Issue with Engine compression 2015 Winnebago Brave 26a

[Jus1084]

Hello all,

1st time posting and looking for some advice/help.

Recently on a trip from VT to MI one of the bolts on our manifold broke which created a good deal of noise. Also the check engine light came on which I attributed to the manifold, however got the bolt fixed and check engine remained.

The problem presents when traveling on any type of grade when the coach downshifts the RPMs climb but there is no power (on Michigan hills when usually climbing Vermont mountains with plenty of juice). Found myself cruising up hills at 45-55 mph with pedal all the way down to maintain speed.

Diagnostic testing showed misfire codes 300, 306, 316 which was initial addressed with new plug and coil on 6th cylinder. Issue still remains so a compression test was performed and showed low compression only on the 6th cylinder.

I have an appointment with a truck repair shop next week to dig in more and see what they can do since we had a cross country tripped planned the next few weeks.

Any advice, guidance, recommendations, or shared experience would be greatly appreciated. Stats below

2015 Winnebago Brave 26a
Ford V10 Triton engine
32,500 miles

Justin

[Morich]

First thought that may be a totally wrong idea and a total bummer?
When I see low compression on one cyclinder, I think of blown gaskets. Head gasket perhaps as that will often make a real noise as the piston fires out the side to be heard instead of into the muffler? Other gaskets to leak compression like manifold gasket?
That also reduces the power a great deal as that cylinder is no longer able to get full value out of firing.
Can be bad or even worse but this is not a time to take my thoughts as correct until proven.
Changing parts because the computer told them to? Not the best way to save you money? Maybe they should eat those parts and admit they did not test too well before jumping in?
Just my thoughts and open to being wrong!

[bigb]

I saw your post over at iRV2 as well. Low on one cyl could be a bent or otherwise sticking valve, usually head gaskets fail between two cylinders making two equally low cylinders. Not that it couldn't blow out the side but I've never seen that.
It could also be a faulty diagnosis. Was it a mechanical compression test or a cylinder contribution test?

There have been more than a few total failures of low mileage Triton V-10s on these forums probably due to the sheer number of them out there so brace yourselves just in case. Really hope not but you should be aware of the possibility. I was kind of surprised when I saw that but then I considered how many were made so the failure rate is probably quite small in actuality. It always starts out just like yours, and coil packs/plugs are changed as a first, easy step but doesn't fix it. The good news is that you got it in the shop before a total failure and possibly it will just be a top end issue, although a lot of shops now don't want to bother with fixing an engine anymore, seems all they want to do is replace them. Probably due to them having to warranty it and because of the lack of mechanics that actually know how to assemble engines anymore. Another thought is an injector, but they should have been able to figure that out when they replaced the coil and plug.

I know the Triton V-10 is supposed to be able to handle pretty high RPMs but is there a chance you could have revved it too high coming down a grade in a lower gear?

Please keep us posted and meanwhile I'll hope for the best for you.

[Jus1084]

Originally Posted by bigb

I saw your post over at iRV2 as well. Low on one cyl could be a bent or otherwise sticking valve, usually head gaskets fail between two cylinders making two equally low cylinders. Not that it couldn't blow out the side but I've never seen that.
It could also be a faulty diagnosis. Was it a mechanical compression test or a cylinder contribution test?

There have been more than a few total failures of low mileage Triton V-10s on these forums probably due to the sheer number of them out there so brace yourselves just in case. Really hope not but you should be aware of the possibility. I was kind of surprised when I saw that but then I considered how many were made so the failure rate is probably quite small in actuality. It always starts out just like yours, and coil packs/plugs are changed as a first, easy step but doesn't fix it. The good news is that you got it in the shop before a total failure and possibly it will just be a top end issue, although a lot of shops now don't want to bother with fixing an engine anymore, seems all they want to do is replace them. Probably due to them having to warranty it and because of the lack of mechanics that actually know how to assemble engines anymore. Another thought is an injector, but they should have been able to figure that out when the replaced the coil and plug.

I know the Triton V-10 is supposed to be able to handle pretty high RPMs but is there a chance you could have revved it too high coming down a grade in a lower gear?

Please keep us posted and meanwhile I'll hope for the best for you.

Thanks for the reply. I have been reading many of the posts/forums you mentioned and bracing myself for the potential of engine failure outside of warranty.

It was not the mechanical comp test due to the shop not having the appropriate tool to perform. They used the OBD2 to perform the test with new 6th coil and plug moved to different cylinder .

Unfortunately still have to drive it an hour and half to the shop that can take a look on Monday.

There was no event that I recall hitting high rpm’s down a grade. May have hit a few with climbs but nothing out of the ordinary as I tend to baby the engine.

[bigb]

Originally Posted by Jus1084

Thanks for the reply. I have been reading many of the posts/forums you mentioned and bracing myself for the potential of engine failure outside of warranty.

It was not the mechanical comp test due to the shop not having the appropriate tool to perform. They used the OBD2 to perform the test with new 6th coil and plug moved to different cylinder .

Unfortunately still have to drive it an hour and half to the shop that can take a look on Monday.

There was no event that I recall hitting high rpm’s down a grade. May have hit a few with climbs but nothing out of the ordinary as I tend to baby the engine.

The ECM won't allow you to over-rev under power but coming down hill in too low of a gear can allow it to happen. It won't allow you to shift too low for your road speed when descending but if you start out slow in a low gear and increase speed it's possible it may over-rev. I've been told the newer transmissions may upshift regardless but can't say for sure and I've never found anyone who could verify that or anyone brave enough to put that to the test.

[Eagle5]

Hi Justin,
Since you broke an exhaust manifold bolt and the 306 error occurred at the same time, it makes me think that it is the exhaust valve on number six. With a manifold cracked-open, it could have cold-shocked #6 exhaust valve.
If you remove all ten coil leads, you should be able to detect a lump when you crank-over the engine, indicated low compression on a cylinder.
I would recommend you buy a remanufactured long-block, if this is the case. I believe they are running about $5K now, plus installation. I also recommend running 0W-40 oil, and keeping the engine speed below 4,000 rpm.
Welcome to the forum.
Eagle5