XJ6 series 3 stalls on throttle blip when cold
#1
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So,
I've searched and find lots of issues a bit like mine, but none that are the same.
Series 3 starts beautifuly; no throttle needed. Idles sweet and low. But if I poke the throttle before it's reached 75 F it stalls and wants to die. Give it a steady push and it'll rev beautifully while still cold. Poke it quickly just after that rev and it'll stall and want to die. these are both repeatable as much as desired until it warms up. Once it hits 75 F you can do whatever you want and it'll never do anything unusual.
This sounds like something specific is happening. Only I don't know what is active at startup and until the engine reaches 75 F. Anyone have a clue I can borrow?
Thanks,
Paul
I've searched and find lots of issues a bit like mine, but none that are the same.
Series 3 starts beautifuly; no throttle needed. Idles sweet and low. But if I poke the throttle before it's reached 75 F it stalls and wants to die. Give it a steady push and it'll rev beautifully while still cold. Poke it quickly just after that rev and it'll stall and want to die. these are both repeatable as much as desired until it warms up. Once it hits 75 F you can do whatever you want and it'll never do anything unusual.
This sounds like something specific is happening. Only I don't know what is active at startup and until the engine reaches 75 F. Anyone have a clue I can borrow?
Thanks,
Paul
#2
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#3
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Coolant temperature and air mass flow are the two big inputs to the EFI, the other things like ambient temperature etc are just trims.
As it works OK when hot, it does sound to me like the coolant temperature is not being transmitted correctly to the EFI box. This could be a defective temperature transmitter. Only way to find out is to swap with a known good one, as there are no diagnostics on this early EFI system. You can always check the existing transmitter by checking the resistance when cold and when hot, but I don't know the values.
As it works OK when hot, it does sound to me like the coolant temperature is not being transmitted correctly to the EFI box. This could be a defective temperature transmitter. Only way to find out is to swap with a known good one, as there are no diagnostics on this early EFI system. You can always check the existing transmitter by checking the resistance when cold and when hot, but I don't know the values.
#4
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#7
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