Change in perceived power around around mid rev range
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06-13-2008, 05:01 PM
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Change in perceived power around around mid rev range
Evening all
I have a 130,000 mile 850, equipped with the B5252 - 2.5L, 10v, unblown, with autobox. In addition to this I have a dying exhaust manifold. The flexible mesh joint leaks somewhat, enough to cause an emission failure at the MOT. It passed eventually by being bandaged with something, but that has since either burnt or flown off. (Top engine mount died causing the engine to rock and break the manifold, I think.)
My symptom appears to be a significant / noticable change in power when accelerating the car through the 3k rpm area. I cant tell if, before the power increases, it feels sluggish, or that this power is in addition to what I thought was normal before. But what I do feel is more pull coming on at about 3k rpm. Effect is more noticable with engine on the colder side.
To reproduce: from stand still, gentle throttle until 20mph then three-quarters throttle until 70mph. In (i think 2nd gear) around the 3k rpm the effect is preceived.
Maybe this is not the engine, but the gearbox? What possibilities could this be? Fuel pump? Ignition? Dead injectors?
Shame its not some variable valve timing kicking in or a turbo spooling up!
Hope to hear your ideas!
Rich
I have a 130,000 mile 850, equipped with the B5252 - 2.5L, 10v, unblown, with autobox. In addition to this I have a dying exhaust manifold. The flexible mesh joint leaks somewhat, enough to cause an emission failure at the MOT. It passed eventually by being bandaged with something, but that has since either burnt or flown off. (Top engine mount died causing the engine to rock and break the manifold, I think.)
My symptom appears to be a significant / noticable change in power when accelerating the car through the 3k rpm area. I cant tell if, before the power increases, it feels sluggish, or that this power is in addition to what I thought was normal before. But what I do feel is more pull coming on at about 3k rpm. Effect is more noticable with engine on the colder side.
To reproduce: from stand still, gentle throttle until 20mph then three-quarters throttle until 70mph. In (i think 2nd gear) around the 3k rpm the effect is preceived.
Maybe this is not the engine, but the gearbox? What possibilities could this be? Fuel pump? Ignition? Dead injectors?
Shame its not some variable valve timing kicking in or a turbo spooling up!
Hope to hear your ideas!
Rich
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