'01 A4's been running like a dream recently, with the exception of a minor occasional misfire. Swapped plugs in the misfiring cylinder, and the misfire moved with the plug. So this morning I changed out all 4 plugs for brand new OEM ones. Right after changing all 4 plugs, I started the engine and it idled smooth as silk. I turned it back off and went back in the house to get my gear ready for the day's outing.

When I came back out 30 minutes later, the car would no longer start. It doesn't turn over or do anything. The starter does not engage. Everything lights up normally as it should, all sounds are normal, and battery voltage is optimal. Turning the key to start the engine just accomplishes nothing. I definitely have the clutch all the way to the floor when I try to start it, it just doesn't work.

Checked with my VAG-COM, and there are no codes stored in any modules. Everything looks clean. Can't even begin to guess what's wrong or what to look for. It's too weird a coincidence that this is happening right after I changed all the spark plugs, but the engine definitely started and ran immediately after I put in the new plugs.

I hope someone can help me figure this out. Right now my car is a dead weight in my driveway.

 

See if you can pop-start it. That'll at least rule out the starting circuit or the fuel/timing systems, one way or another.

 

Wish there was some kind of incline around here, or someone to help me push I'll try it in the morning

 

push it yourself seriously tho. i had to pop start my car for a month, not too hard. Pop starting is going to eliminate a lot. Also check fuses and relays if you have time.

 

Quick question for clarification:

When I turn the key, the info center tells me to press the clutch all the way in before starting the engine (which is as expected).

So when is this message supposed to disappear? When I press the clutch all the way in, or when the engine starts?

 

when it starts

 

darn, there goes an easy way to diagnose the clutch safety switch...

 

ok... weird. I pressed the diagnostic button in the dash cluster, and the info center displayed the typical "OK". When I tried to start the car after that, it turned over and caught right away as if nothing at all was wrong. Now it seems to start every time.

I'm guessing this is probably yet another very random coincidence (like the new spark plugs "causing" this problem in the first place). Most likely the real problem lies in either the clutch safety switch or the starter relay. I forgot to mention before that the starter relay never clicked when I tried starting it yesterday. I suppose that at 225,000+ miles, things like that might be starting to wear out. I wish there was an easy way to determine which component is going bad.

(there is a starter relay in these, isn't there? I can't spot it in the wiring diagram)

 

Think about the ignition switch behind the lock cylinder. It's a known weak spot on B5's, and it all starts there. The plug change and pushing the diagnositc button might both just be coincidential. I swapped mine last winter. It's only $20-30, and takes about half hour to do.

 

hmm, good call, didn't even consider that