VCT EX_VALVE values

[ChrisM41]

Im trying to diagnose a hesitation my 2005 Focus 1.6 has. There is nothing (apparantly) wrong with the ignition system or fuelling so ive moved on to the VCT system.

The car is quiet, there is no diesel noise at start up so think the variators are OK, but I do wonder if the VCT solenoids are a bit dodgy, specifically the exhaust one. At idle the EX_VALVE values as read by OBD are stable, at 0, but if I hold the revs at, say 2000rpm they vary quite a bit, from 4deg to 20+, and im wondering if that may result in the stutter. At higher revs the values are quite stable again, the variance is at its most extreme at 2500 and under, which is when the car is stuttery.

 

I have had the cam slow response OBD error a few times randomly as well, but it goes away at restart. Ive changed the oil and used a flush but it didnt help.

[ChrisM41]

To answer my own question, no the values shouldn't jump around at low speed. I replaced the VCT solenoid with a later model from a 2011 car (which is compatible, but clearly revised), and the variance is now smooth. The car also runs smoother and the exhaust note is less harsh.