Community Forums

Wbonsell · 10-02-2016, 04:20 PM

Our Siena is built on a late '08 Workhorse chassis. It has 23K miles and has performed perfectly since acquiring it in Feb of this year. Towing our Jeep it will do an easy 50mph up most grades pulling bout 3800rpm or so.

Today on our run down from Portland to Grants Pass, OR and in quite a bit of rain, I noticed, what at first was a bit of a miss at higher RPM's and then every once in a while a drop in power. One time barely able to do 3K rpm and a speed of slightly under 40 on a 6% grade. No check engine light. We gassed up in Portland and after pulling out of a rest stop some 90 miles in I did notice a check engine light but the coach was running normally, though no hills yet. I pulled over to check the gas cap (can't pump your own gas in Oregon) to make sure the young kid put it on correctly. Unscrewed the cap and tightened it back on...presto - no check engine light and it remained off the final 130 miles of our trip.

I am wondering if water could have possibly shorted out one of the wires or plugs causing the misfire. Bad gas or water in the gas? We are here for a couple of days before heading to Sacramento but worried about this issue. Anyone else have experience with such a problem? And again, no check engine light has come on after the gas cap problem.

Thanks....

70ChevelleSS · 10-02-2016, 04:50 PM

You may have been sucking water into the engine through the air filter snorkel. Haven't experienced it but others have reported the problem. Depends on where the air inlet is located and the grill opening on front of MH.

George Z · 10-02-2016, 06:04 PM

Agree with 70ChevelleSS, rain water in the air intake

vettenuts · 10-02-2016, 07:38 PM

Yep, had the same thing happen. Replace the filter, clean the MAF, seal the hood and seal the air box. I used a ribbed self sticking foam tape from Home Depot to seal the hood. A little tricky to close the hood (baby powder helps) but it sure keeps the rain out. There are photos in this section of the forum on how to seal the air box.

Wbonsell · 10-02-2016, 10:22 PM

Have done a bit of research since the post and seems this water entering the snorkel may very well be the issue. Searched the threads on sealing the air box but coming with nothing. Will have to take a look at my set up in the morning and see what I can do. thanks.

**JohnRR** · 10-02-2016, 11:08 PM

I had the same thing happen to me once in a heavy downpour trying to pull a hill on I95 in Connecticut it went away shortly there after and has never came back since, but I'm betting it will happen again under the same circumstances from reading different threads about it here.

cef2lion · 10-03-2016, 06:14 AM

I had an issue this past Saturday that was similar. I was just going to search a bit and saw this thread right away. I have an 2004 Adventurer with 39K. Has always ran great. On Saturday I went to a football game and it was raining heavy. First 40 minutes it ran perfect. I stopped and topped off with gas and got on the 4 lane. It started to miss slightly on grades or under load. Not too bad. On the way home it got worse. I had a steep grade off the 4 lane to home. It struggled to get up. I downshifted and keep the RPMs up. Was worried I wasn't going to get it home. No check engine light and gas cap tight. I have the fuel filter adapter to use the GF652 filters and change it each year but not this year. Going to do that. I'm going to check and change the air filter as that thought crossed my mind and confirm it reading this thread. I'm also going to inspect and maybe replace the plugs and look at the plug wires. I go back to Saturday and the issue starting right after I gassed up. The generator was missing a beat every once in awhile during the day. Makes me wonder if I got bad gas. I had about half a tank when I filled up.

Wbonsell · 10-03-2016, 08:40 AM

Quote:

Originally Posted by cef2lion

I had an issue this past Saturday that was similar. I was just going to search a bit and saw this thread right away. I have an 2004 Adventurer with 39K. Has always ran great. On Saturday I went to a football game and it was raining heavy. First 40 minutes it ran perfect. I stopped and topped off with gas and got on the 4 lane. It started to miss slightly on grades or under load. Not too bad. On the way home it got worse. I had a steep grade off the 4 lane to home. It struggled to get up. I downshifted and keep the RPMs up. Was worried I wasn't going to get it home. No check engine light and gas cap tight. I have the fuel filter adapter to use the GF652 filters and change it each year but not this year. Going to do that. I'm going to check and change the air filter as that thought crossed my mind and confirm it reading this thread. I'm also going to inspect and maybe replace the plugs and look at the plug wires. I go back to Saturday and the issue starting right after I gassed up. The generator was missing a beat every once in awhile during the day. Makes me wonder if I got bad gas. I had about half a tank when I filled up.

Almost the same post as my original. This was the first time I had the coach out in the rain and was heading south directly into the oncoming front which in the NW always come from the SW. It was initially a very small missing which gradually increased to where I couldn't keep the RPM's above 3K. Thought I was back in the older Bounder. As we continued south the rain subsided and it began to run a bit better but not completely normal.

From what I have researched it seems the paper filter gets wet and takes a while to dry out. I'm also going to look at the front access panel and see if the top or bottom lines up with the snorkel. Rain could be running down the front and then being blown directly into the snorkel ending up in the air filter I would suspect. Research shows these 8.1's require a ton of air and anything which interferes with that will result in a loss of power as more demand is placed on the engine.

I'm doubtful at 23K that plugs, wires or gas filter is the culprit. Just might have to stay away from the rain...hence our mad dash South!!

cef2lion · 10-03-2016, 08:49 AM

I was driving directly into the driving rain. Prior to that it wasn't raining that hard and that was about when I gassed up and got onto the 4 lane and the driving rain. Wish I would have given the air filter a thought I could have checked it while I was parked for the game. I have a spare air filter I carry. But it never stopped raining all day and if that was the issue the spare would have gotten wet as well. It rain most of yesterday so had no time to check anything out. I'm going to check the air filter out tonight but it might have dried out. I think you are correct that the 8.1 needs lots air. If I was on the flat it would be ok. If I asked it to do anymore work it started bucking. With the amount of rain we got I would bet a good bit got into the snorkel. My wires from what I could see look ok. Wish I would have looked at the engine while it was running and wet to see if I saw any sparking. Never had the plugs out as yet. I'm leaning towards water being ingested into the snorkel. I'm hoping the filter proves to still be wet or damp.

Wbonsell · 10-03-2016, 09:08 AM

Even after the problem ascending a grade, it would run perfectly at 60mph in 6th gear at 2K rpm's. It was only as more demand was placed on the engine. Would think bad wires or plugs would make even normal 60 at 2K problematic.

I'm hoping the airbox is easily accessible as I may try and replace it. Someone said the air filter is the same as a big block 2004 Corvette....

cef2lion · 10-03-2016, 10:30 AM

My airbox is easy to get to on my W22 Adventurer. Right inside front wheel well. Turn the wheel and easy access. The snorkel sits above the airbox looking forward. I'm thinking water off the front wheel could get tossed forward towards the snorkel as well.

Mine would smooth out on the flats as well and run normal as long as I didn't ask anything of it. Soon as I did it started to buck or miss.

Tom17 · 10-03-2016, 01:28 PM

I have a 2004 W22 chassis under a Newmar Scottsdale that did the same thing. Even threw a MAF code. I found a Newmar service bulletin that says to remove the air box and seal the inside around the front fitting where the hose attaches to it. That fitting slides into the larger front air box piece and is held in place by a plastic push pin. Mine had some significant gaps where water could be sucked in. Was obvious that the filter had gotten wet. Also cleaned the MAF sensor while I had the box off.

Tom17 · 10-03-2016, 01:50 PM

Here is the Newmar bulletin.

cef2lion · 10-04-2016, 06:27 AM

Thanks for the bulletin. Interesting on the water shield (P/N 41281) Like to add that to mine. Going to check my air box out for gaps. I pulled the air filter last night. I set it on the counter in the RV while I got my spare air filter out. When I lifted the filter off the counter there was water drops on the counter. The ends of the filter were stained pink. I put in my spare filter and will take it for a test ride this week.