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Chevy 1.5L Turbo Engine Question
cbxjeff
Member Posts: 17,599 ✭✭✭✭
My son has a 2016 Malibu that has a misfire. He ran a compression check and one cylinder is about 110 psi. The other 3 measure about 220 psi. How can a 10:1 engine have 220 psi at cranking speed? Maybe his gauge is faulty. OK guys, start telling me that he should have bought a Ford!
Thanks anyway,
It's too late for me, save yourself.
Comments
OK
he should have bought a Ford!
Theoretically possible. As temperature increases, so does pressure, which increases temperature, which increases pressure.
So, if the volume is 1/10 and the temperature increase is 1.5 (absolute), you could get to 220 psi.
Somewhere in that empty space that was my brain I remember PV=nRT, which describes the relationship.
Folks with a better memory than mine may be able to flush out the details.
Brad Steele
The calculation and thought process is correct Don. You could see a temp rise of 1.5 if he is doing a test on a hot engine and it's a cool day, maybe even more. But for a 10:1 engine you should be at about 150 psi. I would do the test with a cool engine and if you're still getting these high numbers I would look at trying a different gauge.
And fiery auto crashes
Some will die in hot pursuit
While sifting through my ashes
Some will fall in love with life
And drink it from a fountain
That is pouring like an avalanche
Coming down the mountain
The 110 cylinder has a bad piston noteable for those engines. Most problems occur from the engine not warming up and the gas getting mixed by blow by into the crankcase oil.
Weed eater?
Let's see, a 1.5L car engine?? Must be wound pretty tight just to move a car. Highly fueled, turbo'd engine has low compression in ONE cylinder?? Piston has a hole burned in it. Possibly due to clogged injector not producing a good spray pattern.
Unless the rings are bad, doesn't really make any diff how fast the piston is moving while making compression.
BTW, my UTV has a 1.0L engine and the whole rig weighs only 800#. Why would anyone think it's a good idea to put a lawnmower engine in a car?
It's not really a 'car' if you have to snug up the laces after getting in.
Well the head and pan is off. Pistons are out and #1 has a 1/4" hole through it at the middle of the group of ring glands. That may be the reason for low compression. I'm surprised it had any at all! I was surprised that the pistons were $100.00 ea but when I got them they came assembled with rings and rods. Now I'm thinking that the compression numbers were the result of a bad gauge. Take about 100 psi of the original numbers and I can believe it.