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History / OriginalityGot a question about 1982-1992 Camaro or Firebird history? Have a question about original parts, options, RPO codes, when something was available, or how to document your car? Those questions, answers, and much more!
I got some excess Space Shuttle Thermal Heat Tiles I'll throw between the tank and muffler next time!
..........I wanna say the majority of the HEAT is coming from the return line from the engine. The engine/manifold/fuel rail is HOT.
Agreed! These TPI motors run hot and generate a ton of heat under the hood.
I have developed an alternate solution to try for mine. However those of you with low mile original cars would frown upon it.
With my AC compressor is taking a dump on me I decided to 86 the system since I never use it. I ordered the appropriate delete parts from Hawks.
A cooler fan switch from a grand national, 180 stat, and grounding the A/C system circuit. With condenser gone that will give me much better air flow to the radiator / motor, keep things much cooler and will allow me to turn on my fans manually with the A/C control panel while in traffic. The end result should do the trick. If it does not work, well I am out $200 and will have a clean engine bay and a cooler running motor.
Not ideal for some, but in my case while my car does look stock it is far from it. I do not mind doing modifications as long as they are done right in a neat and orderly fashion.
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.
Go chart what was in fuel 10-15 years ago and what is in it now and leave ethanol out of it.
Then do the same with what you learned above and overlap it with the ethanol as well.
Fuel is not what it used to be regardless of ethanol being added.
I would throw more up, but its been awhile since I dug it all up, but stuff has been banned, new stuff added, etc and so forth. MTBE was the biggie but not the only one.
Go chart what was in fuel 10-15 years ago and what is in it now and leave ethanol out of it.
Then do the same with what you learned above and overlap it with the ethanol as well.
Fuel is not what it used to be regardless of ethanol being added.
I would throw more up, but its been awhile since I dug it all up, but stuff has been banned, new stuff added, etc and so forth. MTBE was the biggie but not the only one.
I agree. it cant be just age of these cars due to many are in great shape (like scott's) and it pains me to agree we seem to be chasing ghosts. fuel system cleaner works for me with each tank and since its not a daily driver I can afford it. I think it may add some things that were no longer in gas or compensates some how but somehow fixes my gas issues.
I agree. it cant be just age of these cars due to many are in great shape (like scott's) and it pains me to agree we seem to be chasing ghosts. fuel system cleaner works for me with each tank and since its not a daily driver I can afford it. I think it may add some things that were no longer in gas or compensates some how but somehow fixes my gas issues.
Hope this helps?
Mike
As I said in my earlier post, a bottle of Techron worked literally within 2 minutes for me. So maybe you are right.
Just want to mention that my with my original pump, this did not happen. With the oem pump that the dealer replaced it with, I DID hear serious boiling from the gas tank. However, I tossed that pump due to other issues for a Bosch pump and have not noticed any boiling going on.
I made an effort to take the gas caps off all cars after running. It was right around 95 degrees outside this past weekend with the humidity level reaching "Swamp Azz" level's, or other words, REALLY HUMID!!
These are the results:
My 88 5.7 Hissed on Sunday, pressure in tank, drove 4 miles. New GM Fuel pump 10 YRS AGO, BUT, THIS CAR HAS DONE IT SINCE NEW...21 OF THOSE YEARS IN THE MOJAVE DESERT, California..Arid and HOT!
My 89 TTA 3.8 Hissed on Saturday after a "in garage warm up". Original Fuel Pump, 29k miles
And the 85 5.0 Hissed on Saturday after a "in garage warm up". Original Fuel Pump, 56k miles
2000 WS6 RamAir T/A Did NOT start it, but known to hiss (OFF TOPIC)
The 96 Bronco 5.6 hissed after warm-up in driveway, (OFF TOPIC)
Wife's 14 Ford Edge 3.7L just sits there....no gas cap, just a little flapper, no hiss (OFF TOPIC)
As mentioned earlier, my 14 TL 3.7L hissed this morning when I took the cap off and it was 80 degrees. (OFF TOPIC)
2005 Craftsman 26hp Garden Tractor, Carb"d no hiss, (OFF TOPIC) Had to throw that in.
I'm at a loss on the whole subject, and sorry for getting off topic.
The hiss is normal. What I'm questioning is the excessive hiss, gas blowback and extreme heat in the tank. It all appears to be related to not getting in fresh air or not venting properly.
Another thing to try temporarily, replace the plastic tank vent with an inline fuel filter. This will allow the tank to vent more easily. On my IROC my tank would pressurize so much the engine would start idling like crap and running too rich. Didn't notice it driving, but at idle the wideband O2 was pig rich which is not normal. I diagnosed it as vapor pressure going through the canister and purge solenoid. I could open the fuel cap and it would idle fine, then put the cap back on and after seconds it would go rich at idle again.
The hiss is normal. What I'm questioning is the excessive hiss, gas blowback and extreme heat in the tank. It all appears to be related to not getting in fresh air or not venting properly.
scott do you have the stalling out? Thats the issue that the cleaner fixes for me for that tank.
Good post on this subject from another board. Here is the gist : "problem with your canister vent line. The fuel that returns from the fuel rail is hot, when it gets to the tank it heats the other fuel causing pressure. This pressure is supposed to vent to the charcoal canister where it is absorbed by the charcoal then pulled from the charcoal into the intake to get burned." http://www.camaroz28.com/forums/3rd-...s-tank-144294/
According to these guys "Therefore you should not exceed the required fuel flow rate by more than 33%." (or too much hot fuel flows back to tank and robs octane) http://www.howrah.org/fuel-pump.html
So, has anybody that tears their car apart more than me ever tried to test the amount of pressure that these new fuel pumps are putting out in comparison to what the service manual states? I'm still wondering if the fuel pump could be the issue.
My neighbor has a 39k mile '89 IROC-Z. He said I could take the charcoal canister and the purge solenoid from his car and see if there is any difference in my car. I'm thinking there won't be, but it will give me the peace of mind that those components are still good. I'm also going to climb under the car this weekend and replace the fuel filter and see if I can blast air thru the vent line from the rear to the front. Is that possible without dropping the tank? I don't remember if there is a clamp connection back there that I can disconnect or not.
I have changed my evap canister, vent valve, all vacuum related components, the pump, fuel filter, checked all lines for blockages and I still have this issue on hot days. ????
This is interesting to know since my 91 Trans Am has a original pump in it and i live in florida where the humidity and heat is really up there and have never expierenced this issue before other than the occassional hiss when you take the cap off for gas. I've driven this car across the country from florida to tacoma washington and never had boiling issues.
This is interesting to know since my 91 Trans Am has a original pump in it and i live in florida where the humidity and heat is really up there and have never experienced this issue before other than the occasional hiss when you take the cap off for gas. I've driven this car across the country from florida to tacoma washington and never had boiling issues.
As a original owner of two third gens I can tell you for a fact they hissed when brand spanking new. this is because the whole system is designed to be pressurized. the issue scott has is no pressure and rough idle. mine is just a rough idle and stalling.
we have a lot of mechanical talent on these boards and very surprised that so many of us have issues. I just think that while some issues may be mechanical I really think this is due to changes in gas formulation and our cars apparent sensitivity to those changes.
I have changed my evap canister, vent valve, all vacuum related components, the pump, fuel filter, checked all lines for blockages and I still have this issue on hot days. ????
How close does the fuel return line get to hot components? I don't have the luxury of going out and looking at mine at the moment.
So, has anybody that tears their car apart more than me ever tried to test the amount of pressure that these new fuel pumps are putting out in comparison to what the service manual states? I'm still wondering if the fuel pump could be the issue.
With the return line blocked off (temporarily for testing purposes) and engine idling, my AC Delco pump produced roughly the same pressure as the stock pump. I don't recall what the pressure reading was though, just that it was about the same. The pressures also dropped a similar amount when the engine was throttled up, so I'd assume that means the flow was about the same too.
As a original owner of two third gens I can tell you for a fact they hissed when brand spanking new. this is because the whole system is designed to be pressurized. the issue scott has is no pressure and rough idle. mine is just a rough idle and stalling.
we have a lot of mechanical talent on these boards and very surprised that so many of us have issues. I just think that while some issues may be mechanical I really think this is due to changes in gas formulation and our cars apparent sensitivity to those changes.
All of my cars hiss when I release the cap - even days or weeks later but the tanks are not hot after I've taken a drive in them.
The stalling in traffic could be your injectors - when warm older (stock) injectors can/will go to a lean condition and you will stall out.
Watching this for the solution, I would be concerned about the hot fuel condition.
Their is a vapor Canister Purge Valve just before the Canister and conectes to the line that comes from the tank.
in my case the diaphragm lose all the rubber leaving Just the Mesh if this happend the diaphragm won't open because their is no seal an the vapors will not go to the canister and build up pressure in the tank until the vent Valve opens.
So I believe replacing this part will fix the problem all tho if the pump have taken it's tow it will be best to replace it too.
Ok, I tried something today that was posted in another thread I opened regarding the fuel filler neck when I replaced my fuel pump. I took the Vent Valve off and drove the car today. It was about 95* in Orlando, extremely humid and the perfect combination for the boiling gas. I drove around 40 miles in stop and go environments, and the filler neck never got hot. I was able to take the gas cap off and reapply it without issue. There was no hiss or pressure in the tank. Now, with the valve off, it was allowing air into the tank and also venting the fumes, so I still had the gas smell, but is very minimal.
What this tells me is that the valve is either defective (??) or the vent line to the charcoal canister has a blockage. I will install another vent valve that I know works and see if the problem continues. I'm thinking the issue is a blockage in the vent line to the canister.
Don't discount the possibility that the charcoal canister is bad. It's more about age than mileage. Old plastic, and old activated charcoal.... according to most sources the charcoal has a lifespan when in active use, of about 18 to 24 months. Remember that regardless of if the car has been run or driven the charcoal is exposed to fuel vapor. Charcoal has a serious affinity for petroleum - it absorbs it like crazy. It does not release it easily either. If your canister is original, I guarantee it would not pass functional tests for absorbing and releasing fuel vapor.
Also high tank pressure could lead to liquid fuel being pushed into the canister if conditions were right - high fuel level, cornering or braking just right, etc. Which would quickly ruin it.
Despite there not being a change interval, most manufacturers reccomended inspection every 24 months. I have seen them fail - plug up, crack open, and allow charcoal pellets to be sucked into the purge system. Which is a pain in the neck to fix involving attempting to blow impacted carbon pellets and dust from all the hard lines through the vehicle. And this is on MUCH newer vehicles.
Personally, as a mechanic, I just delete l that junk on my personal, older vehicles. Because I can and I don't mind the fuel smell. I also am acutely aware of all the extraneous emissions garbage failure modes and don't wish to deal with those future problems. Complexity is the enemy of reliability.... poorly designed 1980's plastic emissions equipment is the height of uneccesary complexity.... I reduce complexity at every opportunity and my life is much more enjoyable for it.
I don't delete that stuff on customers cars because it's both illegal and not in my interest to do so. When that money light comes on it's payday for me.
GD
Last edited by GeneralDisorder; 07-02-2017 at 08:05 PM.
I've disconnected the line at the purge valve, before the charcoal canister, and ran the car like that for awhile. I still had the boiling gas issue, so that tells me the venting wasn't getting to the canister. I think I have a blockage in the vent line. I'll blow it out and see if anything comes thru the lines.
06-16-2015, 11:53 AM
..........I wanna say the majority of the HEAT is coming from the return line from the engine. The engine/manifold/fuel rail is HOT. 
