Engine cutting out when accelerating above 3000rpm
Discussion
Hi,
I have an S reg Rover 400 2 litre sli - only had it a couple of years, so don't know much of it's history.
It's been a great car, but last year I think something went wrong with the alternator - basically - the battery runs down every time I leave the car for a few hours with ignition off. I checked as much of the electrics as I can, and could find no where shorting out - and I hear that this engine can have rectifier issues - so had been guessing it could be this. Anyway I fixed this prob by simply removing one of the battery connectors every time I stop the car for a period. Bit of a pain, but been waiting to see if car will make it to next MOT - before getting it fixed, as am broke, and only use the car for long journey to family/friends - not for commuting, so rarely used.
Anyway - gave you the back story in case you think this could have any baring on the current issue.
Drove 5 hours to Devon on Friday from London. Car was fine.
Left parked and started to drive home on Sunday. Was struggling to accelerate fast, but seemed fine - just figured engine was cold, then about 30 minutes into journey as was picking up speed to hit motorway the engine seemed to lose all power. Stamping on clutch and taking foot off accelerator the engine seemed to go back to normal revs - so again I tried to pick up speed as road was clear. Again same thing happened. On hard shoulder - looked at rev counter and noticed that basically this happened when hit 3000rpm - so as a service station was 9 miles ahead I limped the car on there keeping it under 3000rpm (about 60mph - so was safe to be on m-way)
Got there and called AA - but they wouldn't come out until the car would not start/run - so drove at 60mph all the way home (amazing how good petrol consumption is at that speed)
Anyway, last night had to give my brother a lift and after warming up engine for a minute found that now wasn't letting me get above 1500rpm. Was late and he was going to miss last bus so limped it on again - but after a few minutes could get to 2000rpm with out cutting out, then be time was home again was going up to 3000 again.
Anyway - going to give it more of a look over tomorrow. So far with my limited knowledge i've loooked into the followin: does not seem to be oil in water, does not have water in oil - no excessive smoking - bit of a rattle to engine, but nothing major.
Any ideas? Change spark plugs? Air filter (was wondering if it wasn't getting enough air?)
Cheers, and let me know if I can provide any more info - and thanks for reading this far! I owe you one!
Crow
I have an S reg Rover 400 2 litre sli - only had it a couple of years, so don't know much of it's history.
It's been a great car, but last year I think something went wrong with the alternator - basically - the battery runs down every time I leave the car for a few hours with ignition off. I checked as much of the electrics as I can, and could find no where shorting out - and I hear that this engine can have rectifier issues - so had been guessing it could be this. Anyway I fixed this prob by simply removing one of the battery connectors every time I stop the car for a period. Bit of a pain, but been waiting to see if car will make it to next MOT - before getting it fixed, as am broke, and only use the car for long journey to family/friends - not for commuting, so rarely used.
Anyway - gave you the back story in case you think this could have any baring on the current issue.
Drove 5 hours to Devon on Friday from London. Car was fine.
Left parked and started to drive home on Sunday. Was struggling to accelerate fast, but seemed fine - just figured engine was cold, then about 30 minutes into journey as was picking up speed to hit motorway the engine seemed to lose all power. Stamping on clutch and taking foot off accelerator the engine seemed to go back to normal revs - so again I tried to pick up speed as road was clear. Again same thing happened. On hard shoulder - looked at rev counter and noticed that basically this happened when hit 3000rpm - so as a service station was 9 miles ahead I limped the car on there keeping it under 3000rpm (about 60mph - so was safe to be on m-way)
Got there and called AA - but they wouldn't come out until the car would not start/run - so drove at 60mph all the way home (amazing how good petrol consumption is at that speed)
Anyway, last night had to give my brother a lift and after warming up engine for a minute found that now wasn't letting me get above 1500rpm. Was late and he was going to miss last bus so limped it on again - but after a few minutes could get to 2000rpm with out cutting out, then be time was home again was going up to 3000 again.
Anyway - going to give it more of a look over tomorrow. So far with my limited knowledge i've loooked into the followin: does not seem to be oil in water, does not have water in oil - no excessive smoking - bit of a rattle to engine, but nothing major.
Any ideas? Change spark plugs? Air filter (was wondering if it wasn't getting enough air?)
Cheers, and let me know if I can provide any more info - and thanks for reading this far! I owe you one!
Crow
Given the known alternator issues it does sound a bit like the electrical system isn't getting enough voltage or current to power the ignition system properly. Get a digital multimeter and check the alternator output and battery voltages are in the right range. I suspect the parasitic drain is because a diode inside the alternator is shorted out. What this would do is still allow the alternator to produce about the correct voltage but not very much current so it might pass a basic voltage test but not a high load test. You can check to an extent by removing the battery connection wire to the alternator and seeing if the parasitic drain ceases. I think a new alternator would really be the best, or in fact only, solution though. The battery might also be pretty dead by now if this has been going on for a while so at higher rpm neither the battery nor the alternator can properly supply enough output to produce a decent spark.
Another test is to see what happens if you turn on a large electrical load while you're driving such as headlights plus screen heater, blower etc. If the misfire starts immediately you've got your answer.
My other thought would be a blocked fuel filter stopping the engine producing more than a certain amount of power but you might as well fix what you already know to be faulty first.
Yet another of my store of ancient vehicle related tales which may have some small bearing. Back in the 70s I was off to France on holiday with a mate, both on identical Honda 550 bikes which in the event turned out to be a godsend. Hardly had we set off to get the ferry at Portsmouth when my bike started misfiring on the motorway and I had to drive slower and slower until finally it all ground to a halt. I figured it out pretty much immediately. The battery was flat because the rectifier pack had failed. We swapped batteries and while his bike charged mine back up I drove on just the output from his battery which with the headlight off, which I normally always had on even in daytime, put out just enough juice to power the ignition for a while. That got us half way, more misfiring started and we then had to swap over batteries again.
We finally got to Portsmouth and still had just enough time to find a bike breakers in the phone book, shoot over there, amazingly thay actually had a second hand rectifier pack of the right type on the shelf, a couple of minutes frantic spannering to slap it in and we made the ferry with minutes to spare. I think that was the only thing on my Honda that ever went wrong in 30,000 miles but the gods were definitely with me that day. Another identical bike alongside to swap batteries with and a conveniently located shop that had the right part in stock. In other circumstances I'd have been completely stranded.
My dipstick mate then went and crashed his bike on the very first day in France, into the back of mine at a junction as it happens, bending his front forks so far back that the wheel was jammed between the exhaust headers and we both did the next 3000 miles on mine which luckily escaped unscathed from his tender ministrations. That's a whole 'nother story though but it was definitely an eventful trip.
Another test is to see what happens if you turn on a large electrical load while you're driving such as headlights plus screen heater, blower etc. If the misfire starts immediately you've got your answer.
My other thought would be a blocked fuel filter stopping the engine producing more than a certain amount of power but you might as well fix what you already know to be faulty first.
Yet another of my store of ancient vehicle related tales which may have some small bearing. Back in the 70s I was off to France on holiday with a mate, both on identical Honda 550 bikes which in the event turned out to be a godsend. Hardly had we set off to get the ferry at Portsmouth when my bike started misfiring on the motorway and I had to drive slower and slower until finally it all ground to a halt. I figured it out pretty much immediately. The battery was flat because the rectifier pack had failed. We swapped batteries and while his bike charged mine back up I drove on just the output from his battery which with the headlight off, which I normally always had on even in daytime, put out just enough juice to power the ignition for a while. That got us half way, more misfiring started and we then had to swap over batteries again.
We finally got to Portsmouth and still had just enough time to find a bike breakers in the phone book, shoot over there, amazingly thay actually had a second hand rectifier pack of the right type on the shelf, a couple of minutes frantic spannering to slap it in and we made the ferry with minutes to spare. I think that was the only thing on my Honda that ever went wrong in 30,000 miles but the gods were definitely with me that day. Another identical bike alongside to swap batteries with and a conveniently located shop that had the right part in stock. In other circumstances I'd have been completely stranded.
My dipstick mate then went and crashed his bike on the very first day in France, into the back of mine at a junction as it happens, bending his front forks so far back that the wheel was jammed between the exhaust headers and we both did the next 3000 miles on mine which luckily escaped unscathed from his tender ministrations. That's a whole 'nother story though but it was definitely an eventful trip.
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