low compression cause

[Spoolin18]

Would a low discharged battery cause a cyl to show low compression #'s, it was the 1st cyl and he had to recharge the battery several times. Plus, I had trouble out of the battery. Haven't done any test since, the car shows no symptoms of low comp.

 

[kottyking]

Your car battery has absolutely NOTHING to do with cylinder compression.

 

[EclipticalGS]

well if the battery can barely crank the motor over, how is he going to get a good reading?? Your supposed to see 5 bumps of pressure on the gauge. Thats you compression.

 

[Derock2gspyder]

ya you need power to turn the car over so you need a good battery otherwise it will show really low! but you should be showing low across all four cylinders so just throw a good battery in and see what it does then!

 

[kottyking]

well if the battery can barely crank the motor over, how is he going to get a good reading?? Your supposed to see 5 bumps of pressure on the gauge. Thats you compression.

Yea but if it cranks the car over, it cranks the car over. It doesn't crank it half ass because the battery is low. Once you turn the key, its all on the ignition system after that. Obviously if the battery is DEAD, its not gonna start. But if it's a "lower voltage battery" the reading will still be good if you do it correctly.

 

[YZFR1]

A low voltage battery is not going to have as good of a cranking speed. So it does affect the compression, however, like Derock said it should be bad across the board. If only one of the cylinders reads bad, than obviously something is wrong.

 

[EclipticalGS]

Im saying, what if the battery cranked fine for the first 3 cylinders, and then loss its juice during the 4th cylinder. It would make sense.

 

[1995gsx20g]

Im saying, what if the battery cranked fine for the first 3 cylinders, and then loss its juice during the 4th cylinder. It would make sense.

yes that makes sense but whenever i do a comp test i pull all of the plugs out first so the starter has no issues cranking it over many times only having to create compression on one cyl

 

[EclipticalGS]

Same here, but the big words here GET A NEW BATTERY, TRY AGAIN

 

[Spoolin18]

the battery was low on the first test.