Normally my car starts and runs beautifully, but only twice - once in October and once this morning - it failed to start right up. Here's what happened those two times.

The car started briefly, but didn't sound "right" and died almost immediately. Upon cranking it the second time, it cranked for quite a while and wasn't firing at all. Finally, after cranking it for what seemed like 5 minutes (but was probably more like 30-45 seconds) it fired up - first missing a bit but then running perfectly again. Over a period of 4 months and about 4000 miles as a daily driver - usually being started about 5 times a day - there have been no other starting or running issues - no OBDII codes.

Any guesses as to whether this is a warning sign of something going wrong, or should I just ignore it until a problem becomes more obvious.

On my MGB, with the lack of electronics & computers, I'd assume it was an ignition or fuel delivery fault. On the XJ6 I'm not so sure. My first thought was that it might be a fuel pump beginning to fail - but my experience with those failures on the MG was that the problem quickly got more frequent and more serious. If it were ignition related, it would also seem unusual to be so infrequent since those parts tend to either work or not work and don't repair themselves.

It seems unusual that the same exact fault occurred both times under almost exactly the same circumstance - cold starting after sitting unused for a couple of days. Weather doesn't seem to be the issue since the first time was in warm weather and the car was garaged, this time it's cold (30's F) and the car was outdoors.

 

Something that intermittant can be hard to track down, obviously.

At the time of the two events did you happen to notice if the tachometer moved at all while cranking? It should register a couple hundred RPM. If it doesn't, the crankshaft position sensor is probably on the blink.

If you don't wanna wait for a repeat event and are up for a guess I'd go with the crankshaft sensor. Of course, you might have to wait months to know if you got lucky or not :-)

Cheers
DD

 

Didn't notice what the tach was doing at the time. I'll watch for that if it does it again. Thanks for the tip!