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I've been trying to resolve a gremlin with my car and I'm starting to think the issue started after I replaced my fuel pump. My fuel pump went out in 2006 at 13,500 miles. In 2011, I went on the Hot Rod Power Tour and had fuel "heat" issues really bad. The car had 15,500 miles at that point. So, putting 2000 miles in 5 years makes the issue easy to miss!
In some of my research, I'm finding that most of the people experiencing boiling fuel, high fuel tank pressure, gas caps not able to close completely, heavy gas smell, etc, all came after the factory fuel pump was replaced. In my case, the charcoal canister can't be bad at such low miles. It's just a filter! I disconnected my tank vent line today to see if the canister, solenoid, purge valve, etc could be the problem. so far, results are inconclusive. I need a longer drive. However, my tank still got hot and I could hear the gas boiling after a drive today.
Can an owner of a factory original car, that does not have these issues, tell me if the gas tank itself is hot after you drive on a warm day? I'm pretty sure the gas cap not sealing correctly when the car is warm is due to the tank getting so hot, the filler neck expands and then the cap won't fit properly. The heavy gas smell is probably also related to the heat causing the gas to vapor more than normal. I think all of the issues I'm having are related to one issue, hot gas. My question is if the new fuel pump runs hotter than the factory. If so, I need to find out why.
saw this... I posted on your other thread but will do here as well..sorry for the dupe: I dont have an answer to your issue but I am a original fuel pump owner I am sure as I got the car with 19,900 miles (now at 22K)
Scott I am having similar issues except I have major pressure in the tank and hot gas. If I open the gas cap I get a lot of pressure and can feel the heat. if I don't release the cap after a drive and it sits in the garage I will hear a high pitch whine... from the cap I think or the vent valve?The car has a hard time staying at idle due to this and will die at lights. If you open the cap and drive it will drive for a while then have issues after a while. I am concerned since I have a long drive (80 miles) in aug with my son to a car show and the last thing i need is an explosion due to hot gas if I dont stop it will run but again boiling like you have. it looks like to change the pump it a bear of a job... https://www.thirdgen.org/forums/hist...placement.html (Which fuel pump is a drop in replacement?)
I do find if I put in some lucas fuel system cleaner it does well for about half a tank then starts having issues again... it seems like a short term fix
I have just got my car back on the road this spring 2015 after working on the whole gas tank system. gas tank out new everything almost all AC parts. I have never had this issue and have drove for hours at speed all day in the past. I hope I do not get this problem also. but one thing I did find was the vent hose for the tank connects to a valve sorry I cant remember what we call it but what I did was soak it in dish soap for days an cleaned it out real good. I may have used some harsher cleaner on it too.
what I noticed was it would not burp before I cleaned it real easy. much easier after all the soaking an cleaning. fuel under a vacuum will boil at a lower temp I believe. so maybe related.
most of my reason for working on it was fuel pressure related. I am going to follow this an see if I can confirm what temps my fuel tank runs at. Dan
"also... would you consider doing this if the pump does need replaced? (http://www.mifbody.com/vbulletin/sho...res-and-How-To)"
I can't believe you just asked Scott this...
I believe I will have to drop the tank etc.. I have heard about people having to change back out a faulty pump after the replacement. I am not a mechanic and the idea appeals to me. it is something no one would look for and no one would see. If done carefully and right looks like much less work and easier to fix in the future. I think of my house and my sump pump I have had to change a couple times. a quick connect is not stock to the house but since it is something that fails regularly the quick connect comes in very very handy. and can be done well...(https://www.thirdgen.org/forums/atta...5-14.51.42.jpg)
A boiling tank scares me a lot
Last edited by IMissMy86TA; 06-01-2015 at 10:14 AM.
I am following this and Scott's other thread on the subject with interest. Other than my '85, AFAIK, my other 3rd gens have the original fuel pump. My '89 I can tell you 100%, since I'm the original owner.
Other than my '85, none of my other cars have exhibited the mentioned symptoms. The fuel pump was replaced by a previous owner on the '85. I have no idea who the manufacturer is. Whenever that car gets below 1/2-1/4 tank, the fuel pump begins to whine. A couple of times on very hot days, I've gotten similar symptoms as Scott's car.
Just an aside. I read somewhere that Chevron Techron could help with noisy fuel pumps. On my '85, I was down to around a 1/4 tank on a warm day and the fuel pump was doing it's usual screeching. I put in a bottle of Techron, and literally within a minute or two, the pump became completely quiet.
No, I will not put the trap door in any car I own. If I'm in the market for another third gen, that will be something I look for. That's structural damage in my mind. Any low mile car for top dollar will lose 50% value if I see a trap door. I understand the theory if the parts need to be regularly swapped, but once every 25-30 years doesn't warrant destroying the car.
lt500r55, the purge valve that you soaked was replaced on my car. It's a cheap replacement, so I just ordered a new one.
Like I said I don't think I will do a door.. but the idea appeals to me.
the odd thing is when I release the cap and the air goes out ...after that I have no whine.... just pressure and heat. I am thinking mine may be due to at least partially to the pressure vent your replaced.
I had to replace my original pump because of the hot fuel issue. Being stationed in Florida my car basically cooked the fuel pump. After replacing the pump I noticed the same symtoms as before. After a lot of reading through the forums about others experiences this is what I tried and it seems to have cured my boiling fuel issues. I purchased a FPR with the appropriate adapters and installed the FPR imediately after the fuel filter. I disconnected the return line above the axle and ran a piece of 5/16 fuel line from the return of the FPR to the steel return line going to the tank. I disconnected the return line from the fuel rail and capped off the the fuel rail return. I no longer have hot fuel returning to the tank and cooking the fuel pump. As far as pressure in the tank, I only get this once in a while and its very little especially since I replaced all of the vacuum lines on the charcoal canister. I have been running the car like this now for almost two years with no issues.
No, I will not put the trap door in any car I own. If I'm in the market for another third gen, that will be something I look for. That's structural damage in my mind. Any low mile car for top dollar will lose 50% value if I see a trap door. I understand the theory if the parts need to be regularly swapped, but once every 25-30 years doesn't warrant destroying the car.
lt500r55, the purge valve that you soaked was replaced on my car. It's a cheap replacement, so I just ordered a new one.
Agreed!! I went to see a low mile TA a couple years back that had this done... to me, any low mile collector car is basically totaled in my eyes if someone does it...
As far as replacing the fuel pump, I've done it. The hardest part is getting the rear high enough to drop the axle and get the tank out of the 1/4 panel without bending the neck at all.
As far as replacing the fuel pump, I've done it. The hardest part is getting the rear high enough to drop the axle and get the tank out of the 1/4 panel without bending the neck at all.
so you did this and still having an issue. Makes me want to go other routes first before replacing the pump. I get hot fuel but the pump is not making noise. First I will replace the fuel filter then look at the overflow/release valve off the neck I saw you replace in your other thread maybe getting another OEM gas cap (the current one has a very quiet whistle under the pressure but I think it should just let out pressure if its extreme or maybe I don't get how it should work). Keeping fingers crossed. very interested in what you find is your issue scott
I replaced my fuel pump because the factory one died. Left me stranded on the side of the road! I don't recall ever having this issue with the factory pump, that's why I'm wondering if it could be the replacement pumps run hotter than the factory pumps.
I'm half tempted to buy a new pump and install it in a test tank, apply 12 volts and let it run for 20 minutes to see if the tank is hot. Having 12 gallons of fuel pumped from underground it should have been cold, but after 20 minutes of driving, my tank was hot, even with the vent open. As Drew said, having the vent open completely eliminates the charcoal canister, purge valve and solenoid. It could be the pump or the vent tube is clogged.
I had an all original car for a while that was the original pump, it would build up pressure in the tank, but I never noticed if it was hot at all. After a few years it developed some fuel related driveabilty issues and I replaced the pump trying to fix it (AC Delco pump). I also blew out the vent line and made sure it was open. I don't know if it was the pump or the vent, but the pressure issue seemed to be gone after that.
And I had always assumed GM designed the filler neck to bend slightly for tank installation. It's easy to bend back once the tank is mounted.
And I had always assumed GM designed the filler neck to bend slightly for tank installation. It's easy to bend back once the tank is mounted.
How can you design the filler neck to be bent and restored without installing something flexible in the neck? Usually people bend the neck a little and find that they broke the weld where the filler neck meets the tank.
If you raise the rear end high enough to lower the rear axle down as low as possible, the tank will come right out with a rotation of the tank. The reason most people have issues with this is because we don't have a lift to get the car high enough to lower the rear axle. A shop will have no issues swapping the tank. GM didn't design the tank replacement for the home mechanic, but it can be done.
How can you design the filler neck to be bent and restored without installing something flexible in the neck? Usually people bend the neck a little and find that they broke the weld where the filler neck meets the tank.
If you raise the rear end high enough to lower the rear axle down as low as possible, the tank will come right out with a rotation of the tank. The reason most people have issues with this is because we don't have a lift to get the car high enough to lower the rear axle. A shop will have no issues swapping the tank. GM didn't design the tank replacement for the home mechanic, but it can be done.
You don't need a lift. A good set of jackstands will get it high enough. I have done several and the first was a learning experience but the second was a breeze. And like you said - a little twisting will get it out without bending the filler neck.
I might not have been clear in my description above that it can be done if you get the rear high enough. Most people don't realize just how high you need to get the rear and they don't usually go high enough which causes them issues getting the tank out. Jack the rear as high as you can go and you'll be fine, without damaging the filler neck, the rear quarter or the tank itself!
The last tank I pulled, the exhaust was already out of the way, and I was salvaging the rear. After rolling the rear, torque arm and all out from under the car, the tank came out incredibly easy. The only painful part of changing the pump by the book is when the control arm and track bar bolts are rusted solid and won't come out, or if the exhaust can't be removed. A trap door sounds great, until you realize that in a thirdgen the hardlines off the sending unit go all the way down and across the tank almost to the frame rail where the fuel lines are mounted. There's no way you're getting the sending unit out without hacking all the hardlines. In the end, doing it right doesn't take any longer.
i had this problem last year on my 89 iroc vert... the original fuel pump was going bad and would die after running ~15 minutes.
with the fuel at 1/4 tank or so i could actually hear the fuel boiling in the tank when i was working on it in my garage trying to initially figure out what was going on.
long story short, i did drop the tank, replace the pump with a good walbaro, replaced the entire sender assembly (ditched the pulsator) and also cleaned the "ufo" disk
that was mid summer last year, no problems since and it has driven great
How can you design the filler neck to be bent and restored without installing something flexible in the neck? Usually people bend the neck a little and find that they broke the weld where the filler neck meets the tank.
If you raise the rear end high enough to lower the rear axle down as low as possible, the tank will come right out with a rotation of the tank. The reason most people have issues with this is because we don't have a lift to get the car high enough to lower the rear axle. A shop will have no issues swapping the tank. GM didn't design the tank replacement for the home mechanic, but it can be done.
I'm not a home mechanic (well, that's a lie, I have been for a couple years now... but anyway) and every fuel pump I've put in a 3rd gen has been with the convenience of a lift. And I've done my fair share of them. The filler neck has ALWAYS got hung up where it passes through the body, on the pinch welds. For me at least, no matter which way I position the tank. I've found it best to first remove the filler housing and tweak the neck down just slightly. A length of solid bar stock inserted into the neck works fine, then carry on lifting the car and removing everything else. When done and the car is back on the ground, simply insert the bar and put the neck back where it goes.
It's not like the goal is to reshape the filler, just move it a smidge. It doesn't take hardly any force at all. Never had any troubles with cracks, broken welds, or leaks of any kind.
Uh, not sure I understand. You need to remove the filler housing to get the filler neck out of the quarter panel. Unless I'm misunderstanding what you're referring to, that's part of the correct removal process.
Uh, not sure I understand. You need to remove the filler housing to get the filler neck out of the quarter panel. Unless I'm misunderstanding what you're referring to, that's part of the correct removal process.
I'm just saying that was the very first thing I always did, remove the filler housing. With it out of the way, you can then tweak the filler neck down a little before the car is lifted and anything else done. Then the tank fits out of the car without much fuss. Trying to do it once the tank is unbolted and flopping around really doesn't work too well.
I believe mine still has an original fuel pump. My car won't have any of the boiling fuel or whining symptoms. However, if I go on a long drive or drive in the heat, pressure does build up in the tank and is released when pulling the fuel cap off at a gas station. The air coming out is warm, but not hot enough to cause any concern.
I plan to take the car for a good drive this weekend, so I'll check and see what kind of temps I'm looking at afterwards. I do have the "gas cap won't go on" when hot issue, but so far, no driveability issues. ...i have a friend who used to have an 85 Iroc, and he had all kinds of issues with bad pumps. Finally found out the actual lines were dirty, especially the return line. Cleaned/flushed em out and the problem went away. Can't say what exactly the problem was, but added pressure from clogged lines would certainly strain the pump.
I think the boiling fuel has more to do with weather than anything. Scott is in Florida and I'm in Texas, so we get similar heat and humidity outside. When I lived in Canada, it was rare to hear boiling fuel. But the weather was cooler and the traffic was nill. No chance of getting stuck in rush hour traffic in heat wave conditions. Every once in awhile I'd be out in the garage at night, polishing the car or with the garage door open and washing another car and I'd hear the GTA make a honking goose sound for a few seconds. This would happen about 45 minutes after the car had been parked. The tank was releasing whatever pressure had built up. That was in the early 2000's.
Fast forward to now. Parking the car (in TX), I'll get no rumbling fuel tank upon shut off during the winter months and more rumbling during summer months. On those crummy days where I get stuck in rush hour traffic coming home on a hot day, the tank will have quite a bit of bubbling going on.
The same applies in terms of opening the fuel cap to fill up. I get moderate hissing during mild weather and more hissing during hot weather. On those days where I'm stuck in traffic for an hour coming home on a hot day (let's say 90° or hotter outside), I'll get even more hissing going on when I open the gas cap. I've never heard about people not being able to put the gas cap on though. I know it takes about 7 turns of the cap before it makes that ratcheting sound to let you know it's on good. If it stops after 3 or 4 turns, then I know I didn't get the cap threaded on right. But even if there is something wrong with the pump or the relief valve, I don't see why the cap wouldn't go on. After all, if it's been off to refill the car, the pressure would have been released by the giant hissing sound.
I have read of people on TGO going 25-30 years on the original pump only to have their new pump die within 6 months. I chalk that up to cheap low quality fuel pumps. From what I've read the Walpro pumps aren't as good as the simple AC Delco replacement pumps. But then again, if that relief valve is gunked up with something, you'd always have more pressure in the system. And pressure = heat. The idea of soaking it in detergent to loosen up any crud sounds like a good idea to me.
I know I'm going to jinx myself but I've had several walbro 255 pumps and not a failure yet. the oldest was installed in the early to mid 90s or so.
They did have a some failure issues several yrs ago but I think they handled that very well. Took in a bunch of the failed pumps and studied them, found the failure issue and fixed it.
No, I will not put the trap door in any car I own. If I'm in the market for another third gen, that will be something I look for. That's structural damage in my mind. Any low mile car for top dollar will lose 50% value if I see a trap door. I understand the theory if the parts need to be regularly swapped, but once every 25-30 years doesn't warrant destroying the car.
I don't want to get too far off topic here, but I want to make something clear for others reading this thread. Scott, while YOU may think it's structural damage to cut a fuel pump access door, the reality is that it doesn't structurally damage the car, especially when done correctly. You're welcome to view it that way, you're welcome to scrutinize future purchases that way. I just want to clear up a fact for others reading your post.
That being said, no one defends using an air chisel or whatever was used in the picture above, and using rubber hose and clamps is another poor idea that I don't endorse. I usually rivet a replacement panel over the fuel pump area and seal it with 3M body seam sealer. I use brass compression fittings to re-join the hard lines after they have been cut. I've had one car done this way for 15 years and not had a problem.
You're right, it is my opinion and my choice, but I really can't see why you would need to do this modification. The original fuel pump lasted how many years? It's not like an air filter that gets replaced regularly. If you need to do the job once every 20 years, then why not do it correctly. In the amount of time you took to create the access hole, you could have dropped the rear axle and muffler and had the tank out!
The same applies to the power antenna. I've heard of people cutting the wires as they pass thru the side of the car into the fender. It takes just a few minutes longer to pull the stereo, release the antenna cable, then they can fish the power leads and antenna cable thru the fender opening instead of cutting. It takes less time to do it correctly than to resplice the wiring. Also, you won't have any potential failed splices or interference.
There are many ways to do the same task. I prefer the proper way or the way the manufacturer designed it to be done.
You're right, it is my opinion and my choice, but I really can't see why you would need to do this modification. The original fuel pump lasted how many years? It's not like an air filter that gets replaced regularly. If you need to do the job once every 20 years, then why not do it correctly. In the amount of time you took to create the access hole, you could have dropped the rear axle and muffler and had the tank out!
With a Metabo and an air saw I can have a fuel pump out in about 15min. There is no way anyone can get a tank out of one of these cars that fast. But that's not the point, it's not about being in a hurry, it's about being efficient and avoiding needless work and complication. When BIG MODS and I were on the Power Tour a few years ago and his fuel pump failed at the drag strip in St. Louis, we were able to replace the fuel pump start to finish in about 30-40min. And that's in a car with a Lexan back window that is not easily removable. TTOP350 was there, he saw us do it. Were it not for the access panel we would have had a very expensive tow and repair bill for no good reason. That's the largest reason I cut access panels when I need to replace a pump. Not to be in a hurry, but to ensure I'm self sufficient on the side of the road or on a long trip.
It's an agree to disagree situation, I 100% respect your opinion. I simply wanted to highlight that even though an access panel is frowned upon by most, it does not jeopardize the structural integrity of the car. That's the only point I'm trying to make.
Well - this is going to go way off topic if it turns into another fuel pump access door thread. But it does not make sense to do it on a car with low mileage and is in pristine condition. It's like cutting a hole in the Mona Lisa so you can access a light switch behind it. If its a well worn DD, and you think its a good idea, then have at it. I personally don't like the compression fittings. While yours may not have leaked, it is a potential area for leaking.
Bought my GTA with 19k and all stock, it does it less than my 91 Formula, which was definitely the worse of the two.
I will say to all those affected by this if the fuel tank vent valve is broken, you will know real quick when u take of the gas cap Also it is not a vent it is there to let fresh air in.
I've gone thru both, fuel pumps, cleaning the vapor lines, testing the charcoal canister/vent valves. Everything works as advertised and it still happens when it gets warm out.
Ironically, never experienced it on the TTA.
I would have to imagine doing a regulator near the tank like someone else posted would fix the issues to a large degree if everything else is working normally.
Spinning wrenches in a dealership for 10 years, you learn a few things. I do not believe fuel pressures were raised nearly across the board on everything unless there was a reason for it and I'm almost willing to bet it had to do with changing fuel blends(your not going to get wonder atomization out of injector going from 45 psi to 55psi)...... Check out any PWM fuel pump car. Check out the fuel pressure on a hot start. You can do the math on your own from there.
I'm not a home mechanic (well, that's a lie, I have been for a couple years now... but anyway) and every fuel pump I've put in a 3rd gen has been with the convenience of a lift. And I've done my fair share of them. The filler neck has ALWAYS got hung up where it passes through the body, on the pinch welds. For me at least, no matter which way I position the tank. I've found it best to first remove the filler housing and tweak the neck down just slightly. A length of solid bar stock inserted into the neck works fine, then carry on lifting the car and removing everything else. When done and the car is back on the ground, simply insert the bar and put the neck back where it goes.
It's not like the goal is to reshape the filler, just move it a smidge. It doesn't take hardly any force at all. Never had any troubles with cracks, broken welds, or leaks of any kind.
Bought my GTA with 19k and all stock, it does it less than my 91 Formula, which was definitely the worse of the two.
I will say to all those affected by this if the fuel tank vent valve is broken, you will know real quick when u take of the gas cap Also it is not a vent it is there to let fresh air in.
I've gone thru both, fuel pumps, cleaning the vapor lines, testing the charcoal canister/vent valves. Everything works as advertised and it still happens when it gets warm out.
Ironically, never experienced it on the TTA.
I would have to imagine doing a regulator near the tank like someone else posted would fix the issues to a large degree if everything else is working normally.
Spinning wrenches in a dealership for 10 years, you learn a few things. I do not believe fuel pressures were raised nearly across the board on everything unless there was a reason for it and I'm almost willing to bet it had to do with changing fuel blends(your not going to get wonder atomization out of injector going from 45 psi to 55psi)...... Check out any PWM fuel pump car. Check out the fuel pressure on a hot start. You can do the math on your own from there.
But what about the issue continuing with non-ethanol fuel? I try to run that as much as possible. Granted, I've been testing this in another thread where I recently filled up and I've been driving around, but I haven't done heavy traffic driving with the regular gas, so I'm not getting as warm. Maybe I should hit rush hour now and try it for awhile.
Well - this is going to go way off topic if it turns into another fuel pump access door thread. But it does not make sense to do it on a car with low mileage and is in pristine condition. It's like cutting a hole in the Mona Lisa so you can access a light switch behind it. If its a well worn DD, and you think its a good idea, then have at it. I personally don't like the compression fittings. While yours may not have leaked, it is a potential area for leaking.
But what about the issue continuing with non-ethanol fuel? I try to run that as much as possible. Granted, I've been testing this in another thread where I recently filled up and I've been driving around, but I haven't done heavy traffic driving with the regular gas, so I'm not getting as warm. Maybe I should hit rush hour now and try it for awhile.
I have found that a small bottle of fuel injection cleaner in each tankful I have 0 issue with the stalling. I do have pressure unlike yours though.
Fist I had a 85 I replace the original fuel pump with a sheep replacement from Auto Zone (BIG MISTAKE) it only lasted two weeks.
Then I replace that with a Hi Volume Pump I sold the car to my Dad and had no issues so far but he doesn't drive it at all.
Know for my 89 GTA had the same issue and decided to take some action to this. I haven't finish because Other things keep getting on the way but as soon as I finish I'll let you know if my mods did something or not.
First I think the heat is coming from the Muffler that sits under the tank. and as wee all know the heat tend to go up.
Second In my case the factory heat shield was missing probably by the person who change it previously so I'm getting one from other 89 GTA that I have for parts.
1. I'm protecting the tank with fiberglass since it is a heat shield.
2. I'm putting more fiber glass to the heat shield itself.
3. I'm putting some more Fiber glass to the top of the muffler.
4. I'm covering all fiber glass with Ceramic Paint.
I hope this will lower somewhat the heat inside the tank
To lift your car hi enough to drop the tank you need:
1. 4 6 Ton Stands (Not for the capacity for the height they have)
2. First take it up by the back as hi as it will go put the stands
3. then take it up from the front as hi as it will go and put the stands
4. finally take it up again from the back as hi as it will go and adjust the stands.
I've tried a similar approach, making an additional heat shield on my car between the tank and original heat shield above the muffler. I constructed it out of high temp fiberglass insulation and wrapped it in a radiant barrier then sealed it with aluminum tape. It did not work. Actually it made things worse, by reducing air flow around the tank and allowing it to retain heat longer. Which leads me to believe most of the heat the fuel picks up is from the engine compartment and pump.
05-30-2015 | 08:55 PM
Also it is not a vent it is there to let fresh air in.
thats how i did mine 
