Visiting on behalf of a friend with a problem with his 1999 BMW 318iS. He was travelling to the Touring Cars at Knockhill yesterday and experienced an odd loss of power with the car.
When he first described it to me he said it would accelerate fine in any gear up to 4k rpm and then the power would just die. He also mentioned a slightly raspy sound which he reckons is a small hole in his exhaust. When he got back home last night he phoned to tell me that it hadn't gone away and on the way up a hill on the motorway, he got to the bottom at 70mph and the top at 15mph. If he depresses the accelerator more than a third of the way down, it just chugs but it's fine apart from that - just sounds a little raspy.
Any ideas?? It has been suggested that it might be fuel pump related or something to do with seals in the engine. Neither of which sounded convincing to me. Its booked in on Friday to the dealer, but he would like a wee bit of good news if there is any!
sounds like it could be a clogged catalytic converter.... Thats where I would start if it were my car.... the reason that it may sound raspy is if the cat is clogged and there is a hole in the exhaust... there is now a lot more back pressure and as such a lot more exhaust being pushed through that leak...
There is no popping at all from the exhaust and the power is only available if he gently accelerates (about 1/3 depressed) under 4k rpm. There is nothing above 4k just noise and nothing more in the way of power.
Basically there is a lot that it could be. He might not be getting enough fuel or enough air, or there is a large vaccum leak, or as was mentioned either is cat or other part of exhaust is clogged. I don't see how to diagnos it unless either you or him really know their way around a car. If that is not the case, he is most likely going to have to take it in either to a dealership or a car repair shop that is knowledgeable with BMWs. Theres just too much that it could be for me to be any more help without being able to poke around in the car.
I am fairly happy poking around under the bonnet and would probably be able to rule out a few of the suggestions myself. Problem is that i live 65 miles from the car and don't have the time to see it this week. He has booked it into his local dealership tomorrow (Friday 13th ).
Thanks for all the suggestions and i'll post up the cause of the problem when its known.
would you know if he has recently taken anything apart like the starter? When i had to take my starter out, we had to disconnect a sensor and when we put it back in, the car would not rev past 4k rpm's and it would just die. We found out that the sensor hadn't been put in all the way
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