Cylinder compression test via obd?
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Cylinder compression test via obd?
I sold an old pair of tow mirrors the other day, and I was talking powerstrokes with the fellow who picked them up. I told him I was thinking about having a compression test done on my truck in the near future, cuz at it's mileage I wanna see just how worn out it is before I have a transmission go bad or something else that costs a good bit to fix.
At that point he told me a good shop could do a compression and leakdown test just with the right scan tool, via the obd, and not need to pull the valve covers, etc. And he was saying this in relation to the 7.3, not just like generic engines.
Is this true with the 7.3s? I had always been under the impression from the reading I'd done you had to do a manual check with the correct gauges and going into the glow plugs ports, etc.
My truck is currently running fine, and the blowby looks normal, I'm just thinking about doing the compression test sometime just so I know.
At that point he told me a good shop could do a compression and leakdown test just with the right scan tool, via the obd, and not need to pull the valve covers, etc. And he was saying this in relation to the 7.3, not just like generic engines.
Is this true with the 7.3s? I had always been under the impression from the reading I'd done you had to do a manual check with the correct gauges and going into the glow plugs ports, etc.
My truck is currently running fine, and the blowby looks normal, I'm just thinking about doing the compression test sometime just so I know.
More Turbo
Joined: May 2016
Posts: 717
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A Compression and Leak-Down Test are Manual Tests on all Internal Combustion Engines. These are the most accurate; real-time pressure measured in the Cylinder at specific times.
Other Options Available for Diagnosis is a Cylinder Contribution Test. Which, could indicate the Need for either of the above.
A Cranking Compression Test is done with an Oscilloscope. This Graphs the Rotational Resistance of the Cylinders while Cranking the Engine. This test is used to diagnose which cylinder, if any, would require a Mechanical repair.
Other Options Available for Diagnosis is a Cylinder Contribution Test. Which, could indicate the Need for either of the above.
A Cranking Compression Test is done with an Oscilloscope. This Graphs the Rotational Resistance of the Cylinders while Cranking the Engine. This test is used to diagnose which cylinder, if any, would require a Mechanical repair.
Cargo Master
Joined: Mar 2002
Posts: 3,132
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From: W (BY GOD) V
What he was referring to is a cylinder balance test to determine if any further diagnostics is needed. Most professional scan tools now have this feature.
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