Overfuelling at Start-up?

[yknot]

Have spent some time investigating the apparently common problem of overfuelling at startup (seems more prevalent with the S3c's) and the associated misfire/dead spot when pressing the gas pedal with a cold engine! As it only lasts a short time, many have simply allowed their engines to warm up before taking to the road, however there may be a solution!!

There are lots of topics on the S forum with the same issues but this post from the Chim forum appears to show similar symptoms with the Lucas 14CUX ECU (although I didn't have this problem on mine) and is an interesting suggested fix!

https://www.pistonheads.com/gassing/topic.asp?t=14...

Anyone tried it with our EEC-IV system?? It would certainly 'fool' the ECU into seeing a higher engine coolant temperature reading and thereby set a leaner fuelling map but is this viable with the L-Jetronics system??

[Penelope Stopit]

How about this method with a timer if needed?
Ignore the Ohm ratings as this diagram was created for a Griffith

[GreenV8S]

yknot said:

this post from the Chim forum appears to show similar symptoms with the Lucas 14CUX ECU (although I didn't have this problem on mine) and is an interesting suggested fix!

I've never had those problems on mine and hacking the coolant temp sensor is not a bodge I'd recommend. I also don't agree with the OP's comments on that thread about spark plugs. The hotwire ECU is mass produced and designed to be user friendly and robust. I drove it 150K plus miles in all weather with the commonly recommended B7ECS plugs without any of those problems. To Be fair I was also using the correct combination of extenders and leads so other people with the wrong resistance rated parts could run into running problems I didn't see. However, it seems to me that thread is recommended a bodge to workaround some other fault they haven't recognised yet.

I suspect the same may be true of the S3. It's a standard mass produced engine and EFI system and it seems unlikely that Ford would have got the fuelling so wrong.