ok guys iv got a ford focus 18tdci with customer complaining of taking too long to start and needing a few tries to start when he comes to it in the morning (not every morning tho) he seems to think its worse when cold .to start with iv carried out a code scan and found p0234 relating to boost pressure control and p0191 fuel pressure circuit range/performance which i explained could be related to the problem and would be a good idea to look at . after checking and replacing glow plugs as 2 were found to be faulty and clearing codes the car was left with me so i could try a cold start with fuel presure, crank and cam all scoped to see what was happening needless to say on two mornings and a number of starts throughout the day the car started fine at this point the car was collected as customer wanted car back after me explainig that i had not seen the non start and really needed to keep it longer .
Next morning suprise no start customer calls for me to collect and once back in workshop car starts first time and has no codes stored hooks scope up to fuel pressure/crank sensor and cam sensor tries a number of restarts after around 4-5 starts i get the non start with crank and cam signals good but only getting around 0.6 volts fuel pressure and another occasion 1.1 volts at most which from examining other start ups around 1.2-1.3 is needed to trigger injectors so low fuel pressure possibly the cause
after leaving car set up next morning i try a start up again and all is fine again after a few restarts maybe a dozen i get a non start this time fuel pressure gets to 1.2-1.3 at which point injectors start to trigger and car tries to fire but fails as fuel presure sores to around 3 volts and again no more injector pulse, although both times this has failed to start it has not stored any codes, so far its looking like fuel pressure but what would cause it to first not produce enough and then produce too much.is it possible the IMV can stick i have since scoped the imv but the car has started everytime i am so far thinking the imv is faulty whats your thoughts may i add the car drives well and perfomance is fine with no other apparent issues i have some scope patterns i will add when i get a minute

many thanks lee