Tech is stumped. What causes this misfire?

Hopefully these come through. I'd say if there is any hole water could enter, given that the pipe is fully exposed in the wheel well. You can see in the first picture the corrosion on the inside of the pipe from water getting in.

 

And wrt Patrick's point - it appears to be relatively easy to replace the pipe. Don't need to drop the tank or disconnect much. I'm going to see if I can source a replacement pipe, but am confident the rubber repair will be effective for a while. I used rubber rather than metal tape because a) I don't think fuel will come in contact with the repair, because it's on the top just inside the nozzle seal, and b) it's right where the pipe tapers and I needed a flexible tape to cover the taper. The second picture shows that - I cleaned it up and wrapped that area.

 

I'm late to the party, but if a temporary fix to the hole/crack is still in order, may I suggest using a little JB Weld Epoxy patch. Works great.

 

Excellent. Glad we could collaborate on this. I'm pretty confident based on my experience that once you stop any new water from coming in - and it seems clear that you're on the path to achieving that - you can fill up the tank with the recommended dose of additive and within a couple of treated tanks things will be completely back to normal.

 

I am very interested in what caused the 'spiderweb of holes.' If or when the pipe is replaced, it would be helpful if it could be analyzed to identify the root cause. You are in a salted-road area so corrosion is likely.

Pictures would also help so we can check our own. I'm headed out with a flash-light and camera.

• The accumulated road 'dust' is there - will use a vacuum hose and brush to clean it out with the cap on.
• When I take the cap off, I get a strong wiff of gasoline fumes suggesting a slightly higher pressure.
• The rubber ring on the outside looks OK - can you see any evidence of water leaking inside the trunk following the filler tube?
• In North Alabama, we seldom ice the roads so our dirt probably has little salt.

Although I am not fond of recalls, that the fuel filler is involved may be a safety issue. Already, I would expect an emissions issue because the tank pressure should be off due to the air leak. One incident, may not be an issue but two or more might trigger a recall.

Bob Wilson

 

I think those wires and cap are going to be the hardest things to find here ;-)

 

Followup - I've driven more than 2,000 km since patching the filler pipe, and haven't had an emissions DTC, so it seems I've effectively patched the hole. Found new filler pipes available @ US$100 - 150 and will pick one up some time and swap it out myself.

 

2009 Prius, 74k miles
Do you recommend a brand of water remover? I am also experiencing this same issue, all these frustrations the same as mine. When they finally diagnosed, they also found water in the fuel. Cleaned and emptied the tank and the lines and told me to finish the job with water remover. Check engine light, however, is still on. Either way, I've put two bottles of Techron fuel system cleaner in and driven over 1k miles. The dealership claims there is a more powerful product. Curious your opinions.

 

Uh No. Plug wires and cap? Have you looked under a hood of a Prius. If you dont know what you are saying to these people keep that engineering degree in your pocket along with your comments.

 

By the way EGR can produce misfires. Check TSBs my friend and water in the fuel can cause misfires but with you changing most of the fuel components out would solve that so it is most likely not that. Plus I do know on some vehicles the cowl has leaked bad enough to short coils out at times since it would not seal or would drip down and into spark plug tube and cause rust and carbon to form causing premature failure of coild and plugs.

 

Erik Owens, PriusChat poster since all of March 25, 2018 with heaps of abrasive 'tude, reawakens four year old thread to lay some scorn on longtime contributor Bill the Engineer. Awesome.

Bill has, without question, looked under the hood of a Prius ... though perhaps he began the Firebrid some time after those 2014 comments. Might've been a newb then.

Anyway, since the thread's been reawakened, may as well reiterate that this is one of the classics: it's the thread that identified the tendency of Gen 1 fuel tank filler necks to rust out just above the wheel and take on water thrown up in rainstorms, which has allowed numerous members since to identify and solve the resulting misfire problem.

-Chap

 

Not to mention a 2009 (gen 2) owner commenting in the Gen 1 thread.

Does the Gen 1 have an EGR? The Gen 2 doesn’t.

@Meredith12830, hi and welcome to PriusChat.

It may pay to find a suitable thread in one of the Gen 2 forums to tack on to. The other alternative is to start a new thread.

 

Techron is a very good fuel system cleaner. A water remover it is not. Go to an autoparts store and ask for a fuel deicer. Probably there isn't much water in the system, and a good road trip will help cycle it out. A couple of hundred miles will do.

 

Erik didn't reawaken the thread, Meredith did, and Meredith is the one with the 09 Prius. I guess I'm a relative newbie here, too. Criticism is fine, I certainly can take it and even learn from it.

Snarky criticism isn't what Prius Chat is about, tho. At least I hope not.

 

I understand and agree. Good catch on who reawakened the thread, which was really not the focus of my reaction as much as the gratuitous insult, which you'll have noticed was not an isolated lapse if you've seen some of the same posts I have in the last month. If you haven't, then you probably thought my reaction was off the handle, and I apologize.

Anyway, I'd love for this thread to stay mostly about misfires due to rusty fuel filler necks.

-Chap

 

FWIW: The fuel fill neck part is about US$170 (list), but may be available for less with online searching.

Toyota Prius Fuel Filler NeckPart Number: 77201-47051 PIPE SUB-ASSY, FUEL TANK INLET

Alternate part is Spectra Premium FN886 (Rock Auto; although they claim only 4 left).