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2G Compression test

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Ces4rDSM

Proven Member
119
6
Feb 2, 2019
watsonville, California
I've been trying to get my compression numbers per cylinder and it looks like all cylinders read 60 psi. Please help I'm not sure what I'm doing wrong. I unplugged one spark plug at a time, spark plug wires are off and power is disconnected. I opened the throttle as much as I could with a screwdriver or yet still same results. Can it be the compression tester itself that I borrowed from Autozone ?
 
60 psi is absolutely wack. Are you sure you have the tester screwed all the way in tightly? And are you trying to crank the engine or just manually rotating it?

And by the way you can buy cheap testers on Ebay and Amazon if you want to and don't trust Autozone's.

Amazon

Ebay
 
Yea the tester hose connected by the psi gauge was like magnet or pull to remove type of thing so probably that. I only did one spark plug at time, thought it would read more accurate ‍♂️ Anyways thank you all for input I will try a different compression tester.
 
U should unhook the plug to your coil pack and pull ur fuel pump relay or fuse or w.e u don't want fuel pumping in there while your doing it and don't need to be accidentally shocked by a wire or something if u haven't done so already but sounds like the tester may be bad I know my tester has a big oring at the end of the threads so if it is missing compression may blow past the tool
 
I thought the tester would've been ok since it looked new I'm guessing it isn't working accuraty. I removed the spark plug connection although the fuel pump relay or fuse was still intact. I couldn't find it didn't think itd be a big issue unless I tried starting it too much .
 
You don't need to mess with the fuel at all, when you push the throttle wide open during start the injectors are off for flood clearing.
You want to have all the spark plugs removed
Install the pressure tester so that oring seals if it uses an oring, doesn't have to be really tight
Push the throttle pedal to the floor and turn the ignition to start
Let it spin for a little and the gauge should hold peak pressure for the cylinder being checked
 
Ohh ok I felt like there would be something integrated in the cars system that would make it ok to step on the throttle and not have worries about the fuel. I did as you're sayi but the most it would peak at was 75 psi and would go down to 60.
 
Yea I hope so too man, it shouldn't be correct if my motor runs ok except for sounds coming from it. Because 60 psi is inoperable conditions in the pistons if I'm correct. Anyways thank you all for your input, I wish the best with our killer dsms :hellyeah:
 
I'm guessing something weird is happening if all you get it 75-60 across the board with a "good/normal" running engine.
Did you let it spin over long enough, it takes a couple cycles per cylinder.
You'll normally see the gauge move upwards after each cylinder cycle before peaking out/stop gaining.
 
I tried letting it do its thing for a couple seconds before releasing the key in the ignition and trying it again. The psi measurement reads a peak high 70 or 80 then gradually goes to 60 psi or so. Hoping it's a tool malfunction :confused: damn autozone, I hope the torque wrench I borrowed isn't wrong too.
 
I tried letting it do its thing for a couple seconds before releasing the key in the ignition and trying it again. The psi measurement reads a peak high 70 or 80 then gradually goes to 60 psi or so. Hoping it's a tool malfunction :confused: damn autozone, I hope the torque wrench I borrowed isn't wrong too.
If the tester drop pressure it's go get another one
 
Dang I need to proofread. Lots of typos.
I am saying tester is bad. If pressure drops after test is complete that's wrong. Tester should hold until user releases it.
 
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