Hey guys I just bought a RCT-V5.2 rotary compressor from rotary CompressionTester.com
and it won’t give me pulse when I crank engine on front rotor but it does work on back rotor which I got Psi: 98 91 84 I don’t know what could be the problem I connect it right I have unplugged Main fuse EGi just won’t work on front rotor. If anybody know what went wrong or what am I doing wrong.I have a 1988 Mazda fc convertible rx7 13b non turbo hasn't being moved for 3 years

 

Can you hear any pulses in the front rotor when you listen?

Some readers will show "zero" if compression is less that 33 psi.

 

I don't know what the threshold is for the rctv but I want to say anything below 22 i think is an effective 0. Of course it needs SOME compression to activate. Odds are you have 0 in the front if it isn't registering. Crank it with the spark plug out and listen for pulses

 

Sorry to say it but if you're getting normal looking readings on one rotor but it's not giving you any reading not the other your problem is with the motor not the tester. Obviously this assumes you hooked it up correctly to test both rotors. As FDAUTO and Redbul implied, there's a lower compression threshold where the RCT V5.2 won't read anything/display zeros.

Another thing to consider is cranking RPM - if your battery is really weak, and you did the "good" rotor 1st, and then tried to test the "bad" rotor, it's possible that you sapped out the battery enough that the starter can't give you enough cranking RPMs to get a compression reading on that 2nd rotor. Maybe try again with a charger/jump starter hooked up.

 

I will try with jumper this afternoon

 

I can hear it the compressor won’t read it when it says start cranking

 

I cranked it with both spark plugs out

 

Happens all the time.

 

Both plugs (L & T) on the same rotor out? That would definitively get you a zero/invalid reading on that rotor. The RCT V5.2 instructions say to only remove the trailing (top) plug of the rotor under test.

 

I meant Both T were out