100% Failure on Leak down Test

EdsST

EdsST

Joined
Dec 26, 2004
Messages
103
Location
Panama City, FL
Bike
ST1300A
I just got back from my trip to Las Vegas and back. The 5000 mile trip went without a hitch. The first time I tried to start the bike the day after I returned and nothing happened. The starter was turning but the engine wasn't turning over (my first thought was the starter solinoid wasn't engaging the flywheel). Anyway couldn't get it started so I took in.

The dealer performed a leak down test and said that it had a 100% failure. They took off the valve covers and couldn't see any issues there. The next step as to remove the heads to look at the underside of the valves.

That's where we are as of now - I'm about to contact them and see what they've come up with.

Looking for you smart guys to help give me idea what wrong.

By the way am I glad I got the extended warranty now!!!!
 
Good luck, I'm clueless... as usual.
 
I don't see why they would jump to a leak down test if the bike isn't turning over. Don't let them pull the head. If they jumped to the leak down test from not turning over they probably don't know enough to have the valves closed to do the test. Sounds like you need to go somewhere else to me. Hope I understood your post correctly.

Starter or starter drive problem maybe.

The only reason I could think they would go there (lead down test) and get those results would be catastrophic engine failure which I doubt.
 
Skunkape said:
If they jumped to the leak down test from not turning over they probably don't know enough to have the valves closed to do the test.
Click to expand...

My sentiments exactly. Leakdown would be pretty far down on my list of things to do if the engine wouldn't start.

--Mark
 
Starter turning engine not turning. What would a leak test have to do with anything? :nuts1:

uhmm Id talk to the guy doing the work and find out their thought process.
Hopefully "epic" is not used in this thread.

Pulling the heads doesn't sound like something you want them to do warranty or not.
 
I'm confused. You said "The starter was turning but the engine wasn't turning over (my first thought was the starter solinoid wasn't engaging the flywheel)." So. The starter was turning, as in the electric starter motor itself was spinning. But the engine was not "turning over"? Do you mean that the crank was spinning and the pistons were (supposedly) going up and down, but the engine wasn't firing? If that's what you men, then it makes sense to try the leakdown. I mean, if they did find spark and fuel, compression is the next biggie so maybe they did a quick compression test and came up with blank.

But if you mean that the starter motor spun but did not cause the crank to spin, then yeah - compression would be an odd thing to check. It'd be time to pull the starter and see what's up in there.

The only reason I'm asking these obvious questions is because I've run into different personal opinions as to the meaning of the phrase, "turning over".
 
Not knowing what troubleshooting led them to doing this test it's hard to comment, but I will anyway.

***** are those idiots doing :confused:

Do you realize how rare an engine failure is on the ST or any modern engine?
 
I would think the shop would do a compression test before trying a leak down test. Of course both tests are impossible if the engine's crankshaft can't be rotated. There's no way to measure compression if the engine's crank isn't turning and the pistons aren't pumping air.

There's no single crank position where all the valves on all cylinders are closed at the same time. The valves must be completely closed on the cylinder you are testing for leakage. This means that the crank has to be moved to TDC for each of the four cylinders individually in order to test them.

Sounds like a communications issue with some terms mixed up or that shop has no idea what they are doing.
 
I'm not a smart guy, nor do I play one on tv... but I'm curious about your description of symptoms and the dealer testing and results.

You said it appeared the starter was turning but the engine wasn't... not engaging the flywheel. The dealer then performed a leak-down test and proclaimed a 100% failure.

What did the dealer mean by "100%" failure? A leak-down test uses air pumped in through the spark plug hole, to measure the condition of the cylinder by the percentage of air that escapes... typically a good engine will be in the 5-10% range; 10-20% will still run ok; while anything above 30% indicates a problem likely requiring a rebuild or renew. I suspect you'd experience hard-starting and rough operation somewhere along the way.

So, what does a 100% failure mean???

If the dealer means 100% air loss during the test, I'd be real sure they were doing the test properly... like moving the pistons to Top Dead Center (both intake and exhaust valves closed!)!!! Barring instantaneous CATASTROPHIC damage, I'd expect variations between the cylinders, not total failure from one day to the next (did they test more than one cylinder?). If the pistons weren't at TDC during the test, then of course 100% leakage would occur.

For some reason, I can't make the leap from "engine not turning over" to "100% leak-down test failure" straight away... there has to be more to the story... either the engine "was" turning over (and was spinning fast due to loss of compression, and the leak-down test revealed a very high percentage of air loss), or the testing was invalid... or I'm still out in the Kudzu somewhere.

I'm interested in hearing the resolution to this and the testing methodology employed to get there.


Regards,

Whit
 
Things that make you go "Hmmmm?!?"

What would most likely cause this catastrophic failure....timing belt. But "They took off the valve covers and couldn't see any issues there"... Well, you COULD have a bunch of bent valves but that's not a common problem with these engines.

Sounds fishy to me!

Many service departments now have fiber optic scopes that can be inserted into the engine for a quick inspection without pulling the heads.

Whatever they find, I would want to see.

Good Luck and keep us posted!!
 
EdsST said:
The starter was turning but the engine wasn't turning over (my first thought was the starter solinoid wasn't engaging the flywheel).
Click to expand...

One more thought in defense of the dealer. It could be that the engine didn't appear to be turning to you because of lack of compression. When it was actually spinning freely. In this case it could have dumped the timing chain and bent all the valves at start up. Did they say if the cams were turning with the valve cover off? I think you said everything looked good inside the valve cover though. Might not be able to detect slightly bent valves.

As others have stated, there may be a communication error.

However if the first statement above is true I stand by my first post.

How many miles on it?

Good Luck
 
I agree with WJBERTRAND. If the suspected rings or valve problem, they should have done compression test, then leakdown test.
 
100% failure on all 4 cylinders?!:eek:

If they performed a leak down test (assuming they actually know how to perform one) they should be able to tell you where the 100% leakage is going.

It's either going to come out the exhaust, back up the intake or, out the valve cover breather (crankcase.) Does the service department own a stethoscope or a piece of hose?

One end of the hose near your ear, the other end to listen for escaping air.

You don't need to pull a head to figure that out.

Once they know where the leakage is going, then they call you for further tear down dollar$.
 
They did a compression test first - from what I understand that's what led them to the leak down test. The bike just turned over 55,000mi

Too late heads are pulled - as far as what was turning I guess I could have explained that better. From my limited knowledge it sounded like the starter motor was turning, but not the engine. Well I think the engine was turning, you just didn't hear the normal sounds before it starts - that why I said it sounded like the engine wasn't turning.

I talked to the service rep (the tech is off today) and while he wouldn't say much without talking to the tech it did say there was a lot of carbon build up on the heads. I asked what would cause that and the answer was gas - I run premium (never have had a fuel problem).

So right now I'm waiting patiently
 
Sounds like its time to find a different mechanic.
Ask them during the leak down test where the air was coming out at. If its coming out the intake or exhaust or crankcase. That will tell you where the problem is.
 
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