ice445
Well-Known Member
- Joined
- Apr 13, 2020
- Threads
- 34
- Messages
- 6,203
- Reaction score
- 7,386
- Location
- Salt Lake City, UT
- First Name
- Ryan
- Vehicle(s)
- 2020 Mustang GT 6MT
What's more important than anything else right now is that the Ford engineers didn't agree with the initial dealership assessment, which is why they don't want to throw an engine at it right away. If it actually has low compression in a cylinder (and we're defining "low" as more than 10% under the average of the other 7), then it's not going to go away any time soon. But as I said, it's easy to get a "low" result. For one thing, most of the tools aren't always that accurate to begin with. You also have to crank for the same amount of time for each cylinder, and it's easy to be off on that and get a lower number. The test is supposed to measure consistency, but at the same time, on any Ford made in the last 20 years you can do what's called a "power balance" test, where you put the car into a monitor mode and it cranks itself and measures the resistance each cylinder provides based on crank trigger pulse width. It provides you with a neat little graph and any low spots indicate a cylinder that's low on compression compared to the others. If they also did that and saw a problem, then I'd be more concerned. Until then, I'd assume it's a fluke.Thanks for another great bit of info. I’ll be happy if it doesn’t need an engine replacement. A list of little problems that dealerships mistake for engine failure would be pretty handy, could save someone the cost of a Golf in an unnecessary repair.
They’re putting the new alternator in today, then running more diagnostics. I’ll update the thread when I get more info. If by “low compression” the nice lady meant “low power” as measured on a scan tool then maybe it’s electrical. By low compression I was thinking of the old school tool that screws in to the spark plug hole and measures compression - which would not be electrical.
Also, I've noticed at many dealerships that communication between the tech, the service writer, and the customer is the most obscenely deficient game of telephone you'll ever play in your life.
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