Hi All I have taken my Z off the road for the winter, it has been stored outside undercover. I attempted to start it today after many weeks and it has developed a problem. It starts ok but the rev counter fluctuates between 500rpm to 1000rpm on idling and it seems to be a regular fluctuation every second or so. I have tried to rev it up a little just to see what happens but it struggles to get to 2000rpm. I have checked the distributors with my meter and they all seem ok. Also and I don't know if this is relevant or not but I have noticed some fumes coming from whatever is directly below the side of the engine where the spark plugs are situated, again I don't know if this relevant or not. Anyone got any ideas before I potentially start running up some expensive garage bills. Many thanks
Engine mis firing
- Thread starter Robert63
- Start date
First of all, it would help to know model and engine.
Second, it's always prudent to utilise a scan tool of some sort if you have one, so that any error codes can be indicated and you can relay them here to help diagnose the problem.
The fumes may well be oil which has leaked onto the exhaust manifold during storage. The cam cover gaskets can start to fail and produce leaks if not replaced.
The 'mis fire' you describe sounds more like rough idling and could be anything from a dirty/failing idle control valve, to a failing throttlebody, to a failed/failing coil(s) or spark plug(s), fuel pump/filter, etc. etc.
I would suggest as a first course of action getting hold of a scan tool and see what codes come up before specualting on the root cause.
Good luck!
Second, it's always prudent to utilise a scan tool of some sort if you have one, so that any error codes can be indicated and you can relay them here to help diagnose the problem.
The fumes may well be oil which has leaked onto the exhaust manifold during storage. The cam cover gaskets can start to fail and produce leaks if not replaced.
The 'mis fire' you describe sounds more like rough idling and could be anything from a dirty/failing idle control valve, to a failing throttlebody, to a failed/failing coil(s) or spark plug(s), fuel pump/filter, etc. etc.
I would suggest as a first course of action getting hold of a scan tool and see what codes come up before specualting on the root cause.
Good luck!
So the M54 engine.
Have a feel around the back of the engine block where the cam cover meets the top of the block. If you pull your fingers out from between the heat shield and block and they're covered in oil then your gasket is leaking. Replace it.
Indicate where you are located and maybe an obliging forum member in your area may be able to assist with scanning.
Have a feel around the back of the engine block where the cam cover meets the top of the block. If you pull your fingers out from between the heat shield and block and they're covered in oil then your gasket is leaking. Replace it.
Indicate where you are located and maybe an obliging forum member in your area may be able to assist with scanning.
Zed shed Cymru run between members of this cc and other forums is centred around Gwent area Newport so not that far from you we can scan cars diagnostics and smoke test the inlet system and engine when we have a get together or one of us has problems to sort.
Sounds like the Maf at fault, you could try cleaning it with Maf Cleaner Spray. If you disconnect the electric plug on the Maf the car will run in default settings, do that and see if it makes a difference. If it improves, then consider replacing the Maf with an oem replacement, avoid cheap pattern parts.
I have replaced the Mass air Inlet boot as this had a rip in it. I have cleaned out the air filter and cleaned the MAF device with MAF cleaner. I have noticed that there is a flexible pipe that connects to a rigid pipe to the right of the + battery terminal on the engine bulkhead. This pipe is flat in two places could this be the problem possibly ???
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You may well have found the source of your problem!
Ofc any flex hose needs to be open and not flat in order to operate efficiently.
Anyway you can brace it open at where it’s flat, with a clamp or something, then trying to run the engine in order to cancel it out as the issue?
It sounds like it’s worth replacing in any case.
Cleaning your maf also doesn’t guarantee it’s going to work again if thats the issue.
Try unplugging the electrical connector for the maf then starting to see if that makes a difference. It wont do any damage.
Ofc any flex hose needs to be open and not flat in order to operate efficiently.
Anyway you can brace it open at where it’s flat, with a clamp or something, then trying to run the engine in order to cancel it out as the issue?
It sounds like it’s worth replacing in any case.
Cleaning your maf also doesn’t guarantee it’s going to work again if thats the issue.
Try unplugging the electrical connector for the maf then starting to see if that makes a difference. It wont do any damage.
