Bought a Factory Compression tester at a dealership closing. The tester will activate when connected to battery. Can't get any readings. I did a search on forum but with no results> Anyone know about repairs or what goes wrong with these. Looks like it has a sensor that changes the pressure to electrical pulse. Thnnks for any info.

 

best bet is to have someone who is familiar with electronics take a look at it, they sould know whats wrong right away

 

Just curious, do you have only one spark plug out on each rotor, or both? I know this is an obvious thing, but Ive made the mistake once. If you have both the L and T out, it will read zero. Make sure its only one plug per rotor that is out.
-a

 

out of subject but how much did u buy it for ?

 

$350.00 at dealer closing auction. Was packed in the orginal carton from mazda with instructions etc. Will keep checking. Perhaps the sensr is gummed up from sitting around.

 

with the mazda sensor you use the trailing plug hole. You leave the leading plugs along and keep the opposite trailing plug in also when testing. remove your EGI fuse and crank with the throttle fully opened.

If you have the instructions this should not be an issue but just thought I would make sure you were getting it done right.

Oh and lastly it could be that you dont have any compression on the motor you are testing but I hope that is not the case.

 

Ah, Looks like then we remove only one trailing plug at a time and run the test. The service manual show both plugs removed. Looks like we have a Saturday project to retest. Thanks for the info.