Hi, My compression tester was messed up by someone who tried to use it on a diesel. On other cars I have used it as an indicator to make sure cylinders are within 10% but the absolute compression was always too much as the needle no longer sit on 0psi now it sits on 50psi. Other cars have been low compression turbo builds and it has been fine as an indicator and I would take off 50psi of the measurement. However I have just done a compression test on a 2.0 petrol 2008 and it was just shy of 300psi so take 50 off then 250psi that surely is too much or maybe my gauge is not linear in respect to as compression goes up it over reads more. What are the correct figures for this engine, might need to buy a new gauge.

 

I would definitely buy a new gauge

Will do they were all within 10pc do you know that source of what the psi should be out of interest? Tks

250psi is about right for this engine.  (Same as ST150 Fiesta).

Though I agree with Dave that you should replace that tester if you need to do any accurate testing.

Ah thanks for confirming specs. Ordered a new one.