DKloth

My 2007 S4 Cab is experiencing a starting problem. It had never been a problem in the past, but now, on several occasions, it cranks as it always has, but it won't catch. It has plenty of power from the battery, and the starter is turning the engine over just fine, but it won't start. My limited knowledge and experience tells me that it's either not getting fuel, or it's not getting spark.

The only thing that has changed recently is I replaced the sparkplugs and coils. While it's possible that the starting problem occurring so soon after new plugs and coils is a coincidence. If it is, it's a strong one.

When I had the car checked by my mechanic, the same guy who replaced the plugs and coils, there were no fault codes. He couldn't find any problems of any kind.

Does anybody have an idea? Anybody experience something similar?

Warhead

does the rpm needle "bounce" while starting?

DKloth

Thanks for responding. I delayed my comments to check the tach. Also, at present the car is starting. Who knows when it will fail to start again.
As for the tach needle bouncing, or moving at all, it doesn't move at all until the car starts. By that I mean during that small amount of time while the starter cranks the engine before it catches, the needle just lays there, peaceful as can be. As soon as the engine fires, boom, the needle jumps to whatever the RPM is.

DKloth

Not many of you guys are following this thread, but I found the starting problem and had it repaired. It was a faulty Crank Position Sensor. I didn't even know it HAD a Crank Position Sensor. In any case, it's fixed, now.

Warhead

Sorry I ment to reply.

If the needle doesn't move at all while cranking. it can be an indication the your crank position sensor is bad. since the CPS uses a magnetic field it should generate small movements in your tach while cranking.

Glad you go it fixed!