ST200 Fast Idle issue – Solved!

So another big issue solved on the 200. Since buying her the idle speed has been sticking at 1500-2000 from start up. From doing some research we came up with two potential problems that could be the culprit – a split in the front breather pipe or a fix needed on the Air intake bypass pipe.

Breather pipe fix.

This one was simple, the pipe was half hiding under the plastic engine cover but after three bolts this was off and the pipe was replaced. Just pulled off from both ends, and the new one was replaced in moments. The original pipe had a number of splits and was clearing letting air by.

So, had this done the trick? Well no. Idle was still really bad so it was on to part two of the possible fixes!

The fast Idle fix – Restrictor in the Filter Bypass

Probably should have gone straight to this! Turns out that there is a pretty common issue with the 2.5 Litre Duratec. The idle can often be affected due to excess air in the filter bypass pipe, and this can be solved by fitting  copper stop end into the pipe with a 4.5mm hole drilled through in it. This restricts the air and in turn brings the idle down, and being a bypass it does not reduce overall engine power.

Once slipped into place we fired her up again and took her for a run…..success! Still a tad haigh at 1000-1100, but the revs drop off nicely when changing gear or in neutral. So another major issue resolved.


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