Ok i have a problem here, and a couple theory also. Im getting off the freeway yesterday after doing 110 the whole way to my destination and back which is maybe 35/40 miles each way. im turning right off the freeway, and it just horribly smells of gasoline. i had just filled up before hitting the freeway home. i get back home turn right into my driveway and pull up. get out and theres a trail of gas running up the driveway i open the filler door the cap was half off. i swore i closed it. i look by the filler neck and it looks to be seperated , not bad and it might not be cracked. ok now some theory, ive been premixing, oil left insde the filler neck be causing rubber to get soft, another one, the car will run hott on the freeway, it will run all the way up to the line 3/4 of the way up the gauge, maybe the gas is boiling causing tank pressure to increase and it blew the cap off, or allowed neck to crack. #3 it could just be because of the cap not being on in the first place. 4# just driving the damn thing with alot of vibrations and big michigan pot holes caused it to crack. the gas gauge dosent work, so im gonna have to fill it up to see how much fuel i lost and if the cap on does the job, it seemed to driving home, but there might not be fuel in it. thanks

 

I think that is just karma getting your *** back for driving like a douche!

Knock that **** off!!! Then post on the forum with a question

 

Listen its not karma,because i drive fast im a douche?no one on these forums have ever gone 110? including you mr douche bag himself mattg.. I drive like that knowing problems will occur it dosent bother me,and i am willing to take the consequences. you dont hear me making a big deal about the cracked tank, i was just wondering if anyone has had it happen before, if what im thinking makes sense, if the cars have known problems with gas tanks cracking. so thanks for the worthless information.

 

Well...I'll try to be helpful because I think I may be having the same issue.
First if you haven't downloaded the FSM I'd suggest you do so.
http://foxed.ca/rx7manual/85_manual.html
Next accordingly download the Fuel and Emissions section.
Search for the section on the Crankcase and Evaporative Emissions Control.

I would try to find the check valve and make sure its not blocked because that could be causing excessive fuel tank pressure. My issue is I have to pump gas slowly or else it will stop the pump regardless if the tanks empty or not.

 

you're looking at it all wrong. It isn't the consequences you're willing to accept we're worried about, it's the consequences other will have to face against their will that matters. What would you do if you popped a tire @ 110mph, and it caused you to swerve over a few lanes out of control and hit a car with a child in it. Could you honestly feel right when you're in court and you see a crying mother who is trying to settle a case where you took the child's life? Driving isn't just about you, you share the road. I am also on the bandwagon of not helping people when they post up that the problem occurred doing stuff like this. Find out the problem yourself, I'm sorry but that is just too selfish to warrant actually deserving help.

And to let you know, I have never cracked the 100mph barrier in any of my Rx-7s on the road.

 

My temp gauge never reaches 1/3 of the way up no matter how I'm driving her. Doing 110 with other cars on the road is just dumb. I'm not saying you cant drive your car fast. just doing it on crowded freeways is dumb. I'm a big fan of windy country roads. I try and keep it under 3 digits though. 60 to 70 around a tight bend is enough to get a grin on my face.

I'll help you with one thing drivng you car at those high temps will blow your engine. its probably already not rebuildable from the damage youve already done. If your not going to take care of your 7 go buy a civic. or somthing that theres enough to have someone destroy.

Be smart, if you kill somone drivng like a idiot you will go to jail.

 

You came across like an idiot. Maybe you gave the wrong impression. In my opinion, the fact that you have a known issue with your car (overheating) and continue to drive it like a jackass even though this could easily kill your motor, does indeed make you a jackass.

But perhaps this is all just a misunderstanding, and everyone is getting off on the wrong foot here. Perhaps you can change our minds?

 

ok couple things who said it was a crowded freeway, i never gave a time, just dont put words in my mouth. the motor dosent smoke atall on startup, has 110 psi on both rotors rebuilt about 35k miles ago. i dont think the motor is bad, i have 3 other motors i can put in if its "bad" . as far as the heating goes when i slow down the temps come down.it could just be the fan is getting weak, what is that line there for in the first place? they just put that there for no reason then then line before hott then hot? plugs look a little white so it might be running lean causing it to get hott. all these "WHAT IFs" your tire popped while doing 110 on a crowded freeway and your car flipped over 9 times causing a 300 car pileup "THIS COULD" happen, who cares you guys sitting here calling me an idiot isnt gonna change me driving fast PERIOD. I would how ever like you guys to help me with this problem at hand, my leaking gas tank. i do also have 8's not 9's for plugs so it would run hotter at high speeds.

 

And for a little more help on the heating issue, the thread under 1st gen that reads "gauge readings" will show your that my car was running at temp at leat according to the guy who posted the pic with all the neat lines, so all the "your running your engine hott your an idiot can stop"

 

Cool, like I said, a misunderstanding. Now everyone can get back to troubleshooting, right?

The overheating won't be the fan, that only has an effect at low speeds and idle. Freeway speeds you're getting all of your airflow from, well, your air flow. The fan has no effect. Make sure the water pump belt is not loose. Maybe consider swapping to a cooler running thermostat. Could be looking at internal blockage of the radiator, so maybe consider an upgrade while in the process?

For the gas tank, you found that the cap was not on all the way. That kind of explains it, doesn't it? Your theory of the gas boiling and blowing the cap off does not hold water. If it continues to be a problem, even with the cap fully in place, then we can continue this part of the conversation. Until then, unless I have misunderstood, you have already solved it.

Hope this helps.

 

Not directly... but you're painting people here into the logical corner that says, "if we don't help you fix your car, you probably won't be driving it for long."

Food for thought, yes?

To your specific questions:

No, oil can't dissolve rubber that is gasoline safe.

No, the engine running slightly hot (below the end of the safe range) can't boil gasoline fast enough to effect fuel pressure, much less "blow the cap off."
"
No, your 'fan' being weak would make no difference in cooling while travelling at speed down the freeway - - the fan really only comes into play when there's no airflow thru the radiator.

The odds are a lot higher that you just didn't put the cap on right, but you shouldn't be filling the tank so full that gas can run back out the cap anyway. Especially after driving any distance at speeds like that - - you were probably burning thru a gallon or so every 10-15 miles, minimum

If you think you have a cracked filler neck, it'd be pretty stupid (as in, wasteful and dangerous) to fill it up with gasoline to find it; especially as you may need to drop the tank to fix it, which means having to drain the tank first.

Investigate visually. The leaking gas should have left a pretty obvious trail to the origin.

 

The only reason for it running that hot at speeds (you'd be turning about 5K
in 5th gear I think) is that your cooling system is weak. Either the radiator has
blockage, your waterpump is weak or theres one other thing no one else mentioned yet.

Do you have the under pan on the car? Thats the pan that seals up the engine
bay from in front of the radiator (and under it) to the crossmember. If that pan is
not there you will run hotter especially at those speeds because now the air has
stopped going thru the radiator and is going around it. BTW running at 3/4 is a very
bad sign, no way your gauge should get that high. I would pull over in a heartbeat
if my gauge was up that high.

Your fuel issue sounds like a loose nut behind the wheel. Put the cap back on and
tighten the neck back up and see how it goes. Theres no way pressure in the tank
can blow off the cap, more likely that much pressure would blow a line off somewhere.
I've never heard of these tanks cracking or beaking open. They can get rusty and rot
apart tho and for a 30 year old car thats not unlikely.

 

Joined in May-09, drives 110mph for 35-40 miles straight through, and engine running beyond the HOT range - can't figure out why...?

Welcome to the boards!

 

Please read the whole thread the car is not running hotter than it should be , if the other thread on here is correct it is running in the safe range. LETS NOT WORRY ABOUT THE MOTOR RUNNING HOTT BECAUSE IT ISNT OK, DONE. Now the tank. it looks like its coming right from the neck. ill snap some pics.

 

Mods delete!

 

Maybe someone saw you doing 110 on the freeway, followed you and decide to f with your car. there are crazy people out there
slow down and enjoy your 7. fix the issue and take her to the track.

 

Translated: "oh crap, I did leave the cap loose...!"

Don't let it get to you, son; everybody gets one.

 

no the tank is cracked by the neck, it trickels out when i poured a little gas in.once again some douche on here puts words in my mouth.

 

Hey, maybe the gas in the tank boiled because you were driving faster than the speed of sound...

Have you considered how stupid it is, to be insulting the same people you have been asking to explain very simple mechanical principles to you?

Good luck, there, Skippy.

 

first off, calling fellow members douches will get you a temp ban pretty quick. so, with that said, this will be your last and final warning for the insults. i won't hesitate to stomp this behavior out. this goes to all of the mudslingers. this is a tech forum. leave that crap in the lounge.

ONTO YOUR PROBLEM. the filler neck may be cracked as you mentioned. if i were you, i would remove the tank and inspect it and it's extrenal components for wear, rust, or cracking on the lines. i will provide a writeup on how to drop the tank. this will aid you in removing the tank and further diagnosing your problem.

 

here's some info and my writeup on dropping the tank should you need to do that. others may do it differently, but this is what i've found works. dropping the tank is no big feat. just make sure you drain all of the gas first. it makes a big difference when removing and reinstalling the tank. pop open the filler door and remove the three 8mm bolts holding the filler neck on. push the filler neck through the opening. it may be a little tough at first but the seal will unstick and it will push through.

next, get under the car and remove the three lines ahead of the fuel tank. eaiser to do this now rather than when the tank is coming down. then you'll want to remove the small plastic splash guard in the left wheel well. this will give you access to the sending unit. unplug it. chances are the connector will fight you a bit coming off and will be stiff. be patient with it.

you will then want to remove the two 14mm bolts holding the tank up, move the straps down, and work the tank down. get the tank on the ground and remove the pickup lines and the fuel level sender. you may find the screws for the fuel level sender very rusty and difficult to remove..of course you are in NC so i doubt that thats the case... you can now look in the tank and make a determination of where you want to go from there. when the tank is clean you will want to replace the gasket for the fuel level sender and the gasket for the pickup lines. you may also want to replace the pickup screen that attatches to the pickup lines. this can be clogged or ripped or otherwise in poor condition. the part numbers for replacement parts from mazda are as follows:

pickup/return line gasket: FA54-42-182

fuel level sender gasket: 8871-60-962A

pickp screen: GA97-42-113

fuel tank pad: 8871-42-761

fuel level sender(if yours is bad. new sender comes with gasket): FA54-60-960

i have recently purchased most of these parts for my project and the prices are pretty reasonable from the dealer.

pics to follow with explanations.

 

here are the instructions with pics for the tank removal:

first, jack the car up, put it on stands, remove the left rear wheel, remove the plastic splash shield in the left wheel well. it is held on by two 10mm bolts and a 10mm nut. this will expose the fuel level sender which needs to be unplugged at this step:



next, open the filler door, remove the gas cap and the three 8mm bolts, lift off the plate and push the neck down until it breaks away from the body:



now is a good time to drain the gas. place a suitable bucket under the drain plug and remove the drain plug. a clean 5 gallon bucket works great and you can empty the bucket into a 5 gallon gas can or cans:



after the tank is drained, reinstall the drain plug and remove the clamps from the feed, return, and vent lines and slide the hoses off:



once thats done, remove the 14mm bolt from from each tank strap, they'll be in the front of the straps towards the rear bumper and you'll want to swing the straps down:



when the tank starts coming down, wiggle the filler neck out of its opening. once you do this, the tank will finish coming down(all the while you are supporting the tank with your leg or suitable support i hope)



and the tank will be down and ready for service:



once you are satisfied with the tank, install is the reverse of removal. wiggling the filler neck into its opening while installing the tank at an angle is the toughest part. once everything is set in place, you'll bolt the straps up, install the lines, install the filler hose and cap, connect the sender connector, install the splash shield, install the tire, lower the car down, fill the tank with gas, start, and check for leaks.

here is the new pickup gasket and fuel level sender with screws installed





reinstall the tank and add a coat of undercoating to preserve the sender and protect it and the screws from rust. you may also want to clean and undercoat the entire top of the tank while it out to preserve it:

 

I don't understand what your issue is Zukied. I tried to derail the bitching and get the thread back on track, but you seem determined to bite the same hands that are offering help. I see you are from Michigan, and I'm trying to remember if we have met, but can't recall. Anyway, I will work under the assumption that you are a decent guy who is still stuck in a misunderstanding.

People are getting frustrated because all we can go by is what you post, so if you tell us something we have to assume that it is true. But when we quote you, you come back with flaming comments about douchbags putting words in your mouth, etc.

Lets take a moment to review some of the things you have written up to this point, keeping in mind that members are offering you useful information on troubleshooting your problem at the same time you are posting this stuff:

get out and theres a trail of gas running up the driveway i open the filler door the cap was half off. i swore i closed it.

another one, the car will run hott on the freeway, it will run all the way up to the line 3/4 of the way up the gauge, maybe the gas is boiling causing tank pressure to increase and it blew the cap off, or allowed neck to crack.

including you mr douche bag himself mattg

I drive like that knowing problems will occur it dosent bother me,and i am willing to take the consequences.

who cares you guys sitting here calling me an idiot isnt gonna change me driving fast PERIOD. I would how ever like you guys to help me with this problem at hand

Please read the whole thread the car is not running hotter than it should be

LETS NOT WORRY ABOUT THE MOTOR RUNNING HOTT BECAUSE IT ISNT OK, DONE

once again some douche on here puts words in my mouth.

So, can you begin to understand why some members are getting a little short of temper? Anyway, like it or not, you've ended up picking a fight on the internet. Either run away crying, sell your 7 and never come back again, or apologize for any offense (real or perceived) and carry on with your troubleshooting process like an adult.

End rant...

 

This doesn't seem to be getting anywhere. I'm going to close this.

For the tank problem, best I can tell you is to drop the tank and inspect it. You may have had a weak spot on the tank and possibly also have a venting problem allowing pressure buildup (or more likely vacuum) in the tank causing the weak spot to fail.