Real life Compression Test Results

Have not done Prius, but with all previous cars and motorcycles I cranked until the pressure stabilized.
On Aircraft used a leak down method with a pressurized air feed through an calibrated nozzle, IIRC .

 

Did you warm the engine thoroughly before the test? Very important!! Cold engine will give lower pressures than really true. But getting plugs out when engine is hot is a real pita.

From your second link, I read that

1. Standard compression pressure:
   1373 kPa (14.0 kgf/cm2, 199 psi) or more Minimum pressure:
   1079 kPa (11.0 kgf/cm2, 157 psi)
   Pressure difference between each cylinder: 98 kPa (1.0 kgf/cm2, 14.2 psi) or less
   
   So your later 144 pressures are low.
   Did you put a bit of oil in the cylinder and recheck the pressures as the PDF recommended? If pressure comes up to normal, worn rings are likely; if pressure stays low burned valves are likely. But please make sure gauge is calibrated so you are working with accurate data.

 

Thank you for starting this. Here is my data for my Generation 2 Prius.

1. 2006 Prius with 145,000 miles
2.
140,145,145,? - Dry with throttle wide open (failed to record cylinder 4, but recall it was comparable),
178,171,170,172 - wet with throttle wide open (with a teaspoon of oil squirted through each spark plug hole)
3. manually cranked the engine without techstream, vci or anything like that. (i did neglect to press the gas/accelerator pedal but I did see that the throttle opened fully. (I removed the air filter housing to better access the plugs, injectors, and pcv valve.)
4. slightly warm engine (about a half hour after driving.) fuel injectors disconnected
5. OEM compression test kit from Autozone
6. Car was burning nearly a quart of oil every 1,000 miles. OBD kept throwing a P0420 for an ineffective catalytic converter. I hoped to determine where oil was entering the cylinders. (Apparently past worn rings.)
7. When I first tried measuring the compression, I failed to notice that a plastic bag I'd placed over the throttle intake was nearly sealing it during cranking, preventing much air from entering the engine. Before I corrected this my compression measurements were 128, 125, 114, 115 without oil added to the cylinders. Again, these are for the 1.5L engine in the Gen 2 Prius.

I cannot find specs for what the gen 2 compression measurements should be. I'm not sure how comparable they'd be as I did a manual test without techstream or vci.

Do these wet and dry numbers suggest that the engine is worn but still has quite a bit of life in it? How many miles more do you think this engine will last before it will not perform reliably and pass emissions tests? Should I start planning now to replace the engine or sell the car to someone prepared to do this?

 

Just had my 2015 gen 3 Prius V5 in for its 75000 mile service had a time cover oil leak that was fixed under warranty I also replaced the plugs and had a compression and leakdown test done, by the dealer here are my numbers:
Cyl 1 124 psi 96% Cyl2 122psi 96% Cyl3 121psi 95% Cyl4 121psi 94% so Cyl 4 is the lowest of the bunch has anyone else have figures also? I bought this used CPO and have done all the recommended services fluid changes and use synthetic oil ...

 

IIRC, the leak down type of compression test would have different results depending on the size of of the orifice in the high-pressure air supply line. Thus, that result may not be directly comparable to the old-fashioned pressure-gauge-in-sparkplug-socket type of compression measurement (which is the type I have the most experience with). @DTKim cited two standards for the compression results, but I could only access the earlier PDF of the repair manual procedure , not the newer official Toyota techinfo version he cited as it is behind a paywall. I have not done this test on our 2012 hatchback so I hope some others will chime in with their results for the 2010-2015 Prius models.

 

Glad to see “real life” data that’s not like the typical fake results posted on here

 

I tested my 2010 Prius using Techstream/Hybrid Drive/Active Test/Compression Test. Engine was warmed to 185F coolant temp with windshield wiper cowl removed, so plugs could be removed quickly. Car has 121k miles, has always been on synthetic oil, it consumes no oil to speak of. Results: 132, 135, 128, 130 psi. Leakdown numbers pending.

 

Using OTC 5609 leakdown tester, engine warm... 100/99+, 100/99+, 100/99, 100/99+. On all four, a tiny hiss is audible at the oil filler cap.

Conclusion: "199 psi" specification is crazy wrong, and 118 psi spec is wrong too. Inspection of all four cylinders shows everything clean and dry.

 

The OTC tool isn't a compression tester, it's a leak down tester (google is your friend -- I don't have time to go find a description right now). What it is showing is that my engine is basically perfect (it's coming out of the car shortly for other reasons, but that's a whole 'nother story (transmission input damper problem)).

 

I set things up so I could read the gauge while cranking, and I cranked until the gauge topped out... plus a couple extra to be certain. I didn't count the compression strokes, something like 8 - 10. Six seconds or so of cranking.

 

I just purchased a 2006 Prius with 196K miles. 12V and hybrid batteries are bad. Tested the compression with a leak-down tester, and it is showing about 90's warm with full crank (until it stops) and about 140 after putting oil in the cylinder. I'm thinking this vehicle is toast. Body is good, interior not bad. I could sell it as is for $1k and recoup my money. What do ya think?