Loss of compression?


#1

I have a 97 318is, 250,000 miles, runs great, except for onetime I was driving up a mountain in PA, and the top speed was 30 mph, pedal to the floor. Do I need a ring job?


#2

You need a compression test to either confirm or deny that. And unfortunately I can’t do that over the inter-webs.


#3

What makes you jump right to that thought? how does it run any other time? i know you said good but does it have power?


#4

@Arch1 What gear were you in driivng to that mountaintop. Any better results in another gear?


#5

One possibility might be an exhaust restriction. A plugged up catalytic converter will cause the problem you experienced. A good mechanic can check for this problem with a vacuum gauge.


#6

In addition to pondering the issues raised by the other forum members, here is another one for the OP to think about:

If you happened to glance at the tachometer during that 30 mph hill climb…
At how many RPMs was the engine turning?
Is that the normal RPM range for your engine, in whatever gear you were driving in?