Year of Manufacture *: 2005 (55) Engine Size and Code *: Z14XEP ( Optional ) Scanner Used: Various inc Tech2
Customer reported poor running. Fault codes recorded for lambda sensor heater circuits Cam sensor P0340 among others. As I was getting multiple sensor faults I have had ECU problems in the past giving these symptoms so I sent the ECU to Ecu Testing. When returned I could clear all codes except the P0340. Deeper investigation showed the cams were incorrectly timed (i.e. on the incorrect crank timing detent). I re-timed the engine expecting an end to the problems, no chance, the engine still hunts at idle. Questioning the customer, they said they had only had the car a couple of weeks before bringing it to me so I have no history. So far I can see newish lambda sensors, MAF, CMP and a broken cam cover bolt as well as the mis-timing issue. I have smoke tested with no leaks found (I suspected a sticking EGR valve) which I eventually removed to physically check it, no problems found with it. I removed the upstream lambda sensor, checked the cat had not collapsed and ran the engine with the sensor out in case the exhaust was blocked. The ECU software has been updated to the latest issue. All this made absolutely no difference to the hunting. The compressions were measured at 190, 195, 195, 200 psi. At idle the the manifold vacuum is poor at 56 kPa and I suspect this is why it hunts, what I can't find is the reason why. To me this would point to the cam timing but I have re-done it several times. Another possibility could be sticky valves as I'm led to believe that is a common problem, but would it give these symptoms? Could it be wrong oil grade affecting the hydraulic tappets? Any ideas? Shaun
as the valve timing was out & the vac is low have you considered poorly seated valves (slightly bent) a cylinder leakage test would probably be my next test. alternatively has it had a second hand head & not the correct cams? broken valve springs?
Hi Steve, bent valves are a possibility although it did run and drive reasonably well with the timing out and no nasty noises. My concern is why the timing has been adjusted at all? At 54000 miles I suspect it's not timing chain wear. I was worried that maybe the car has been into deep water and had a new head that perhaps is incorrect. There was a significant amount of rust on the cams in places too. I wish I'd never seen this car tbh. I hate sorting out other people's messes. Shaun.
Hi Andy, Despite it hunting away at idle the system goes into closed loop and stays there. From memory STFT stays around 0 and LTFT hunts around +/-4 for idle, at 2000rpm they both steadied around 0, sorry didn't write the values on my notes. Can't remember what the rear O2 was doing. Took loads of notes, did not unfortunately write everything down. The customer has taken the car for the moment and is going to report back.
is the new MAF a factory one or some chingalong shit ??
Unresolved #
Posted by Shaun Dale on December 8, 2016, 3:21 pm, in reply to "Re: Vauxhall Tigra hunting at idle." Edited by board administrator December 9, 2016, 1:13 pm
Customer has not been back to me. I have seen it from time to time driving around so they are either putting up with it or it has settled down.
on June 8, 2016, 10:23 pm, in reply to "