What would you think of a tool that cost $20-30 and could diagnose many engine problems including, low compression, bad rings, burned and sticking valve(s), bad valve guides, bad cat or exhaust restriction, restricted intake and a host of other common issues. A tool small enough to take with you when looking at a used car and quick enough to use to get a good idea on the general health of the engine?
I made a post bout this tool in clinebargers thread and decided it deserved a thread of its own. When I first started which was decades before the ECM or OBD we had points condenser, rotor and wires and the primary diagnostic tools were a tach/dwell, timing light, multi meter, compression tester and vacuum gauge, if you worked in a shop they may have had a scope.
The one tool that has been for the most part ignored today is the vacuum gauge, this is one tool that I would really miss if I didn't have one. The first time I saw one of these was in a early 60's car and it was labeled economy meter, the trick was for the driver to keep it as close as possible in the green area.
Even in trade school in the early 70's they mostly brushed past the usefulness of this tool.
The gauge is largely associated with carburetor engines but it works equally as well on FI as long as you can find full manifold vacuum somewhere, you can T in in you have to. It does not work on diesel engines as they produce very little vacuum but it can be used to diagnose the vacuum pump commonly found on them. Large cam engines may have lower vacuum levels but needle reactions will be the same.
I did a VW with flashing CEL and no power, suspected bad cat right of the bat, sure enough the vacuum gauge showed it right away, further testing confirmed high back pressure, off with the cat and surprise nothing in it. It had broken up and filled the muffler inlet. The vacuum gauge diagnosed this in seconds with no parts removal or wrenching.
This is a good site to see how one works and the amazon link is a OTC gauge for under $30
http://www.secondchancegarage.com/public/186.cfm
OTC gauge
I made a post bout this tool in clinebargers thread and decided it deserved a thread of its own. When I first started which was decades before the ECM or OBD we had points condenser, rotor and wires and the primary diagnostic tools were a tach/dwell, timing light, multi meter, compression tester and vacuum gauge, if you worked in a shop they may have had a scope.
The one tool that has been for the most part ignored today is the vacuum gauge, this is one tool that I would really miss if I didn't have one. The first time I saw one of these was in a early 60's car and it was labeled economy meter, the trick was for the driver to keep it as close as possible in the green area.
Even in trade school in the early 70's they mostly brushed past the usefulness of this tool.
The gauge is largely associated with carburetor engines but it works equally as well on FI as long as you can find full manifold vacuum somewhere, you can T in in you have to. It does not work on diesel engines as they produce very little vacuum but it can be used to diagnose the vacuum pump commonly found on them. Large cam engines may have lower vacuum levels but needle reactions will be the same.
I did a VW with flashing CEL and no power, suspected bad cat right of the bat, sure enough the vacuum gauge showed it right away, further testing confirmed high back pressure, off with the cat and surprise nothing in it. It had broken up and filled the muffler inlet. The vacuum gauge diagnosed this in seconds with no parts removal or wrenching.
This is a good site to see how one works and the amazon link is a OTC gauge for under $30
http://www.secondchancegarage.com/public/186.cfm
OTC gauge