Thor Vegas misfire

[WilliamVanatti]

New to this site, but thought I would share. My Thor Vegas 2016 25.2 had a check engine light on last week. Put my OBD 2 code reader on it. Codes PO300, ( multiple misfire) PO 301 ( cylinder #1 misfire) and PO308 ( cylinder#8 misfire). This vehicle was purchased new, has 25000 miles on it. I purchased 2 coils ( $37 each) replaced the 2 spark plugs. Fixed the issue. Very easy to change once the inside doghouse was removed. I did buy 10 spark plugs ( V-10). Now that I’m home I’ll change the other 8.
On a side note: found a long vacuum hose with a plug in it. Thor nor Ford can tell me where it goes. If anyone has the same vehicle and ever has the doghouse cover off inside. Would love to hear where it goes. On the back of the engine right side, two vacuum lines. Top is big. Bottom is small. It’s the small one about 3 feet long. Only person ever worked on it since new was Ford. I tried to use the emergency start and blew 2 of the 4 diodes in the alternator. ($1600 mistake). I’ll never use the emergency start again :-). Bill

[16ACE27]

Originally Posted by WilliamVanatti

I tried to use the emergency start and blew 2 of the 4 diodes in the alternator. ($1600 mistake). I’ll never use the emergency start again :-). Bill

Was the alternator made of gold? Why would doing the same thing as jump starting your engine "blow" diodes in an alternator?

[WilliamVanatti]

Originally Posted by 16ACE27

Was the alternator made of gold? Why would doing the same thing as jump starting your engine "blow" diodes in an alternator?

Actually, when I bought the camper, brought it home, set for 3 months. Went to start it and chassis battery was dead. I used the emergency start and worked great. But battery light wouldn’t go out. Took it to the Ford dealer. Got it covered under warranty. Said the two diodes were blown. Actually didn’t cost me . ( covered). But valuable lesson. ( think when I looked up the price, like $250
I now have a negative blade disconnect on the chassis and on the negative coach batteries. After I hit the store button, I disconnect the coach. 5 years latter and on the originals.

[Chateau_Nomad]

I can't think of any car I've ever had - even in the early 1970s - that needed a sparkplug change before 60,000+ miles. What prompted you to change coils/plugs?

[WilliamVanatti]

I had drive around 700 miles in two days. It was running great. Got off the highway, at a light it started idling rough, then check engine light. Code reader showed 1 & 8 misfire. I was confident it was just the coils, but wanted to pull the plugs to look, figured I would put new ol while at it. Both plugs were pitted. Glad I did buy some…. I’m going to change the other 8 this weekend. Now I’m thinking of carrying around a new coil..

[16ACE27]

Originally Posted by WilliamVanatti

Actually, when I bought the camper, brought it home, set for 3 months. Went to start it and chassis battery was dead. I used the emergency start and worked great. But battery light wouldn’t go out. Took it to the Ford dealer. Got it covered under warranty. Said the two diodes were blown. Actually didn’t cost me . ( covered). But valuable lesson. ( think when I looked up the price, like $250
I now have a negative blade disconnect on the chassis and on the negative coach batteries. After I hit the store button, I disconnect the coach. 5 years latter and on the originals.

So the emergency start worked as it should and now you'll never use it again?

Did it occur to you the bad diodes is what caused the battery to discharge and had nothing to do with the emergency start that you used successfully?

[WilliamVanatti]

Me personally, if my chassis battery is dead, I won’t use the Emergency Start. I’ll swap a battery out of the step or replace it.
Secondly, Nope not that smart :-).

[Judge]

Originally Posted by Chateau_Nomad

I can't think of any car I've ever had - even in the early 1970s - that needed a sparkplug change before 60,000+ miles. What prompted you to change coils/plugs?

This is a long story but somewhat relevant to your comment.....

I have a 2002 Lexus ES300 that only has 50,000 miles on it. The car has been babied and still in almost showroom condition. It uses Iridium plugs good for 100,000 miles.

Back in March the CEL started flashing and it started running very rough. Thought it might have been bad gas at first. I have a higher end OBDII scanner and the code was for a Cylinder 3 Misfire. Unfortunately cylinder 3 is the hardest to reach. Since it is FWD and engineris sideways cylinder 3 is in the middle next to the firewall.

After doing some research it seemed like the coil pack was the culprit. Toyota uses indivisual coil packs that sit on top of the spark plugs. Everything I read said I had to remove the intake plenum to get to it, which was a fair amount of work. After watching a dozen videos I decided to try and replace the coil pack without removing the plenum.

It wasn't easy but I managed to do it. I was also going to change the plug while I was in there but I was worried about breaking it off and then having trouble getting it out because it was so tight to work in there with the plenum still installed. Plus.... I figured the plugs should be fine for another 50,000 miles at least.

I reset the code.... fired it up.... two minutes later the CEL was back.

I then thought it could be a bad fuel injector after doing more research. I watched some more videos on how to use my scanner to determine if a misfire is fuel or spark related using some of the advanced functions.

Long story short the advanced functions of my scanner led me back to a spark issue. I ordered another coil pack (in case the first one I got was bad one)... two new spark plugs.... and a special socket to get back into tight spaces.

The second time around was a little easier knowing how to work back in the tight space. I managed to get the plug out so I installed the new one, second new coil pack and got things back together.

I reset the code.... fired it up.... and no CEL! I took it for a test drive and it was back to normal.

Of course I wanted to know if it was the coil pack or plug. The plug looked fine. So I first took the coil pack and the other new spark plug, connected it to the Cylinder 2 wiring since it was easy to get to and then grounded the plug against the engine block. The new plug fired fine with the coil pack.

Then I put the original spark plug into the coil pack and grounded it to the engine block...... and nothing. No spark.... not even an intermittent spark.

The insulator wasn't cracked. The tip wasn't broken. The plug looked fairly normal for a fuel injected car with 50K on it.

In 40 years of doing a lot of my own engine work across cars, snowmobiles, lawn equipment, etc., I have never seen a spark plug just die like this one did.... especially one rated for 100,000 miles

As they say.... you learn something new every day.

[WilliamVanatti]

Wow, I’ve rebuilt 3 old cars just for fun. 51,57& 73. Nothing like the old stuff. Easy to figure out. This new stuff is way above my pay grade. I was extremely hesitant to dig into it myself on the V-10. Didn’t want to throw money at something I wasn’t sure was the issue. On the v -10 on my Vegas , hardest part was laying on the carpet in the A/c drinking my coffee at 4am. :-). Sounds like you had a really knuckle buster going on. Mine was extremely easy. My intent was to post so if any other users on here run into the issue. Don’t be intimidated. 8mm socket to remove coil an a sparkplug socket …. Glad you got yours solved. Frustrating at the moment.

[mcr1010]

I had the same problem as OP the other day with code P0300 and P0304 coming up on a trip. I am now in Eureka, CA staying parked at a relatives house in yard for a week or so. Not sure I want to get into chasing the problem down and wondered if anyone can recommend reliable place near here to have it checked?
Thanks