S1 - not running smoothly

[EdT]

Went on first decent length trip after the S1's top end re-build. All good apart from I noticed whilst at constant revs, the engine's not running totally smoothly, and the car shudders a little (makes it sound maybe more severe than actually is!). Any initial pointers to look into?

[MJG280]

spark plug or lead damaged Check colour of all plugs. Even if it isn't that it may give a pointer to the area with the problem.

Other one is sticking valve. I cured that with an oil flusher.

[jim2607]

I would definitely check the fuel pressure is correct as it makes a massive difference. Should be about 78 psi before the fuel distributor! The S1 Capri engine being K-Jetronic is super sensitive to correct fuel pressure and if the fuel pump isnt up to scratch or the warm up regulator is a little clogged it can make a lot of difference to how it runs. Ive been going through all this on my S1 recently as it hasnt been running right. Just an idea!

[EdT]

A pal suggested some sort of tune should be done after a top end re-build.... no idea what can be done with injection engine, maybe the fuel/air mix as a start?

Edited by EdT on Wednesday 14th July 13:38

[EdT]

Well, 4 hours with my local mechanic & it's all sorted. Fully de-niggled. We expected it'd need a bit of professional hands on, after the rebuild. Feels like a new car. Just did 50 fun miles & I'm deaf