'96 Jetta 3 (1.6 CSL) Not Starting
 

Hi, I am just about at my wits end, and hope someone here can assist.

I have a 1996 Jetta 3 (1.6 CSL), low mileage.

Recently, the car started occasionally refusing to start after running to the shop or school, and it would need to sit for a few minutes before it would fire up again. Predictably, the day came soon after where it simply refused to start at all. Having had this problem a few years back, I bought a new BREMI coil (I replaced it previously with a second-hand coil, so did not think it strange that an old coil was dead).

After fitting the coil, the car still did not start. I proceeded to get the multimeter out and found the Number 1 HT lead showed no resistance, so proceeded to buy new HT leads and new spark plugs, as they were due for a replacement anyway, and fitted them. The car started, I drove it to the shops and to the fuel station. switching off and starting at least three times in the process. No issues, no stalls, the car ran normally.

The following morning, the car refused to start. It turns over fine, but does not fire.

I have inspected the distributor cap, but there is nothing out of place - no moisture, no corrosion, nothing odd. The fact the car started and ran normally tells me there is nothing wrong with the fuel system. Every check I can think of (including spark checks etc) is good. The car just refuses to fire up.

Please, please help.

Update
 

Okay. So things have gone from frustrating to weird.

I replaced the fuel pump relay as I figured out there was no fuel reaching the manifold (main hose from rear) when I tried to crank it over. No dice, its still not starting.

I decided to do another spark test, and now suddenly there is no spark whatsoever, not from the coil, not at the spark plug.

So this starts to sound more and more like an immobiliser issue to me...replaced the battery in the immobiliser fob thing, which we haven't needed to use for 5 years or more, and tried again. Still no dice. Came back to the car a while later and it was locking and unlocking itself non-stop, key still in the ignition. Disabled the alarm with the key fob, and it stopped. Tried to start it, it sort of sounded like it wanted to start but then made some weird backfiring noises.

Weird constant beep/buzz sound from around the inlet manifold. Any advice?

Solved
 

Immobiliser issue. Solved by auto-electrician.