Started back on this Monday by doing a gas test-all emissions OK.No coolant loss,leaks or overheating,but no 1 plug slightly lighter than other 3.I then tried introducing a misfire on another cylinder (lifting coil away from another cylinder).After about 2 mins of running like this ,the relevant cyl cut the injector and showed similar fault code,then immediately the code was cleared,injector came back on.So it seemed no 1 injector was being deliberately shut down by the ECU as it detected a misfire.
But was there a real misfire or not?I did a compression test to reveal (in PSI) 1/150 2/220 3/220 4/215.I'm not sure how the system can detect this,but decided that even though the car ran and idled fine, it was sensing misfire on no 1 then shutting down inj 1 to protect the cat as Mike and Shaun suggested.Can you tell me how it can detect that?
Took off the head and found burnt exhaust valve/seat on no 1.Carried out complete top end overhaul,reassembled and all comps now 220/230.
Left the car running for some time,no probs, then during extended road test,now misses sometimes on acceleration,but now no shut down of injectors. 2 codes ,16646 p0262 cyl 1 inj circuit-N30-high and 16652 p0268 cyl 3 inj circuit-N32-high.Car now idles fine,these symptoms/codes different from before!
These codes point to wiring short to injectors,so i've stripped out the loom section from injectors to ECU.Not had time to test each wire but all looks OK.Temporarily refitted loom so i can run around in it the weekend,and so far no fault!
Any help please-in for about 25hrs plus so far!
Colin.