Mr. IROC-Z

iTrader: (1)

Damn...that's not good Walnikj! Did you mount it correctly? (the filter part needs to be pointed up towards the top of the car.

walnikj

Yes. I plan on getting a new charcoal can again soon and then I'll try it again.

alan91z28

Just a quick update on my continued experience and some additional thoughts that might help.

I have several 3rd gens as you can see in my signature. I have this mod running on several of them and in my experience it has continued to be very positive (ie no pressure build up and has resolved hot weather driving on several)

With that said, it can not correct issues that are a result of failing fuel pump / plugged filter, etc...

Over the weekend i just replaced the fuel pump / sender assembly and filter on one of my 3rd gens that is in basically pristine condition with only 31K miles on it. After ~30 years of running and now with ethanol in the fuel there was accumulation of rust debris in tank/filter sock and failure of the pulser, etc and filter plugging. New walboro 255 pump, sender assembly, filter, and back to new running condition

So in my experience I have had very good luck with this valve for pressure related tank issues associated with the evap system failing. Also have had the need to replace pumps, etc on 3rd gens.

What i am doing over time with my fleet is
- Ethanol Free Gas to full extent possible
- Vent mod in addition to / replacing evap
- Renewing tank, pump, sender, filter
- Injectors, regulator, etc

Summer heat can be Beat! We need to enjoy our rides!

walnikj

I plan on trying it again as I believe that it works. I put a new Delco pump in March 2016. I did have less pressure with Tanks valve but my car never stalled while driving until I put the valve in. It had fuel on the valve and it was kind of oily. Weird. Maybe the corn in our fuel?

walnikj

Can anyone tell me if this set up is correct for a 1988 350 TPI? I see some cars where the valve is inline from the gas tank tube on the bottom. I had fuel come from the tank line today. I thought only fumes came from that line to the can.

NoEmissions84TA

iTrader: (1)

Could you have gotten the lines mixed up when you replaced the in-tank pump?

walnikj

No the lines are good to go. My car runs great and is strong.
just the pump whine and pressure from this Florida summer heat. Now I'm wondering if the charcoal can lines are correct from when I got it from the previous owner.

dcjredline

Awesome post! Im going to be ordering this for my 89. I dont experience the stalling issue at all but everytime I take the gas cap off there is alot of pressure in there. I do use 90/10 fuel sometimes and its not real hot here in NY most times. I took the stock valve off today and it was working when I blew into it, I took it apart and cleaned it which didnt seem to loosen it up so replacement will be the ticket. I will try to update when I get the valve and get time to drive it and see if the pressure in the tank is gone.

ETX

So my car has pressure in the gas tank even after sitting for days in the garage. It has been abnormally hot for this time of year and humid.

I had experience the same drivability issues in hot weather and could hear the pump wine. I have a new pump and pump a new fuel filter on.


At any rate I can smell fuel in the garage and when I take the gas cap off i releases a ton of pressure.

Has anyone else had pressure even if the car has sat? If the issue is in the engine compartment with the canister and associated valves will this modification still resolve the issue?

I am guessing the UFO value is shot or needs to be cleaned and I am going to pull it and clean it first.

Of course auto zone has a list of all the parts and no longer carries any of the for the EVAP system.

KCG

iTrader: (1)

Here's how mine is on an '89 IROC. I wasn't 100% sure this was correct either, but the decal I found underhood seemed to confirm it.

Here you can see the top line going towards the intake.



Here the top line is removed and you can see the valve connected to the bottom port of the charcoal cannister and it goes to the steel line down the frame rail to the tank.



And the decal on my hood.

walnikj

So, not long after my last post I added a valve in the line to the tank like you have in your pictures KCG. It's seemed to help, my pump doesn't whine as much even in 100 degree weather. Also, I have two lines from the top of the can with another valve. Since my car has no smog or Cat I'm sure it was moded that way.

Dartht33bagger

I think I may need to try this mod. My gas tank has always had pressure problems. I haven't driven the car in a week and I pulled the gas cap off today to be greeted by thudding sounds coming from the gas tank and pressure being released. I cleaned the UFO valve months ago with no improvement and I think my canister solenoid is bad. No one makes a replacement canister for our cars so this seems like my only possible solution.

Dartht33bagger

I did a test today and figured this out about my situation.

After not driving the car for a week, I let the tank pressure out. The pressure was a lot and I could hear the tank making noise as it removed pressure. Then I drove it 35 miles on the highway to work on a 50 degree day. After parking I removed the gas cap again. Very little pressure released this time and the tank did not make any noise - which seems like what I would expect out of a pressured system.

This is where it gets weird. When I came back to the car after work, I removed the gas cap again to see if any pressure had built up while sitting. To my surprise, there was A LOT more pressure built up than there was earlier in the day when I parked. Not enough to make the tank make noise, but enough to surprise me.

From all of this, it appears that my vent system works correctly when driving. However, when the car idles a lot or when it sits after driving it, the heat from the muffler causes the tank to increase in pressure. Adding the heat pressure onto the normal driving pressure likely causes the massive pressure issue where the tank makes noise when removing the cat.

The tank VVR should fix this issue, but I worry about it smelling like gas for 30 minutes to an hour after I drive it if the muffler heat is truly causing the issue. Additional isolation between the muffler and the gas tank may be the right answer. Apparently the stock heat shields are not enough. This might be what I'm looking for: https://www.summitracing.com/parts/hsp-177101. Cheaper options would be better of course.

scottmoyer

I'm not sure why so many people keep going back to the heat shield issue. My car is bone stock, with the factory catalytic converters and the exhaust. This problem was NOT an issue for 20 years, but is now an issue. The heat shields haven't changed any, nor has the exhaust, in my case. Using a stock car, that's experiencing the same issues as modified cars, will help to eliminate some of the stock components.

Since the fuel system is a loop, there has to be something causing the fuel to not be cooled I believe that a return line, fuel injectors, or vent line are contributing to this problem. As I get the $$ together, I will start replacing vacuum lines, cleaning out the vent lines, replacing 30 year old injectors, etc. These are the logical things to address, not the heat shields that worked for over 20 years.

Dartht33bagger

I guess I'll just try running the VVR valve for the time being and save the UFO valve in case you figure out what the problem is. I've never had the benefit of a stock car for comparison so I'm just working off of what I've read on here. The gas tank above muffler problem seems to make sense to me, but if it hasn't been proven, there isn't much of a point for to shell out the money on insulation.

Bob88GTA

iTrader: (2)

Once again....I been running non-ethanol fuel in my stock 3rd gens, with fully functional vapor canisters and emission systems for over a year. No boiling, no pressure, no vapor lock. In hot, humid Alabama.

85 5.0 TPI
88 5.7 TPI
89 3.8L TTA

scottmoyer

I'm also running non-ethanol gas, but that hasn't changed anything.

I plan on using the vent valve from my other car to see if that helps, but I don't think there'll be any change. If there is even the slightest vacuum leak, due to the vacuum lines being 30 years old, the vapor canister valve may not be opening. Also, the fuel injectors could be an issue due to the seals and such being 30 years old. South Bay Injectors mentioned that the injectors could also be an issue with this problem. Lastly, could the ECM play any part in this? I may need to swap mine out due to an intermittent code 42 that I just recently started getting. All of these could be the culprit.

Bob88GTA

iTrader: (2)

OOPS, I did change out my injectors to SouthBay Bosch III's on the 88, but that was 4 years ago.

Never ending saga for sure. Good luck.

Dartht33bagger

I have new injectors from my engine swap last year, a new fuel pump in late 2013 with maybe 5k miles on it, and have cleaned out my UFO vent. None of that has helped. From my testing over the weekend, I don't think my canister solenoid works but the tank doesn't seem to get super pressurized after a drive. Only after it sits for a while does it get bad. Non-ethanol 92 octane gas around here is crazy expensive at around $3.80/gallon in the winter and $4.29/gallon in the summer. Compare that to what I'm paying for ethanol 87 octane at $2.44/gallon and that is not so persuasive.

Honestly, this wouldn't bother me that much if my gas tank did not form a hairline crack in it earlier this year. I was able to braise the crack and get the tank sealed again, but every time I hear the tank 'thud' when it releases pressure, I'm worried that I'm going to be dropping the tank AGAIN and getting it fixed AGAIN.

ZZ42Fast

iTrader: (2)

Why are you even debating this. Do Alans mod, I did and no pressure ever now.

scottmoyer

The Tank VVR valve does work, for allowing air into the tank and also venting the tank. If you don't want the car smelling like gas, and stinking up your garage, this is not the correct valve. I took my factory valve off and haven't had any issues, but I didn't solve the overall problem. My tank is not venting to the charcoal canister, like it should. It's venting out the open hose. I want the "system" to work as it should. I need to find out if it's a bad valve that has been cleaned, but is still the issue, or is it in the vent lines to the canister, or the return lines to the tank?

Dartht33bagger

In my case where the pressure builds up after the car sits, I don't see how the charcoal canister would help assuming it is working as designed. From my understanding, the pressure relief valve in the canister vent line requires vacuum to open. The vacuum is provided from the canister side of the line, so I'm assuming that the vacuum is provided by the engine through the canister while driving. When the engine is off, where is the vacuum coming from to open the pressure relief valve to the canister?

The VVR valve came yesterday and I am going to put it on my car this weekend. I hope the gas smell isn't too bad because my dog sleeps out in the garage. A real solution would be preferred, so I will be closely watching what Scott does.

Bob88GTA

iTrader: (2)

Good luck!
"I hope the gas smell isn't too bad because my dog sleeps out in the garage"

You might just want to crack your garage door an inch or two...just in case. Don't need to be reading about dead dogs. Just a suggestion.

Dartht33bagger

I have been running the VVR valve for about a month now and it does work. No more tank pressure issues when I remove the gas cap and no thuds from the tank during driving. To the users saying the car will not smell like gas though are pretty far off the mark - at least on my car. The instant I get out of the car after driving it, I can smell gas. Hopefully in the summer with the windows down I won't be able to smell it at stop lights. After driving the car it stinks like gas for 45-60 minutes before the tank stop venting which can be annoying if I get home late at night and need to let the garage air out before I go to bed. In all honestly, the VVR valve will likely be a temporary solution.

In another thread someone said that 88-95 trucks have a canister solenoid that is compatible with the ECM in our cars. My dad has a 89 truck with the canister on it. When the weather warms up I plan to do some experiments with the solenoid on the truck to see if works similar to how ours is supposed to work. Assuming the solenoid works the same, I'm thinking of ordering a solenoid for the trucks and putting it inline between the charcoal canister and the throttle body. This should work because my canister solenoid is stuck open, which would bypass the issue of no longer being able to buy a new canister for these cars.

I'll update this thread whenever I get around to testing this out. If it is possible to get the EVAP system working on my car again without spending a small fortune, I'd love to do it.

IROCgiraffe

iTrader: (3)

I'm interested in looking into this deeper. I've replaced just about everything on my fuel system and still have this stumbling issue once the engine warms up. In the summer once everything is hot, it seems a little sluggish and giving any kind of throttle after sitting at a traffic light makes the engine want to stall.

When I replaced the fuel pump I did soak the UFO valve in a mix of Purple Power and water and it appeared to have cleaned out the filter very well. I'm dying to get this car running right.

GTAguy549

GTAguy549

greenyone

iTrader: (1)

I had the same issue. Tried cleaning the UFO valve with no success. Drilled a tiny hole in the gas cap...which actually worked in that no pressure built up, but it introduced another problem. When I corner hard left with a full tank of gas it was coming up the fill tube and through the vent hole in the cap. I finally went with the VVR valve with no issues other than the gas smell that others have experienced.

I honestly thing the UFO valve, if working correctly combined with exhaust heat is the problem. I've tried UFO valves from 4th gen cars in mine with no success either.

GTAguy549

1989karr

would it be possible to just bypass the vent solenoid (but keep it there to prevent any check engine lights etc...) and route the vent from the tank straight to the motor?

My S-10 has the vent line going straight from the tank to a charcoal canister with no valve on it and direct to the engine.

I assume this would eliminate the vent solenoid issues if it is broken, and maybe the pressure would overcome the UFO valve and force it to let air in the tank if needed?

greenyone

iTrader: (1)

I guess you could...but I'd think that all you are doing is relocating the heavy fuel vapor smell from the tank area to under the hood if you do that. However if the charcoal canister is doing double duty now (acting as the UFO valve in this instance) the smell may not be as bad. Also, I'm not sure how often the purge valve is commanded open by the ecm, so you could potentially have some vacuum related issues if it's always sucking through the canister instead of being commanded open. Maybe somebody with more knowledge can chime in on the normal operation of the canister purge.

I still think the solution to this tank over pressure problem is compound. It's likely a combination of an exhaust component being too close to a fuel line and/or tank and faulty old UFO valves. I've tried multiple used UFO valves on my car and the tank pressure problem persists. If I drive the car (with the tank pressure relieved before driving) then unscrew the cap after I've reached my destination I get the huge 'whoosh' of pressure. If I let the car sit overnight (cold) with the cap tight I get the huge 'whoosh' of pressure if I unscrew the cap in the morning. After replacing the UFO with the previously mentioned Summit Racing roll over valve I get no over pressure in any situation. So I'm at a loss as to what my issue truly is as it builds up pressure even when sitting cold in a garage for 12 hours, but I'm leaning toward the UFO valve with all this in mind.

GeneralDisorder

iTrader: (1)

The system is supposed to be pressurized. That's normal operation. The whole point is that the vapors are trapped and stored in the charcoal canister and the only way that is possible is to keep it a closed system. So pressure is going to build. The UFO valve only lets out pressure if it rises above a pre-determined point - for safety reasons. You will always hear the whoosh of air when you loosen the cap - this is entirely by design.

greenyone

iTrader: (1)

Yes but I believe the issue is over-pressure.. to the point that gas tank expands. I for one would hear the sound of the tanks sheet metal making popping noises with the car (cold) just sitting in the garage not having been run for days sometimes. Before and during all the failed attempts on trying to clean or installing used UFO valves I had to remember to loosen the cap after every drive. The Summit VVR/ROV valve, although not a perfect solution seemed to have solved that issue.

chazman

iTrader: (4)

I've removed my faulty tank vent valve and am just running it without. I've noticed a difference in my screaming fuel pump, but now I think the pump has had enough and even screams when the tank is full. In the 6.5 years I've owned it, the pump would stay quiet until under 1/4 tank. Then under 1/2 tank, now it seems constant.

I feel as if I could have figured it out and removed the vent when I first got the car, I could have saved the pump.

GTAguy549

GeneralDisorder

iTrader: (1)

There's no harm in removing it. Mine was broken when I got the car and I have just left that hose open for three years now. If it's real hot outside and the tank is full and I'm parked on an incline sometimes I get some fuel dribbling out. Otherwise there's no issues at all. I haven't got any of the EVAP system in fact. I tore all that stuff and smog pump and cat out because none of it was any good after an 11 year stretch in a collapsed greenhouse in the woods.

GeneralDisorder

iTrader: (1)

I highly doubt that vented vs closed has anything to do with your fuel pump noises. The original style fuel pumps in these cars just weren't long lived.

chazman

iTrader: (4)

A previous owner replaced it. Who knows which pump thy used?

GeneralDisorder

iTrader: (1)

No way to tell. But there's a lot more cheap junk out there than there is quality parts that last. It's a race to the bottom in terms of price and quality in the automotive aftermarket. When you are ready to swap it out, get a Deatschwerks pump kit for a 1990 C4 Vette. About $100. Excellent quality and virtually silent. I use hundreds of their pumps a year and have never had one come back.

GD

chazman

iTrader: (4)

Wish I knew. I just ordered this Delphi pump from Rock Auto.
https://www.rockauto.com/en/moreinfo...035548&jsn=486

GeneralDisorder

iTrader: (1)

Delphi is probably fine. They are generally a pretty high quality part in the box. Likely to be a Bosch in the box, which is what Deatschwerks uses in their kits I believe. There's not a ton of fuel pump manufacturers out there. Most everyone is rebranding - Delphi is typically OEM quality though. I have bough pump assemblies from them that were just reboxed OEM when I was in a pinch and needed one quicker than I could get from the dealer, etc. Sometimes on the newer stuff we have to replace the whole plastic assemblies because the nipples break off or something else on them gives out that isn't the pump itself.

GD

GeneralDisorder

iTrader: (1)

Huh. If those specs are right..... thats a pathetic little pump. 22 Gallons per hour is like 90 liters per hour. The Deatschwerks ones I use are 265 liters per hour.

I mean - it will work, but at 90 LPH it isn't going to supply more than 250 HP based on my calculations.

GD

chazman

iTrader: (4)

Do you think it was a pump going bad the whole time?

chazman

iTrader: (4)

Should be okay, doubt that car will ever exceed 250 hp.

GeneralDisorder

iTrader: (1)

Entirely possible. Sounds like it's got a bearing going out, etc. I never have had the pleasure of dealing with the original style pumps - all my 3rd gen's have come to be with bad pumps/tanks anyway.

GD

1989karr

Well, I just did this mod, I removed the UFO valve thing I tried sucking on it and it requires a HUGE amount of vacuum to allow air to get in so I'm thinking that's junk. I didn't drill out the bracket in case I need to put it back though, I just plumbed the hose on the opposite side and keep it in place with a hose clam and zip tie.



What I did differently though was I bought a new evap canister filter, cut a piece and shoved it into the vent pat of the valve.and pushed it all the way down so that any air coming in is filtered and any vapor going out is also filtered. . From what I know, the canister is basically performs a similar function to this valve...allowing vapor to vent / passing vacuum / air flow, and that filter helps prevent a gas smell. since the canister stores vapor for a bit.


So far I don't have any issues with a gas smell etc... my car USED to have a huge amount of pressure in the tank even after a couple minutes of idling etc...and removing the gas cap would make a huge woosh, but that's gone! I believe that vacuum in the tank would prevent the fuel from being sucked by the pump and on occasion I would stall and wouldn't;t be able to start up unless I released the vacuum in the tank. and the amount of vacuum pressure was HUGE.

I haven't done long term road tests because the car isn't road worthy yet, but so far my "driveway tests" seem positive.

Reid Fleming

iTrader: (2)

I've been running the Tanks rollover vent valve for a few months now. I've had nothing but success with it. My car has made the honking goose sound after it's been parked since brand new. Fuel pressure upon taking off the gas cap has always been a long hiss. The problem was much worse after moving to Texas (warmer weather all year round). Once the temps get into the 90's, the car would seemingly always lose power and vent while driving down the road. Getting worse and worse as time went on.

After putting in the valve, I don't notice the loss of power from the heat. I never hear the tank bubbling upon shutting the car off. And the fuel pump sound went from audible to silent.

One of the questions is will my car stink of gas? My answer is no. It's just the opposite. The worst gas smells came when I was either
a) driving the car with the windows down and that long whine would occur. Sending raw gas smell everywhere.
b) parking the car after said driving experience and that gas smell would be just bursting to get out.

Now? I don't notice anything getting out of the car. Which makes sense to me, as the pressure is essentially stagnant now. What happens when I take the gas cap off? There's still a bit of pressure. Though nothing like before. I would say the sound after the valve, is like opening a can of pop. A small "psst" and that's it. Opening the gas cap before would sound like I was disconnecting a compressed air line from the wall.

Overall, I'd recommend this valve. I like that it's not brittle like the stock one. There is no question of it working or not. And it's got to be good for protecting the fuel pump and the tank. No more embarrassing raw gas, high pitched, whines at stop lights either.

1989karr

looks like Hawks is making the vent valves now!!


. 82-92 Camaro Firebird V6 & V8 Fuel Tank Vent Valve, Reproduction - Hawks Third Generation (hawksmotorsports.com)

Vader

That's dedication.

Csani

[QUOTE=GeneralDisorder;6145781]But does this valve, that no one will ever see, destroy the essence of "what the car is"? If it solves a problem, and I would argue that the discontinued valve IS a problem, and allows the vehicle to still be enjoyed.....

Original parts for the sake of original parts is fine unless they are flawed in some fundamental way. Reliving the 1980's of discontinued plastic emissions equipment is like.... complete torture.

There's like a whole world of sunshine, hot babes, and cool cars to enjoy. Worrying about having the factory plastic emissions valve seems kinda silly doesn't it?

I'm a mechanic, machinist, shop owner..... as such I guess my perspective is just different. Original appearance is all well and good and I understand that. But original function is sometimes just not worth the trouble or no longer applicable to the car's modern life.

A few years later, in Europe. I had a problem with the EVAP system.There is no emission control here.It's only a problem if the car doesn't run.The new air valve was also bad.I drilled out the tank cap.The pressure wasted more gasoline....so more seals survive :kiég: