Engine diagnostics using engine vacuum
 

Interesting site about using engine vacuum to find out what's wrong with your engine.

http://www.dennysgettogether.com/den...roject_018.htm

Re: Engine diagnostics using engine vacuum
 

Good stuff.

Re: Engine diagnostics using engine vacuum
 

Nice! vacuum gauge reading and ignition analyzers (o'scopes) are kind of a lost art.

Re: Engine diagnostics using engine vacuum
 

Mike,

A vacuum gauge and a tach were the first tools used by tuners of the early ECMs. :saluting:

Re: Engine diagnostics using engine vacuum
 

I especially liked the flash animation as some descriptions in books (remember those) were a little difficult to imagine. Most interesting were the worn ring ones that could be a quick way to assess the health of an engine without taking the trouble to do a compression test.

Re: Engine diagnostics using engine vacuum
 

Does anybody need a dwell meter and timing light? Mine are unused these days.

Re: Engine diagnostics using engine vacuum
 

That's funny. I just gave my nephew a Sears adjustable timing light which I have not used in 8 years. He was rebuilding an old Yamaha 70's 650 cafe racer and was timing the motor. That and setting points is a lost art.

Re: Engine diagnostics using engine vacuum
 

Yeah, that's why we keep Ami's ol' 69 C3 vert around - soze I can remember what a PIA tuning is/was before modern ECMs (and the like). I have a couple drawers in my hi-boy tool chest, dedicated to that car.

It's amazing how much art about engine analysis has been lost since the computers took over tho. But, it is good to have known it once, cuz every now and then (especially with OBD-I) a problem occurs that the ECM/sensors won't display - e.g., the leaking exhaust valve my Z developed (as result of a bad injector(?).

Re: Engine diagnostics using engine vacuum
 

I use dwell meters and timing lights all the time. All my older Corvetts require tuning all the time, specially the old Rochester fuel injections. The vacumm guage also comes in handy. My c2s and my c3s, the head lights, the a/c, the windshield wipers and distributors are all controlled by vacuum. Something always seem to be leaking.
Nelson007

Re: Engine diagnostics using engine vacuum
 

How much vacuum should you read on a stock 1991 at idle?