Rover 416GSi 1990 misfiring after storage

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guynosborne
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Joined: Mon Jun 27, 2016 9:44 am

Rover 416GSi 1990 misfiring after storage

Post by guynosborne »

I'm sure that this topic must have been well aired previously, but maybe someone has some up-to-date information for me. I use E5 petrol, but when I garage my car (1990 416 Gsi with Honda engine, only 261000 miles!) and keep it there for say over two months, on start up it will run soundly for 5 minutes then the engine will start to splutter and misfire and if I dare to switch it off will usually not restart for up to 20 minutes. The misfiring is accompanied by white exhaust vapour (steam?) and even water dribbling out of the exhaust. I usually persevere long enough until the engine runs smoothly again. On continued use there is no problem until I garage it again, and if that is long enough the same problem starts all over again.
I have long thought that water contamination was the problem, but was puzzled as to where it was coming from as the car is normally garaged. However, I now realise that the water is probably coming from the dissociation of the 5% ethanol/water blend additive that is added to E5 to help global warming, and until this clears misfiring will occur.
So how to deal with this problem? Maybe I should take it out every week and give it a run around to clear the fuel. Of course, also I may have misdiagnosed the problem, but if not look forward to any comments that you may have as there must be members who also store their Rovers for longish periods.
The engine oil is changed regularly and is as clear as a bell.
Regards Guy Osborne
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g259fsg
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Joined: Sun May 20, 2007 6:38 pm
Location: Dunfermline

Re: Rover 412GSi 1990 misfiring after storage

Post by g259fsg »

White exhaust fumes sometimes indicates a head gasket failure when a small amount of coolant leaks across into a cylinder. It may not contaminate the engine oil, it depends where it's leaking and how much. Is the coolant level full or does it drop at all? Leaving the car standing for a while could allow coolant to seep into one of the cylinders. I did have a problem like this two or three years ago, the subject of a lengthy thread on the forum https://rover200.org.uk/forums/topic/15296

Although I'm not certain, I wouldn't think the ethanol in E5 petrol absorbing water from the air would be enough to cause a problem like that. The petrol tank is sealed and presumably with a limited breather system, so I wouldn't think there'd be enough moisture in the trapped air in the tank to cause a problem. If you suspect this, does the problem vary depending on how full the tank is? If it still has the problem with the tank nearly full, it would suggest the fuel isn't the problem. Certainly on the 1.4 engines, the fuel is constantly recirculated to the tank so the engine should be getting fresh petrol at the injectors. I also use E5 petrol in my Rootes cars and they stand for quite long periods in the winter, but don't show these problems when started up.
1990 Rover 214 GSi (VIN 222977)
1964 Humber Super Snipe Series V
1965 Humber Sceptre Mk.1
1966 Hillman Minx Series VI
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g259fsg
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Joined: Sun May 20, 2007 6:38 pm
Location: Dunfermline

Re: Rover 416GSi 1990 misfiring after storage

Post by g259fsg »

One other thought. Are all the ignition components reasonably new, particularly the leads and the rotor arm? They could get a bit damp if left unused for periods. I doubt if this is the problem as you would have more trouble getting it started from cold. None of this would explain the excess water vapour in the exhaust.

One other possible cause is the coolant temperature sensor being faulty or intermittent so the ECU isn't setting the right air/fuel mixture.
ROVER Cabby
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Re: Rover 416GSi 1990 misfiring after storage

Post by ROVER Cabby »

As mentioned above, check the plugs, leads, cap.

I'd also check for a vacuum leak by spraying brake cleaner around vac hoses and the intske manifold.
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