What is the proper procedure to check compression? I checked compression twice. Car was cold, I took out spark plugs, screwed in compression tester and cranked the engine few times. At first crank compression is low and it gets into normal range at second crank. Also If I crank the engine few times before I check compression, first crank reading is way higher. Am I doing it right?

What is the secondary ignition?

Thanks

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1999 ML430 Silver 135k ml
Smoked LED taillights, Alpine in-dash DVD player, 12" sub, Pioneer components, 2 amps, 4200k HIDs, ML55 headlights, 20" rims, mirror LED blinkers

SOLD. 1996 E320 145k ml. Burgundy

SOLD but miss it everyday 1992 500sel Black
Chime buzzer mod,Alpine CD/MP3 player with stock amp,Euro headlights,S600 grill,20" rims, BEST CAR EVER!

SOLD. 1990 300E White
187k ml,smoked tails,Euro headlights,17rims,Intake,12" sub in first aid kit,alarm/autostart,buzzer mod