WEBER cold start question

[ThomasWilkinson]

Hello,

The colder weather [40-28F] (relative to normal Oregon weather anyway) has arrived.
I've got 40IDTs on my 2.5 9.8:1 914-6 motor.
The factory fire starter fuel enrichment system has been removed.
I have a question regarding two starting techniques.
Depress the pedal 2-3 times and turn over the motor.
Usually takes a second try to get it running in cold weather.
Once the motor is running:
#1 continue to modulate the throttle to get a stable running condition (which is activating the accelerator pumps) using a light foot. This has the motor showing ~1200-1600rpm.
#2 Use a slightly heavier foot and run the motor up to ~2000 or so rpms until she stablilizes (~15-30 seconds).
The first method is perhaps dumping more raw fuel into the motor, the second is running the motor harder when stone cold.
Am I splitting hairs here or is one method prefered?

TIA

TW
R Gruppe #130

[LeafGreen]

If you take the accel. pump out of the picture, I would say there is little difference between running the engine cold at 1600 RPM VS. 2000 RPM. So, I think your point about not dumping bucket loads of extra fuel makes sense. I would prefer to run as low an RPM as possible without feathering the throttle - and it sounds like you already found that RPM.

[ThomasWilkinson]

Alex,

Thank you for your input.
Makes sense to me.
I figured that the extra rpms used in the second technique would be less harsh than potentially washing down the cylinders with all that gas just to maintain a slightly lower initial rpm.
It would have been interesting to compare the current set up to the OE
"fire starter" enrichment (which may have actually dumped more fuel in than feathering the throttle- removed before I purchased the car).
I must say she runs pretty good once past the start up phase and will pull with hardly any protest in short order [better than several other Weber 911s I've driven].

Tom Wilkinson
R Gruppe #130
1970 914-6 2.5LS
1973 911 2.7RS spec.

[GreenT]

I've got Webers on a 2.2 with about the same compression as you. I've had it about 15 years, so we know what each other likes pretty well by now. I do exactly what you describe in #1. From a cold start I modulate the pedal for about ten seconds to keep it running. Then I can hold the pedal steady, and after about 20 seconds I can hear the rpm's start to rise when I am still holding the pedal at the same position. Then I know it's awake. A couple of blips to 2000-2500, and I can back out of the garage without stalling. I always try to get it running on the road under load as soon as possible, instead of letting it idle to get warmer. I try to keep it between 3000-3500 rpm until I see the temp needle start to come up. Since California now tops out at 91.5 octane for gas, I blend a gallon or so of 110 octane leaded race fuel with each tankful. Makes a big difference on those cold starts, fires first time every time, and no stalling when cold.