… …all suggestions as to what to try next (and in what order) very welcome.
Thanks in advance
Tony
