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 would first suspect the coolant temp sensor...which controls cold engine fueling. Can be tested if you have a DVOM. Or, not painful if you just wanna replace it as a guess...about $20 and 10 minutes labor


Cheers
DD

 

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.

 

This shows the resistance values for the CTS

Testing the Coolant Temp Sensor

Cheers
DD

 

Thanks to everyone that replied! I'll test the coolant sensor and post my results.

 

So, the CTS was functioning but not correctly. A new unit resolved this issue completely. Now it revs nicely even when cold.

Thanks!
Paul

 

Nice to know I was right !! Hope car goes well, and you get lots of enjoyment out of it.