I was stupid and unplugged the o2 sensor (the triangle one in the spark plug area) thinking it was the crank sensor when I was performing the comp test

Evo 8, 2005, 71k miles.

Car was hot, stock block, GSC valvetrain with Kelford 272s. Borrowed a tester from Oreillys Part store, got 115 across the board with WOT on the gas and clutch, 5-7 crank overs.

Seems strange that the car is running so well with 'low' comp, or that the fuel being shot in would skew it. Car made 380whp/320 trq (stock turbo, 20 psi) 5 years ago at English, and then the same number a few months ago, at English again, same month roughly.

Would ignition and fuel cause a different compression number since the crank sensor was still plugged in?

Im thinking to just send it, or use another gauge + unplugging right sensor lol

 

The main reason for unplugging the crank sensor is to keep gasoline from spewing from the cylinders.

Edit: Not the main reason, the reason.

 

The best way is to pull the fuse for the ECU.

Yes fuel in the cylinders will make the numbers a bit higher.
It's also a fire hazard.

115 PSI is a bit low?


Do it again ?

 

Try another gauge, also make sure the Schrader valve in the line is working properly. I had one that was a little difficult to move, and it made the gauge read low because it wasn't opening all the way.. 115 is on the low side. Should be at least 140..

 

I just did my compression test and watched my new gauge needle bounce 20 psi with each crank. You get what you paid for. Now I'm searching for my old one. Would changing the valve fix the problem?
I watched the compression drop 20 psi with 2 cycles and thought to myself: how did that happen? $30 down the drain.

 

Might do it again this weekend. Having all 4 at the same is just odd to me and everyone I've talked to that has driven and or worked on my car lol

 

Lots of broken engines out there?


Compression tests are pretty much waste of time.

Looking at the sparkplugs usually tells you everything you need to know.

Photos?

 

Unsure on the tons of broken engine part lol

They were like a medium shade of grey

I'll check again this weekend

 

Waiting on photos?
Real ones.
Not like the ones the last clown on here got off google.

 

It's not this weekend yet 😒

 

 

I looked at my new compression gauge and the Schrader valve is inside the screw part. I can't get to it to switch out.

 

Fwiw this is what I used

I returned it already

I'll use my friends on Sunday and check the plugs again

 

Dono why this pic didn't upload

 

I took this pic after I did my plugs, did these like 3 weeks ago or so right before my dyno tune

Sorry for such a huge pic

The car made 497whp 380 trq at 31 psi on a dyno jet 92 octane with a FP red SS
We backed it off cause the CEL was flashing, running about 24 pounds right now probably around 460~