Took it to the track today, fuel dumping out in front of LR tire?

R

robertcope

Contributing Member
Joined
30 December 2016
Messages
119
Location
Houston, TX
Recently purchased a a '92 that is fairly stock. I pulled off the track, parked the car, and smelled fuel. Looked under it and fuel was literally pouring out from behind the driver's seat, I guess where the EVAP canister is. I've had it on track a couple of times before and have not had this issue. Today was warmer than the previous track days and I'm getting used to the car, so I may have been pushing harder than before, too.

I've searched and only found one thread that sounded similar but it had no answer: http://www.nsxprime.com/forum/showthread.php/68485-Evap-Cannister-fuel-leak

I opened the fuel cap and the tank had plenty of pressure in it, for whatever that's worth.

I'll put it up on jack stands and take a look at it tomorrow. Hopefully it is obvious, but I'm guessing it won't be.

robert
 
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Well that's too bad, but it could have been a lot worse! Since there's good pressure in the tank, my guess would be one of the hoses along the fuel line. There are quite a few and they've got some years on them.

Here's a link to the exploded parts view. Hope it something easily accessed and remedied!

AJ

https://www.acurapartswarehouse.com/oem/acura~tank~fuel~17500-sl0-a33.html
 
Yeah, there's a lot of potential leaks in there, for sure. As you mention, it's all really old. I'm tempted to drop the tank and just refresh all of it. Heck, maybe even a fuel pump for good measure.

robert
 
I haven't! I drove the car on Saturday until the tank is nearly empty. I have a bunch of the gaskets and other fuel tank stuff on order[1] and have found a local company that will rebuild the pump-to-filter line for me for $75. As soon as the parts are shipped, I'll start tearing it down. Don't worry, I plan to take pictures and document what I've found.

robert

[1] 17574-SE0-000, 37801-SV4-L01, 95001-55008-60M, 90428-PD6-003, 17570-SL0-013, 94109-12000, 17370-SL0-003, 17371-SM4-A02
 
Parts shipped and should be here next Tuesday. I plan to disassemble this weekend, wife and child permitting...

robert
 
It took about two hours to get the tank out this morning. Nothing really hard about it. Unfortunately, I also don't really see any obvious signs of a leak, bad hose, etc.

Album here: https://imgur.com/a/9zmis

robert
 
One thing I found after pulling the tank was that the charcoal canister vent is right behind the fuel tank approximately where the fuel was leaking from. I decided to test the two-way valve since it is the only path from the fuel tank to the charcoal canister, and as best as I can tell, it is not functional (failed the vacuum test in the workshop manual). Thankfully, it is part of what I ordered.

I have to be honest and admit that I am not entirely sure what the function of the two-way valve is.
 
I've got gaskets for the sender and fuel pump, the three-way joint, the two fuel cut-off valves, and the two-way valve. If that doesn't fix it, I'm not sure what will. I thought about having the pump-to-filter line rebuilt on principle, but it looks to be in okay shape.

I learned today that the cut-off valves are supposed to prevent fuel from getting into the EVAP system. It'll be interesting to see if they're working when I pull them out.
 
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Replaced all the parts on the tank today at lunch.

I tested the cut-off valves in a glass of water. I was surprised at how deep I had to submerge them before they actually cut off. One of them seemed kind of sticky, but it did work.

Hopefully I'll have a chance soon to get the tank back in!
 
So still nothing obvious? I had a serious fuel leak with my tow vehicle once. It turned out it was a small split in the rubber fuel filler neck which only leaked when I filled it up that one time. But it did POUR out. Maybe it's the same thing which only shows up when you're thrashing it around the track and it's coming back up the tube? Just a thought!

AJ
 
Yeah, so far nothing conclusive. I forgot to mention that also tested the two-way valve and it _appeared_ to fail the test. That said, I'm not sure how that would really effect anything as fuel shouldn't be able to get into the system via the fuel cut-off valves in the first place.

I've inspected all of the rubber lines and have not found anything. Also, remember that the system had pressure in it when I opened the gas cap. I'm assuming that if it was a filler neck or similar line, there wouldn't have been pressure. Of course, I still inspected those lines.

Very frustrating, really. I figure there is a high chance that I put it back together and still have a problem.
 
Put the tank back in at lunch today. I was expecting it to be a pain, but it was actually very easy. Took about 45 minutes with me stopping plenty of times to make sure the various hoses were doing the right things, nothing was being crushed, etc.
 
Got the rest of the car back together over the last few days. Finally fired it up today. Took it around the block, took it to lunch, and so far no issues. I didn't expect any, but at least I seem to have put it back together correctly...



While it was down, I took the front seat out and replaced the lower cushion with a much thinner bit of foam. Looks pretty good and feels great. I should be able to find a decent seating position with my helmet on now.

kUPlziml.jpg
 
Great job Robert. Congrats.
Looking forward to your next track session update. Speaking of track days, we held our first PDX of 2017 on the Summit Point Main in WV, my home track (I've been the co chief of grid/tech for 10 years and raced my MR2 in ITA & ITB in SCCA Club Racing for 25 years). My original plan was to bring my NSX up today for a few gentle shake down laps, but, long story short, it was 18 degrees overnight Friday and Saturday and never got above 30 Saturday, so I left her in the warm garage and care of Ben Schaffer, the "NSX Whisperer" here in MD. My neighbor came up to play with his new toy today, so I did get to run his 2003 Porsche Carrera for a session, just to show him the line, etc, and scare him just a little at 7/10ths. haha
Good Luck!
AJ
 
One nice thing about Texas, it's very rare we have a track day that cold! But we do have plenty that are damn hot. Sounds like ya'll had some fun, anyhow!

Not sure when I'm going to get a chance to get back on track. It'll be a few weekends at the very least. :(
 
I took the car out to Texas World Speedway today. No fuel issues. No issues at all, actually. Such an amazing car to drive.

 
That's great to see, Robert. You must have a magic touch. Congrats.
BTW are any of you TX NSX guys/gals going to attend the IMSA race at COTA on 5.6? My wife and I are flying down to visit our son in Dallas the previous weekend and then following our noses down to Austin and planning to go to watch the race. It would be fun to catch up with some fellow race enthusiasts...
 
Well, shoot. I've had the car on track plenty of times since then without issue. Today, it started dumping fuel again. It was somewhat warm today, 85F or so. Otherwise, nothing really special about the day. Kinda at a loss as to what the issue could be now.
 
I have a 2000 and the Evap system is quite different than on the early cars so I can't do an 'eyeballs on' examination, particularly, I don't know where the purge air vent hose is for the evap canister since that doesn't exist on the 2000. That said, did you ever examine the Evap canister and that hose to determine if there was evidence of liquid gas present after one of these events? Having asked the question, I am not sure how liquid gasoline would work its way up to the canister; however, if it can the vent hose from the canister is pretty much the only planned opening in the fuel system to the outside world.

By any chance when you fill your fuel tank, are you one of the fill it up to the top of the filler neck people? If so, that might get fuel levels high enough to allow liquid gasoline to enter the purge system and accumulate in the canister. That is about the only way that I figure that I figure that you get gas 'up there'. Did you by any chance do the vacuum measurement on the canister purge air hose (vent line) as described in the service manual? I am wondering if there is a possibility that the activated carbon has become plugged or saturated with gasoline resulting in a slight negative pressure in the fuel system causing gasoline to somehow be drawn up the evap line - I am really reaching for possibilities here!
 
Which side of the engine firewall is it dripping down from? The gas tank side or the engine side? Can you get a mirror under there to see if it's coming from the tank sender/return?

All these old OEM rubber hoses suddenly being stressed for pump replacements, etc. concerns me. That's why I switched out my fuel lines on my '92.
 
I got the car up on the lift today It's pretty dirty under there and I was hoping to find a "fuel trail" in the muck, but I didn't find any evidence at all. Obviously, that's a pretty major drip, one that I'd expect to make a nice obvious trail in the grime.

I pulled the connections off the canister and it did immediately smell very sharply of gasoline, but then, that's sort of expected even if it is working normally, I would guess. I plugged off the vaccum lines and such to effectively disable the canister.

My plan right now is to take it back out on Sunday and run it hard. At that point, either it won't have an issue, or I'll try and get it up in the air at the track so that I can figure out where it is leaking from.

@Old Guy: I don't overfill my tank. I do fill it up before heading to the track, but it didn't have a problem until it was over half empty. I haven't done any of the tests in the service manual, but plan to at some point.

@Mac Attack: It's coming from approximately where the drain tube from the charcoal canister is located. I don't typically have a jack at the track, so I haven't had a chance to get under it while it's leaking. I replaced most of the lines last year and inspected everything I could get eyes, cameras, mirrors, etc on. That doesn't mean I didn't miss something, obviously.
 
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Be careful with the lines that you plug off. Remember that the line from the canister to the gas tank is the vent line for the gas tank. Plug that line off and air has no way of entering the tank to make up for the gas that is used up. Draw the gas down enough and you will create a vacuum in the tank and your pump will struggle to develop adequate fuel pressure leading to fuel starvation and all the bad things that can result from that.

You should be able to pop the line to the tank off and leave it open so that make-up air can get into the tank. Temporarily seal up the port on the canister. You can leave the other lines attached to the canister if you want or block them off. Fix the tank line some place safe or extend it so that if gas is entering the canister via that line, the gas does not end up blowing back onto a hot header. As a test, do your fuel fill to the normal level and then drive around vigorously to see if fuel is sloshing out that line. That would then explain how gas is getting into the canister (assuming that is where it is draining from).
 

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