Cold start troubles, I daily drive mine so I need to get this sorted Options

[Neil914]

So I'll try to cover this neatly. I have a '73 2.0 with fuel injection
My 914 does not start cold with the starter motor. Every morning I roll it backwards out of the driveway backwards and then give it a running push down the gentle slope of my street. It will start cold no problem if you bump start it and get the engine turning over at 1,500 or 2,000 rpm. When I cranked the car over for a while I the engine would get flooded and smell of fuel, and then backfire significantly when bump started. Replacing the head temp sensor has helped that, but did not fix the whole problem. The Auxiliary air valve is dodgy and the car often idles high, but plugged or left open it makes no difference. The car used to start great cold and the problem has actually been gradual. When warm the car starts flawlessly. For the first couple minutes of running when cold the engine can die at idle due to the use of the brakes or headlights, presumably because this drops the voltage. I have tried jumper cables from another car to make sure I have plenty of volts but it still doesn't go.
Ideas?
Thanks

[JeffBowlsby]

Transmission ground strap, battery ground and power cable clean?
Ignition timing and valve adjustment?
Dirty spark plugs?
Cap & rotor?
Dirty injectors incl the cold start injector?
Trigger points clean and working?
Fuel pressure?

[dr914@autoatlanta.com]

I agree with Jeff, I would start with a valve adjust and tuneup setting the dwell and timing. internal combustion engines just start better when warm even if they have a problem, that problem always surfaces when the engine is cold.
If the car is flooding, you definitely have an ignition problem, since you replaced the head temp sensor. (I would check the resistance should be 2750 at 40 degrees. Also the cold start valve works at 40 degrees and colder, if you have a weak dirty out of adjustment ignition system and it is 40 or colder, maybe the cold start valve is injecting fuel that can not be fired off until rolling the car

So I'll try to cover this neatly. I have a '73 2.0 with fuel injection
My 914 does not start cold with the starter motor. Every morning I roll it backwards out of the driveway backwards and then give it a running push down the gentle slope of my street. It will start cold no problem if you bump start it and get the engine turning over at 1,500 or 2,000 rpm. When I cranked the car over for a while I the engine would get flooded and smell of fuel, and then backfire significantly when bump started. Replacing the head temp sensor has helped that, but did not fix the whole problem. The Auxiliary air valve is dodgy and the car often idles high, but plugged or left open it makes no difference. The car used to start great cold and the problem has actually been gradual. When warm the car starts flawlessly. For the first couple minutes of running when cold the engine can die at idle due to the use of the brakes or headlights, presumably because this drops the voltage. I have tried jumper cables from another car to make sure I have plenty of volts but it still doesn't go.
Ideas?
Thanks

[Neil914]

What might the problem with my cap and rotor?

[Neil914]

What does the backfire I am getting during a bump start explain?

[iankarr]

What might the problem with my cap and rotor?

If ithe cap or rotor are getting tired and worn, you’ll probably see that more when you cold start the car. I think Jeff gave you a great checklist. The ground strap and battery cable sound like they’re at least part of the problem, given the power shortage even with jumpers. One other thought....is the starter turning over strong? Is it possible that it’s too weak to spin the motor enough when cold?