Carrera 3.2 Starting Issue
 

Having a really strange issue that’s cropped up recently. Starting the car from cold yields no issues, ever. Runs perfect. If I turn off the car and wait 5 minutes, it starts back up immediately, and again runs perfectly.

However, if I wait approx. 20 minutes, the car will crank but not turn over. Waiting a bit longer (an hour) will give me an immediate start and no issues.

I thought it might be one of the following three things:
- DME relay
- Speed Sensor
- Reference Sensor
- Battery

But all three were replaced just 2 years ago. Only other thing I can think of is CHT sensor, but I’m grasping at straws. Any ideas?

Coils can act this way.

x2. Had a similar problem on my old 944. New coil was the answer.

If you search pelican there are some threads about testing resistance of the coil. I am having a similar issue with my e36. It always starts but when a little warm is a little hard to start. Am going to test the coil to see if it might be the culprit.

I had the problem where the coil would lose continuity because of heat expansion. When it cooled, it would regain contact in the coil wire that was failing.

easy method of checking a coil: when the engine will not start: unplug a spark plug wire at the distributor. Insert a spark plug. ground the plug. have someone crank the engine several evolutions while you observe the COLOR of the spark at the business end of the plug.

if color is anthing other than blue, replace the coil.

My ex-SC went through a couple of pricey "aftermarket" coils. After the 2nd tow my mechanic handed me an old school oil filled Pertronix Flame Thrower. I heard all of the resistance mumbo jumbo and while it's pertinent, being left on the side of the road made me more aware of how simple the fix can be.

My '74 uses an MSD and MSD coil with Clewett wires. They aren't universally loved but they do work. Long term plan is to do away with the distributor all together and go crank fired. It's not a stock 2.7 ;)