EDGE

LOL. Seriously, there has to be enough brain power with the amount of us on here that have had, and still have this issue to figure this out. At this point, it doesn't even make nonsense. What's really odd is that it's happening on bone stock cars as well, which leads me to believe that aside from ethanol, the base fuel itself has had something added or taken away. I presume it's altered the boiling point. I did add the two heat shields yesterday, and had a muffler temp of 170 degrees Celsius, and a tank temp of 45 Celsius. As per the manual, the Evap can is supposed to hold tank fumes until the car is running, when under throttle it will vent to the engine. So, if the car is off and the tank is warm, it stands to reason there should be a pressure release when the cap is opened. Not enough that it achieves sub-orbital flight, as I've experienced when it blasts off when I open it, and the filler neck sounds like a freight train rolling through town. That was when the vacuum line under the manifold was burned through. The very one that controls the purge valve.

TecknoMike

I feel I have gathered enough running time to post an update for my car. I last posted in this thread back in 2012 with much of the same problems as everyone here.
Shortly after posting back in 2012 I replaced my (Walker?) brand fuel pump with an ACDelco EP241 fuel pump. I also replaced the big fuel tank O ring with a ACDelco G10. Right off the bat this delco seal is a much better design, with three little "tabs" on the ring to hold itself firmly in place on the tank while you close up the sending unit, instead of flexing and deforming as you try to lock up the tank.

With that said all of my fuel problems are completely gone. I have gone further distances than I originally did for the last 3 years in this San Antonio heat with 0 problems. This fuel pump is also very quiet, I only hear it when the gas is near empty, and even then it isn't that bad. My car has remained completely stock the entire time: 100% stock exhaust, stock heat shield, etc.
I also noticed that there never seemed to be a "buildup" of fuel tank pressure anymore either. Before the pump change there always was that usual loud and long hissing whenever I took the cap off to refuel. But with this pump, there was nothing.

With that said, I'm very confident that the fuel pump was my issue. The improved fuel tank seal also removed any doubts that the O-ring "moved around" while I closed it up, so I know for sure my tank is sealed up properly. Spending these last 3 years in the same hot weather with no other modifications to the car says to me that pump and/or tank seal was the problem. If you guys already have a good pump already, I highly recommend at the very least you consider checking out your sending unit seal. The typical flat ring seals always gave me issues when installing. It would always slide around or bend a bit.

IMissMy86TA

good info.. still not ready to change the pump. I have pressure as a new one would but a bit more... I have never changed the fuel filter and I want to check the vent tube filter as well. that is this weekend and we will see how things go. I will switch gas to be on the safe side....actually I cant find any locally.. they all are marina that sell true gas in my area

TTOP350

iTrader: (8)

In all seriousness, how much fuel is in the tank when this happens in the turn?

EDGE

It can be near full, to near empty. I know what you're getting at. I've stalled it when hard cornering before at low tank levels, but it starts right up. What I'm referring to here is, just sitting still in the intersection when it shuts off. Then I get out, and looking like an idiot I push the car through the turn, then try and figure out what animal figures the clouds are making while I sit and wait for the fuel to stop bubbling.

Bob88GTA

iTrader: (2)

LOVE IT! That's never happened to me.

Elthesh

I'm not sure if this will provide anything useful, but I had a somewhat similar problem. The only time the car would stall though is around sharp corners. This was AFTER I had a chevy dealer replace the fuel pump. They gave me all kinds of runaround and lies about why the car smelled like a leaking fuel tanker and why there was this train whistle coming from the rear end.

Finally, I had had enough and did the following. I wanted the entire fuel system at the tank replaced. I bought a new tank, new pump and float and cap. I took the car to a shop and told them to replace it all. The mechanic apparently commented that there was no way there was anything wrong with the tank and had no idea why I was replacing it... That was until he dropped the tank and saw a large hole in the very top made by a screwdriver or something of similar size. You could see where fuel had escaped through the hole and washed down the area around the hole. Even with the hole in the tank, it still hissed when opening the cap. No idea how that was possible, but...

Anyway, just tossing that out there. All my problems with the car stalling and such were caused by a hole in the top of the tank. I know everyone doesn't have that problem obviously, but it can at least let you know that a hole caused the stalling around corners for me somehow.

These things also have a tank vent valve that looks a bit like a mushroom and was whitish near the drivers side rear wheel, way up high. I replaced mine with a brand new one a few years before this incident.

IMissMy86TA

any part number for that part?
I would like to replace mine along with fuel filter

Bob88GTA

iTrader: (2)

GM Part# 10029752
Superceeded Part# 10033125

Elthesh

Yep, that would be the part number. You can see a great photo of it using the 2nd number in a google search. Also a great photo of where it attaches a few photos away from that one.

Bob88GTA

iTrader: (2)

You just can't find one though

Elthesh

Unless you hit up a junkyard or get lucky, it isn't easy to find. 2 new ones sold last month on ebay, but... This is where you may need to get creative and see if the 4th gen valve works. It looks similar and plugs into about the same place from what I can see, and I don't see why it wouldn't, but I really don't know. Here's the 4th gen valve number

10245442

IMissMy86TA

thanks. fuel filters are normally stocked though?

Elthesh

Yeah, fuel filters are a dime a dozen. Try to get a good quality brand name one.

EDGE

Fuel filters are an easy find. However, that won't fix this issue. It should be changed especially given its age. You'll likely gain a bit more fuel flow, I did. But this heating problem is a different thing altogether.

Bob88GTA

iTrader: (2)

ACDELCO Part # GF652F
FRAM Part # G3727
BOSCH Part # 71064

EDGE

I had the car out today for a 50 Kilometer drive, both city and highway. This was after I re-connected the vacuum line by the distributor. There was a noticeable difference in tank pressure. As in there was next to none, if you get to the gas cap immediately after shutting the car off. Wait too long and there will be a little bit, but not an explosive blast. That's how the system is supposed to operate. Those contained vapors will slowly make there way to the charcoal canister and burn off when the engine is started next and the car is under way. Guys, check those black nylon vacuum lines under the plenum. Check all of them. The one that controls the purge solenoid for the Evap is tee'd into, and comes off a 90 right underneath the Throttle body. That lines main vacuum source is from the connection by the distributor, nestled down between it and the coil. Check them for a burn hole in that run. Any one of those lines could have failed, and that purge solenoid will not work. (I cannot stress enough how important it is the make sure that tank is venting. See below in Red) I don't know if I've solved my problem, but there's a big difference between today and the other day when the car stalled. Beyond that, the bigger problem, and I'm 99.9% sure this is the primary cause of all our issues is Vapor Lock. I've seen a lot of posts here where people are under the impression that Vapor Lock can't happen in an EFI system. IT ABSOLUTELY CAN!!! It happens to a Carb car in the float bowl. It happens to our TPI cars in the fuel tank. Either way the result is the same. We have very old and dry vacuum lines. They could be cracked and/or burned. The car was designed with a muffler below the tank. It's worked for years. There's really not a lot that can go wrong back there. There is up front though. The hot tank in itself may just need the extra push over the edge, which would be a tank that can't vent. Now the heat becomes the major player. It causes the pump to Cavitate. When a pump Cavitates just once, it's permanently damaged. With each occurrence it gets worse and worse. So, I'm gong to be into another pump change soon. Below is an excerpt from Aeromotive:


"You may be experiencing EFI vapor lock. Even though the fuel is recycling through the car, eliminating localized hot spots, the recycled fuel is still being exposed to under-hood engine heat. Fuel in an EFI bypass system does slowly warm up as it is recycled through the chassis, the fuel rail(s), engine compartment, and finally back to the tank. The longer an EFI engine runs, the higher fuel tank temperatures can become. Unlike the more common carburetor vapor lock, where fuel is heated to boiling in the float bowl(s) or fuel line(s) under the hood, EFI vapor lock is often caused by hot fuel in the tank.

Excessive pump noise along with fluctuating or dropping fuel pressure often indicate that fuel temperature is high enough to cause hot fuel handling problems. A combination of high fuel temperature and low pressure can result in cavitation, where liquid fuel changes to vapor. In a return style EFI fuel system, the most likely place for these conditions to exist in the same place, at the same time, is at fuel pump inlet. Once cavitation starts, it will feed upon itself. As vapor enters the pump, it displaces liquid fuel required to lubricate the mechanism, allowing metal to touch metal, creating even more friction and heat. Once the pump begins to super heat, a complete vapor lock will develop.

In order to prevent cavitation and vapor lock, correct fuel system design and installation are vital. Ensure supply lines and inlet filters meet hi-flow, low restriction requirements and are kept clean. Keep the tank full on hot days. Reduce fuel pump speed and recycle rate with a fuel pump speed controller during low load, idle and cruise conditions. Carefully route fuel lines and plan component placement to avoid exhaust heat. Do not overlook proper tank ventilation, if the vent line or vent valve do not allow ample air to move freely in both directions, fuel delivery problems will never fully resolve. Any conditions that restrict the pump’s access to fuel in the tank must be addressed"

IMissMy86TA

Thanks guys

EDGE that is great info!

EDGE

*UPDATE*

I can say, in all confidence that after almost 15 years, I've solved this issue. At least for me. New Evap can. The can was somewhat plugged but the system tested fine, every time. I overfilled the tank too many times in the past. It wasn't filled with liquid but it did not shake like the new one. Odds are it was slowing down the venting, allowing for pressure to build up. I also found my Harmonic Balancer had slipped and my timing was way out. Since doing all that, and a major tune on the PROM, the engine is running much cooler. Less heat transfer to the fuel line. Car runs best it ever has now.

hellz_wings

iTrader: (2)

Wow I didn't know that evap can could get plugged?! I think I've seen replacement cans at some places online but never thought to change it.

EDGE

Nor did I. But if you fill up to the point the fuel comes up the filler neck, you could send fuel up the line to the Evap can. When I shook the new one it was lite and sounded like sand. The old one was noticeably heavier, and was not loose inside like the replacement. Fortunately I was able to source a brand new exact replacement.

Formula_C10

Well I'm going to toss my hat in the ring for this heating issue too. The odd thing here is that its not happening in a third gen car.
I recently finished a TPI swap from a 1990 Formula Firebird into a 1967 Chevy C10 pickup. If its hot outside, I can almost bet I'm going to have fuel cuts after driving it for a while. The only commonality is the all stock TPI motor (does have headers though...). I'm using the stock tank to the truck that sits behind the seat in the cab, an inline MSD fuel pump mounted to the passenger side frame rail, and a return line that runs down the driver side frame rail. Its as basic a setup as you can get... no Evap can, etc. The fuel pump wines really quiet when its having the issue... just like some of you with the in tank pumps.
So all the little tricks that everyone is suggesting, wont work in my situation because its not applicable to my situation.
Its the 305 TPI motor, stand alone harness, fuel pump wired through the ecm like stock.
Just thought I'd add some food for thought here...

Steve Mack

iTrader: (5)

Do you have a vented gas cap?Your best bet is to get a fuel injection tank and move it to the back of the truck.No gas fumes when you roll down the window or fill the gas tank.

Formula_C10

Eventually I will relocate the tank to the rear of the truck, out of the heat from the exhaust and cab, etc. I just wanted to get the motor in and running. Its only been on the road for about 3 weeks now. The gas cap said "VACUUM PRESSURE" on it, so I'm guessing it wasnt vented. I snagged a vented cap last night... going to see if it does anything.

cptwolves

Does anyone know what that is, and what it should be plugged into

L98GTA87

iTrader: (1)

That's your fuel tank vent valve. Doesn't plug into anything but it's missing half of it.

Camshaft3

I have a 305 tip out of a 1988 iron in a streetrod. Everything was fine last year and drove in local Christmas parade on warm day with no problems. Car sat about 2 months before next drive and after a couple of miles I started having a hesitation when starting off from a stop, mind of like vapor lock, peddled it a little and it went on. Runs great going at highway speeds but when u stop at a long light the external fuel pump starts to whine and if the light is long enough it will start running rough and cut off. Let it sit 30 mins and starts back and runs fine. Checked all my fuel lines and all clear. Have a as braided lines. Car has run great for 4 years and now just won't go from a stoplight. Seems to be getting worse. Does anyone have any suggestion what to check? Have read all the notes about this but my situation is different with a external pump. Thanks is, jay

dyeager535

Check fuel pressure.

No way temp of the fuel in the tank is enough to cause issues for the fuel pump, checking pressure is easy and free if you can borrow a tester from a chain auto parts store.

May have to try and replicate the issue with the tester hooked up since it's not a 100% consistent problem.

When the TPI setup was installed, were all fuel lines ethanol rated? Is the gas good? Have you checked for water in the fuel? These are fairly unlikely (except ethanol eating rubber not rated for it) but again, pretty well free to do, and can be a real issue with a vehicle that sits.

I get 4-6 months out of ethanol depending on conditions before I start to see issues with poor running with my vehicle that sits. I actually try to put it away with a 1/4 tank or so because I'd rather have to fill it up right away, than deal with trying to run through a full tank of bad gas.

jmckelvey

Hi Everyone! I need some help… This is my first post, so hopefully it's done correctly as a new post! I have read about everythread posted on this issue, but can’t find the solution… A few years ago, I boughta stock 1991 Camaro, Z-28, 5.7, Tuned port Injection, automatic. The car did not run and had been sitting solong the fuel had turned to tar. We scraped,vated, cleaned and treated the fuel tank; blew out all lines, changed the fuelpump (AutoZone), sock, and filter. The carseemed to run pretty decent. Summer of that year, the fuel pump stated whiningand eventually the engine would vapor lock and the engine would stall and notstart again for several minutes. Wereplaced the pump with one from Napa. Idrove the car back and forth to work (25 highway miles) almost every day. That fall I drove it from NM to MS which tookabout three days. A few weeks laterafter driving in stop and go traffic in M.S., I was on an elevated cure atabout 40mph. The car started stumblingand the engine stalled and vented a lot of fuel onto the ground. It was a busy street and in about 15 minutes,I was able to get it started and off the busy road. A local garage performed the repair andstated the fuel pump was bad, low pressure. I asked them to double check thelines and installation based on the above. I drove it home to NM later that fall.
About twoyears ago, my son changed schools adding 30 minutes to the commute. Every time it is hot outside, and I picked him up, the fuel pump would startto whine and a eventually vapor lock and die. Opening the fuel cap to vent the pressure would allow it to re-start andit was good for 15-20 minutes. When thefuel pump whines, we normally smell raw gas both inside and outside thecar. To this date, we havechanged/replaced the following:
1. Fuel pump (Autozone, 2 from Napa)
2. Fuel filter, 4+ times
3. Fuel pressure regulator (AutoZone)
4. Fuel tank pressurevalve (used)
5. Fuel tank vent (Used)
6. Vapor canister (used)
7. Fuel injectors (new aftermarket, stock spec)
8. Ignition system (other performance issue)
9. All fuel system O-Rings

Fuel pressures have alwaysbeen 50~60 psi at the rail. We have leftthe gauge on while driving but was not able to see the pressure at the exacttime of failure. We are convinced thisis a heating problem induced by ambient temperatures combined with engineheat. Fuel vapor temperatures have beenrecorded at 115 degrees + using a meat thermometer inside the filler tube. Withthat in mind, we stuck an engine bay heat blanket between the heat shield andtank; insulated the metal fuel lines from the rubber line to the fuel railinside the engine bay, insulated the alternator bracket where it bolts to theexhaust manifold, re-routed the water hose, and replaced the stock muffler witha much smaller glass pack. The problem getsbetter all the time, but still there.

A few weeks ago, wereplaced the tank, fuel pump (from Chevy dealership), and filter. The thought being the fuel tank treatment had failedas there was a lot of rust/debris in the last fuel filter. The measured pressureat the rail was 40psi, lower than all other previous pumps. Also, this pump has always been a lot louderthan any previous pumps. Twice now onthe way to/from my son’s school and temperature about 70 degrees out, the pumphas screamed (about the same as previous pumps), the engine stumbled but didnot actually die. Once he shut off theengine and relieved the pressure at the cap, and then took the cap off which causedabout a quart of fuel to spray out of the filler neck. He didnot feel like the fuel was hot, just too much pressure.

None of the fuel pumps installed had the pulser. About the only thing leftin the system are the lines themselves. Perhaps they are plugged. I havevent lines on hand and ordered a replacement pressure line. Is there anything else that could cause thisongoing issue? What was done to fix allthe previous threat issues? Any helpwould be greatly appreciated!

ULTM8Z

On mine, I removed that little vacuum operated valve that goes between the EVAP solenoid and the fuel tank on the main vent line from the tank, and have the main vent line connect directly to the EVAP solenoid.

I never get any pressure build up in the tank no matter how hot it gets. The car actually runs noticeably better with it off too.

I believe that valve won't open until a certain amount of pressure builds up to open it. Which was always puzzling to me since the ECM controls the tank venting through control of the EVAP solenoid.

jimdutro

iTrader: (1)

I stumbled across a "fix" that worked for 90% of the problems I was having. My `88 Iroc was having most of the symptoms as everyone else for the past 4 years. I`m on my 3rd ACdelco fuel pump in 8 years so I assumed it was a bad pump again. While checking the vapor canister, an NOS part I replaced 2 years ago, I noticed there was a slight gap between the purge solenoid and where it mounts on the canister. I sprayed electrical contact/connector cleaner around that gap several times and so far no more stumble, no fuel pump whine when it`s above 80 degrees outside,no more gas smell, I don`t have to keep my gas tank full either, I`ve run it down to 1/4 tank and no problems. I still get a slight fuel pump whine after the car has run for over an hour even at night but so far that`s the only issue, it does not effect the way it runs. I`ll try a Bosch pump next time I replace it, no more ACdelco for me.

jimdutro

iTrader: (1)

Update, I`ve been driving a lot in hot weather and still no issues. I had planned on replacing my fuel pump again and now I don`t see the need. I`m not even getting the slight pump whine after running for 1 1/2 hrs+. Beats me but my issues seem to be fixed for now.

jmckelvey

Thanks for all the replies. Unfortunately, we are still having the same problems this year. We did remove the evap canister valve, but did not help. The difference being is the fuel is now at a much lower temperature inside the tank but the pressure is way up from before. The last time it acted up the outside air temperature was about 70 degrees or less, cold for here. Anyway, we came up to a red light, the pump started screaming and engine sputtered. We got it out of the intersection and removed the cap. Pressure vented for well over a minute. This happens weekly and it's no longer safe to drive. I ran across a decent post today and will try and isolate issues with evap system.


We pulled the motor last week for a refresh/balancing. Seriously considering switching the TPI out for a carb. Unfortunately, did not have the additional $ 1000 for all new carb parts. We decided to give the TPI one last shot.


Since the car sat for so long, we thought maybe one of the 3 fuel lines were plugged, had holes or other issues. The motor has been out since Sunday. My son jacked it up from the rear end to take pictures. While up in the air for just a few minutes, it dumped about 3-4 gallons of fuel on the ground under the engine bay. He was not sure if the fuel came from the pump or return. He put speedy dry down and lowered the car and fuel stopped running. We decided to do a quick flow test before removing the lines for inspection. For the pump to pump out 1 gallon of fuel into a jug, it took 1 minute and 4 seconds. We took the gas cap off, jacked the car back up, and in a minute or so, had another gallon or so of fuel on he ground. Nothing from the pump line, just the return. We disconnected the return hose at the tank and drained at least 4 gallons out via gravity. There was only 6-8 gallons in the tank to start with....


My assumption is somehow we have created a vacuum causing the return line to feed fuel. Why was there a vacuum after sitting for 3 days and the cap was off or loose most of the time.


Is it possible the lines are connected wrong at the tank? It's been down at least 4 times in the last few years... We do know fuel pushed by the pump is flowing through the 3/8" supply line as verified with the flow test. We have verified several times in the past year that there is also raw liquid fuel in the vapor canister line from the tank.


Any ideas?

jimdutro

iTrader: (1)

Ok, I`ve been looking for an old post that tells which fuel line is which. Type "fuel line/fuel pump help," last post 1/11/14 and moderator RBob describes which fuel line is which. Good luck

jmckelvey

Thanks. Based on my understanding of the post my setup is correct. I added some pictures from the original fuel sender, hopefully they are not cut off too much... Anyway seems to me, this setup is poorly engineered. Why would you take hot fuel from the engine bay and dump it at the inlet to your fuel pump? When the pump and strainer are installed, the return line is sitting right on top of the inlet strainer...


If I have to pull the tank for a 5th time, I think I will add a hose to the return and get it away from the inlet... I think I will also remove the pump and mount an external...


More to come, I am sure...

jmckelvey

[QUOTE=jmckelvey;6023616]Thanks. Based on my understanding of the post my setup is correct. I added some pictures from the original fuel sender, hopefully they are not cut off too much... Anyway seems to me, this setup is poorly engineered. Why would you take hot fuel from the engine bay and dump it at the inlet to your fuel pump? When the pump and strainer are installed, the return line is sitting right on top of the inlet strainer...


If I have to pull the tank for a 5th time, I think I will add a hose to the return and get it away from the inlet... I think I will also remove the pump and mount an external...


More to come, I am sure..

jmckelvey

update: So I am in the middle of replacing all three fuel lines and need HELP. Trying to verify if I in fact have the correct return line selected at the tank. It is a 5/16" line and the other one is only 1/4" . If I blow into the tank via the 5/16" line, fuel is pushed out the 3/8" supply line. As soon as I quit blowing, the same amount of air is pushed back out the return 5/16" line.

Does that make sense to anyone? Am I making a mountain out of a mole hill? If fuel is reacting the same way, I can understand how the tank is being over pressurized. All other lines are disconnected except the white breather... I am pulling the breather now to ensure it's not plugged...

87gtaredonred

Im not following what your saying about the gap and the connector?? Is there any way you could take a pic for me. What exactly did you spray with contact cleaner the connector??

jimdutro

iTrader: (1)

I have a 2-year old nos ACdelco vapor canister and there is a gap where the purge solenoid attaches to the canister, it can be seen on top of the canister and feels a little loose. I don`t know how it is attached so I did`nt want to try and pry it out and break it, I just got lucky. That gap is where I sprayed electrical contact/connection cleaner, I spray a hefty shot around that gap every month and so far no more issues with my fuel system. I also replaced the vacuum tubing that attaches to the canister. If you don`t have an ACdelco unit it may not have that gap. I can`t explain why it worked but I assume the solenoid was stuck closed. I don`t have any way to take any pics for you, I`m still old school with the modern gadgets.

hilltop530

So, I've been having this same issue. I'm in process of doing an entire new system. Fuel Pump, Fuel Filter, New Tank pressure vent, both pods that go into the vapor canister, New canister/and, filter, new fuel vapor release solenoid. If that fixes it, I'll be sure to post my findings.

EDGE

I'm on my second summer now since I replaced the evap can and repaired the nylon tubing that controls it. Knock on wood but I've had no issues. Again, I was chasing this nonsense for 15 years. This is a venting problem exasperated but heat. I've posted all I've done about this bloody problem. You can fiddle fart around with solenoids and tubes till your hearts content, but if that little black nylon control tube under the plenum is burnt and welded shut, it's game over. The tank won't vent. I've gone on big 400 kilometer drives with the A/C on, sat in brutal 90 degree traffic and I'm seeing little to no pressure in my tank. This tank used to launch gas caps across the parking lot.

hilltop530

Yeah, I found my issue. I replaced all the lines that looked old from the tank to the can, up to the plenum. Didn't solve it. Replaced the Canister solenoid, element (filter) , and, valves, tank pressure valve and, nothing. Fuel pump, fuel filter, fuel pump relay, still nothing. Finally I replaced the ECM. Problem solved. The ECM controls the Purge solenoid and, it just wasn't. New one works like a champ. Ran the car 5 days in a row now in 100+ degree weather. Tank is holding pressure but, not an extreme amount. (vapor cool to the touch out of the filler cap). The issue for me was it was intermittent. Couldn't hunt it down very easily with testing volts because it would work, not work, and so on.

EDGE

Good find. Either way it always seems to be a pressure/vent issue. The way it's controlled seems to be where the issues are. And there is more than one control path. Glad yours is solved. It's a real pain in the a$$. Takes the fun out of the car.

hilltop530

Yeah, there is a ton of stuff that could cause it. Not a lot of replacement parts out there either unfortunately. So, it's cleaning and replacing lines and, pods. I used a canister purge solenoid from a 95 because there wasn't a replacement for mine. (works great. same 2 wire ecm controlled part).

jimdutro

iTrader: (1)

Good to see your issues are solved. I`ve had no problems driving in 95+ heat this summer, that is a first for me.

87gtaredonred

I believe I finally pretty much fixed mine, I changed lines and checked and rechecked and changed solenoids. As far as I could tell it was venting properly just the gas that was returning to the tank was getting hot as hell the longer it run. I rerouted my return line. I put a regulator just after my filter and run the return to the tank. Ive driven 4 and 5 hrs straight in 100 degree heat now only issues I have is if ive been driving several hours in heat and the tank is getting low yea there will be some pressure but nothing like before like others say almost like the car was going to explode lol. There might be alittle pressure on a hot day with the tank empty but as soon as I feel it up its back to normal

jmckelvey

87gtaredonred: Do you have any info on the regulator you installed? I had thought we had our heat/pressure issue resolved by cleaning the white breather/valve that is next to the rearend. The breather/valve was very sticky and full of gunk. The Camaro is now driveable! Now we have to be careful when fueling as it tends to shove fuel out the gas filler tube.

87gtaredonred

Mine spits out also, i punched 2 holes at the filler hole it helped alittle. I also found it has alot to do with the gas pumps themselves, some of these newer pumps just flow so fast it cant keep up if im making sense. I used an areomotive adjustable regulator and a few an6 fittings and adaptors. Just screwed in the regulator just after the filter and the return line out of the regulator I ran a rubber fuel line out of it to the return line of the sending unit and capped off return at the fuel rail. Set my fuel pressure and drove it silly. I have a pic somewhere ill see if i can find it

87gtaredonred

Hope this helps<br/>

Johnny*G

Hello TGO, I have the fuel tank boiling/over-pressurizing issues as well. Was more noticeable after the flowmaster 80 series muffler install. Stock shields in place and the muffler has the proper clearance from the shield. Called Flowmaster, they do not sell the additional shield(s) anymore and the guy at the counter got a lesson from me on the issue. he said if it was a common problem they would get 10 calls a day. I said i'm surprised they don't, LOL. I would like the additional shielding. Maybe ebay...