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One of the main causes of engine stalls

 
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Old 02-25-2015, 02:44 PM
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One of the main causes of engine stalls

I don't remember if anyone posted a picture of this to accompany the explanation, so here goes.

Inside the gas tank is a fuel vapor recirculation hose. A check valve regulates the air pressure inside the gas tank and excess pressure is relieved by venting air through the recirc hose. This air contains fuel vapor, so it must be vented back into the engine so it can be burned off and processed through the emissions system.

The problem is that the hose in the fuel tank is a bit long and that creates a "droop" in the hose prior to the valve. The droop creates a point of friction between the hose and the valve's nipple. The end of the nipple rubs against the inside of the hose as the car moves around and over time the hose will split at that friction point. Here's a pic to show what I mean:



Once split open, nothing prevents fuel from getting into the hose. Conditions have to be ideal-ish for it to suck up enough fuel, but it does happen. If enough fuel gets sucked up, it will stall the engine. The bandaid solution is to keep the gas tank no more than half full so fuel can't reach the hose. But the fix isn't that difficult.

In the rear hatch is a bit of a shelf - that's your gas tank. Remove the carpeting and you'll see a round access port with a whole bunch of bolts keeping it in place. Open that up and you're inside your gas tank.

IF YOU DO THIS YOURSELF BE VERY CAREFUL. If you attempt this, you do so with no guarantees expressed or implied from me - I'm just a dude on the internet.
You're working with a tank of gas - it's explodey. Keep flames, sparks, etc of all sorts far away.
You can only get one hand into the gas tank at a time - you better be good with your fingers because you have to do everything one-handed in there.
Do not get anything into the tank - no debris, dirt, walnut shells, small children, etc.
There is a foam gasket sealing the access port. It tears very, very easily. I'd highly recommend having a new one on hand before doing this.

1) Remove the clamp and hose from the valve (pictured above).
2) Cut any broken hose away so you have a clean end.
3) Connect the shortened hose back onto the valve and use a new clamp to secure it.
4) Use a new foam gasket and reseal the access port.
5) Reinstall your carpeting. Great Success.

The now-shorter hose will have less "droop" which will in turn alleviate the rubbing issue and greatly reduce the chance of another hose split.

My local dealership's wondertech Tim did this for me pretty quickly, I don't think it took even an hour.
 

Last edited by telum01; 07-16-2015 at 01:12 PM.
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Old 02-25-2015, 06:17 PM
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A link to this needs to go in the faq thread. Very informative. Thanx.
 
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Old 02-25-2015, 08:50 PM
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Hope it helps some people!

I'll add it the FAQ tomorrow if zvez hasn't done it by then.
 
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Old 02-26-2015, 03:41 AM
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Chris hasn't been around in months. I don't know where he's been. Hope he's ok.
 
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Old 02-26-2015, 09:53 AM
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wow, thank you very much for the tip
 
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Old 02-26-2015, 06:00 PM
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Thanks for the write up! The forum appreciates it! Nice write up and picture.
 
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Old 03-01-2015, 08:15 PM
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Awesome Info! I will do this to mine before it tears to line. An ounce of prevention..... Thanks!
 
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Old 03-10-2015, 05:30 AM
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Quick update to this:

My car is running much better at low-RPM now, in all gears. Previously, the car would stutter and jerk a bit at low RPMs. Now it's nice and smooth. This was at any fuel level, so I don't think it was because extra fuel was being dumped into the engine. However - I'm guessing based on what I'm seeing that the car "learned" to drive like crap due to the fueling issue with the bad recirc line. After clearing all the codes it's bad to running nicely. OR: the excessive fuel vapors from the open recirc line was causing it to run poorly.

Either way, the car is running much, much better now!
 
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Old 03-10-2015, 09:51 AM
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I haven't had this problem yet but it's reassuring to know what the fix is. Thanks for posting!!
 
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Old 03-12-2015, 11:56 AM
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Great photo

I can imagine the trouble having gotten that photo! The effort is greatly appreciated! Am printing it out and filing in the appropriate place in my repair manual.
Wish there was a similar photo to resolve my SRS airbag code 0116 and CFFF. (Open circuit, left side, won't reset)

Originally Posted by telum01 View Post
I don't remember if anyone posted a picture of this to accompany the explanation, so here goes.

Inside the gas tank is a fuel vapor recirculation hose. A check valve regulates the air pressure inside the gas tank and excess pressure is relieved by venting air through the recirc hose. This air contains fuel vapor, so it must be vented back into the engine so it can be burned off and processed through the emissions system.

The problem is that the hose in the fuel tank is a bit long and that creates a "droop" in the hose prior to the valve. The droop creates a point of friction between the hose and the valve's nipple. The end of the nipple rubs against the inside of the hose as the car moves around and over time the hose will split at that friction point. Here's a pic to show what I mean:



Once split open, nothing prevents fuel from getting into the hose. Conditions have to be ideal-ish for it to suck up enough fuel, but it does happen. If enough fuel gets sucked up, it will stall the engine. The bandaid solution is to keep the gas tank no more than half full so fuel can't reach the hose. But the fix isn't that difficult.

In the rear hatch is a bit of a shelf - that's your gas tank. Remove the carpeting and you'll see a round access port with a whole bunch of bolts keeping it in place. Open that up and you're inside your gas tank.

IF YOU DO THIS YOURSELF BE VERY CAREFUL. If you attempt this, you do so with no guarantees expressed or implied from me - I'm just a dude on the internet.
You're working with a tank of gas - it's explodey. Keep flames, sparks, etc of all sorts far away.
You can only get one hand into the gas tank at a time - you better be good with your fingers because you have to do everything one-handed in there.
Do not get anything into the tank - no debris, dirt, walnut shells, small children, etc.
There is a foam gasket sealing the access port. It tears very, very easily. I'd highly recommend having a new one on hand before doing this.

1) Remove the clamp and hose from the valve (pictured above).
2) Cut any broken hose away so you have a clean end.
3) Connect the shortened hose back onto the valve and use a new clamp to secure it.
4) Use a new foam gasket and reseal the access port.
5) Reinstall your carpeting. Great Success.

The now-shorter hose will have less "droop" which will in turn alleviate the rubbing issue and greatly reduce the chance of another hose split.

My local dealership's wondertech Tim did this for me pretty quickly, I don't think it took even an hour.
 
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Old 03-12-2015, 02:19 PM
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Originally Posted by Christiaan0922 View Post
I can imagine the trouble having gotten that photo! The effort is greatly appreciated! Am printing it out and filing in the appropriate place in my repair manual.
Wish there was a similar photo to resolve my SRS airbag code 0116 and CFFF. (Open circuit, left side, won't reset)
I've got an awesome tech at my local AM dealership, he was kind enough to take the pic for me. And yeah, a picture says a thousand words! It's one of the reasons I try to snap some shots for a DIY guide whenever I work on something.
 
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Old 08-31-2015, 02:55 PM
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Cool newer generations may have already had this revised/repaired

I have a 2012 V8 vantage--I've been experiencing these mysterious stall problems--even though they only happen perhaps 2x a month. It's been starting to concern me so I took a stab at this fix.

After finagling around with the carpets for a bit ( you really only need to remove the carpet piece that holds the umbrella, and then proceed to remove the large carpet bolts holding down the shelf portion of your trunk and finally the lower bottom carpet piece.




After I was inside, I noticed my valve device was blue and a bit different since all of the plastic hoses within the gas tank do not use any clamps, they are simply held snug in place over the nipples--this leads me to believe this is a redesign to address the gas valve issue.

I've attached a pic I took using my borescope (not best quality but should be able to distinguish the hose)




Good news: validates that this is not the gas hose issue
Bad news: what the hell is causing my stalls!!

This now has me pursuing a mission--I believe my next step is to figure out what is causing such high oil consumption (.5-1qt per every 500-1000 miles). It could be that large oil amounts are being recirculated into the intake which could overburden the combustion/air-fuel causing the engine to stall. (my hypothesis for now). I have checked my AOS lines and they seem full of sitting oil.
 
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Old 08-31-2015, 06:41 PM
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Originally Posted by telum01 View Post
I don't remember if anyone posted a picture of this to accompany the explanation, so here goes.

Inside the gas tank is a fuel vapor recirculation hose. A check valve regulates the air pressure inside the gas tank and excess pressure is relieved by venting air through the recirc hose. This air contains fuel vapor, so it must be vented back into the engine so it can be burned off and processed through the emissions system.

The problem is that the hose in the fuel tank is a bit long and that creates a "droop" in the hose prior to the valve. The droop creates a point of friction between the hose and the valve's nipple. The end of the nipple rubs against the inside of the hose as the car moves around and over time the hose will split at that friction point. Here's a pic to show what I mean:



Once split open, nothing prevents fuel from getting into the hose. Conditions have to be ideal-ish for it to suck up enough fuel, but it does happen. If enough fuel gets sucked up, it will stall the engine. The bandaid solution is to keep the gas tank no more than half full so fuel can't reach the hose. But the fix isn't that difficult.

In the rear hatch is a bit of a shelf - that's your gas tank. Remove the carpeting and you'll see a round access port with a whole bunch of bolts keeping it in place. Open that up and you're inside your gas tank.

IF YOU DO THIS YOURSELF BE VERY CAREFUL. If you attempt this, you do so with no guarantees expressed or implied from me - I'm just a dude on the internet.
You're working with a tank of gas - it's explodey. Keep flames, sparks, etc of all sorts far away.
You can only get one hand into the gas tank at a time - you better be good with your fingers because you have to do everything one-handed in there.
Do not get anything into the tank - no debris, dirt, walnut shells, small children, etc.
There is a foam gasket sealing the access port. It tears very, very easily. I'd highly recommend having a new one on hand before doing this.

1) Remove the clamp and hose from the valve (pictured above).
2) Cut any broken hose away so you have a clean end.
3) Connect the shortened hose back onto the valve and use a new clamp to secure it.
4) Use a new foam gasket and reseal the access port.
5) Reinstall your carpeting. Great Success.

The now-shorter hose will have less "droop" which will in turn alleviate the rubbing issue and greatly reduce the chance of another hose split.

My local dealership's wondertech Tim did this for me pretty quickly, I don't think it took even an hour.
I actually think the hose swells, which enlarges and creates that loop, also S fail location. My honest opinion is that the wrong hose was used to be soaked in fuel..but again, it's just my opinion so don't think Aston will grant a free repair..LOL

The hose isn't to bad of a fix if you don't have any fuel in the tank(use a fuel candy) and that it's a Coupe(not a roadster)..but this was early cars, don't remember the VIN range, but think 2009+ was different
 
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Old 08-31-2015, 06:48 PM
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Originally Posted by mrgylex View Post
I have a 2012 V8 vantage--I've been experiencing these mysterious stall problems--even though they only happen perhaps 2x a month. It's been starting to concern me so I took a stab at this fix.

After finagling around with the carpets for a bit ( you really only need to remove the carpet piece that holds the umbrella, and then proceed to remove the large carpet bolts holding down the shelf portion of your trunk and finally the lower bottom carpet piece.




After I was inside, I noticed my valve device was blue and a bit different since all of the plastic hoses within the gas tank do not use any clamps, they are simply held snug in place over the nipples--this leads me to believe this is a redesign to address the gas valve issue.

I've attached a pic I took using my borescope (not best quality but should be able to distinguish the hose)




Good news: validates that this is not the gas hose issue
Bad news: what the hell is causing my stalls!!

This now has me pursuing a mission--I believe my next step is to figure out what is causing such high oil consumption (.5-1qt per every 500-1000 miles). It could be that large oil amounts are being recirculated into the intake which could overburden the combustion/air-fuel causing the engine to stall. (my hypothesis for now). I have checked my AOS lines and they seem full of sitting oil.
Oil enters through the PCV and is supposed to drain back via the oil/air separator..just this perfect world doesn't happen entirely as engineered. .. Although if you have large amounts of oil in the lines and no external oil leaks to show possible excess crank pressure..I'd inspect the PCV and make sure its not stuck, although as a diy'r you wouldn't be able to inspect via preassure at home, all you can do is see if the valve is soaked with oil..so a shop visit would be required, unless you just want to buy one and put it on yourself
 
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Old 09-01-2015, 08:08 AM
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So I removed the AOS,PCV valve, and most of the hoses from the engines recirculation system. Lots and lots of sitting oil within the lines--this clearly shouldnt be the case since at most this should just be circulating back vapors. (crankcase->AOS->PCV->intake)

I called my local Aston Martin Dealership--they explain the AOS is always held in stock since they tend to fail and are cheap to replace ($43). As for the PCV valve the head technician said he never sees this part fail, and they don't keep them in stock, it's a special order item at $243. This leads me to believe my AOS has failed and I will be replacing today.

I wish there was a better way to test these parts but it seems to alwas be a reactive fix rather then proactive. I am hoping this addresses my stall and oil consumption issue. Will follow up in a few days after the fix.
 

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