Hot start problem
Discussion
I`ve just replaced the engine/gbox on my S1 after a major overhaul it starts and runs fine but if I stop it for while it wont start again unless I keep the starter going & going & going etc I had the problem previous to the overhaul so I`m fairly sure its not to do with that,can any of you guys help me?
carsgrafter said:
I`ve just replaced the engine/gbox on my S1 after a major overhaul it starts and runs fine but if I stop it for while it wont start again unless I keep the starter going & going & going etc I had the problem previous to the overhaul so I`m fairly sure its not to do with that,can any of you guys help me?
This is another one of those quirks that several people have commented on in the past, mine does it to a certain extent but not badly and IIRC Chris Wildfire does to a lesser extent too.
Possibly, that when the engine is hot the ECU is over compensating and making the mixture too lean.
Another theory is that the underbonnet temp is higher and fuel vapourises in the fuel rail and is therefore not available immediately when you turn the engine over.
If you find out, can you please post?
TIA
>> Edited by KentishS2 on Monday 21st February 08:34
So do you have to floor the pedal to start it when warm ? Is it then lumpy for a while? what happens at the exhaust?
I would have thought that any evaporation would be overcome by a new supply from the pump in moments.
(Thankfully don't have this problem.)Different sensors/ECU arrangement on S1 though I think.
I would have thought that any evaporation would be overcome by a new supply from the pump in moments.
(Thankfully don't have this problem.)Different sensors/ECU arrangement on S1 though I think.
I occasionaly get the same problem on the S1 if only left 1 - 2 hours between stop and start. I think is it something to do with the sensor in the K-tronic injection system getting the mixture wrong when the engine is neither hot (just run) or cold. This is a very basic system and does not have a real ECU brain. The S bible has a decent section on this topic and suggested cures if I remember correctly.
The 2.9 S's use a different injection system L-tronic I think so operate differently and have a more sophisticated ECU.
The 2.9 S's use a different injection system L-tronic I think so operate differently and have a more sophisticated ECU.
The K Jetronic fuel injection on the 2.8 is all mechanical with no electronics which is simpler and usually more reliable. (No throttle pots)
Compare a 2.8 with a 2.9 and there is far less plumbing on the 2.8.
On the 2.8 there is a cold start system which richens the mixture while cold.
This is controlled by the Thermotime switch.
When the engine is warm, it prevents the fuel start valve over riching the fuel mixture.
It can get confused if rushed.
I have had problems when the engine has been running for a few miniutes at tickover and when I have wanted to drive away the engine has nearly cut out through too much fuel.
When starting keep your foot OFF the accelerator until the engine fires then catch it on the accelarator.
It sounds nice this way.
When the engine is already hot only bring the revs up steadily for the first time after starting.
The 2.8 is brain dead, its system does cope with fast changes.
Once your engine is warmed up and running then it is very free revving.
They are not much good below 3000 rpm and needs to be pushed through the rev range up to 5000 and the sound is pure symphony.
The 2.9 has more lowdown torque and needs differant treatment.
Both are great but need to be treated differantly.
Compare a 2.8 with a 2.9 and there is far less plumbing on the 2.8.
On the 2.8 there is a cold start system which richens the mixture while cold.
This is controlled by the Thermotime switch.
When the engine is warm, it prevents the fuel start valve over riching the fuel mixture.
It can get confused if rushed.
I have had problems when the engine has been running for a few miniutes at tickover and when I have wanted to drive away the engine has nearly cut out through too much fuel.
When starting keep your foot OFF the accelerator until the engine fires then catch it on the accelarator.
It sounds nice this way.
When the engine is already hot only bring the revs up steadily for the first time after starting.
The 2.8 is brain dead, its system does cope with fast changes.
Once your engine is warmed up and running then it is very free revving.
They are not much good below 3000 rpm and needs to be pushed through the rev range up to 5000 and the sound is pure symphony.
The 2.9 has more lowdown torque and needs differant treatment.
Both are great but need to be treated differantly.
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