Morning,

Wondering if someone might be able to shed some light on a problem I've seeing with my S3 XJ6 EFI.

The back story is that the cylinder head has been changed and the machine shop have not done a good job, new valves with old guides on one side and vice versa on the other. After a long high speed run, you shut down and restart after a few minutes there is blue smoke that clears after a few minutes. For the first time yesterday, it smoked on overrun down a hill (1/10 decent, approx 3000rpm in first gear). There is also a misfire just above tick over, that clears by 1200rpm as well - so there are some head issues!

The problem that concerned me yesterday was that the oil pressure warning light came on for a few seconds after slowing for a junction, then immediately came back up but was then fluctuating on the gauge by a few PSI. Whilst the light didn't come back on the gauge did drop below 40 PSI a two or three times, but this was all slow speed below 1500rpm. This isn't normal behaviour for my engine, that has always shown good oil pressure over the last 40k miles.

As the initial drop was measured by both the lamp and the gauge, I'm tending to think it's not an instrument issue, but also can't think it's tied to the head issues either?

Thanks in advance
Matt

 

1
1. Blue smoke as you ndescribe is a valve seal issue.

2. Swap in new sensors fr the OP. They tend to go bad. been there. done that.

Carl