AFR weak on cold days
 

Guys,

I have a Porsche 993 driver with a supercharger on it. Not pushing anywhere near as much power as some but as I've used this site for information so many times I have a question that I hope someone might be able to help me out on. Car runs fine in warm weather O2s around 800 with a 50:50 mix of methanol/distilled water injection based on a souped up 1S system. I have a pre-race pump priming pump and a 2 stage injection system. When it gets cooler say below 10C the AFR soars off the scale (weak). I'm not sure if it is a side effect of the methanol/water injection and to be expected or its a real issue. Car runs fine but the AFR tells me something is amiss. Tried lots of things, temperature sensor, fuel pressure, all spot on. So i'm left with this being a side effect of the methanol injection or the Air flow meter. So my question really is would injecting alcohol on a cold day cause the O2 reading to read way to weak when in fact it is ok?

Many thanks for any help you can be, Mark.

Have you seen this?

Maybe something in common.

Good luck.

Thanks Puntorex,

it just could be. I'll try the car with just distilled water and see if I get a change in its behavour.

I'll post if I see a change. Now got to use the methanol up over the next week or so. :-) before I can refill with distilled water. So it could be a week or so before I know there has been a change.

Cheers, Mark.