As my next step to try and solve the fuel problem on my '83 12a with Nikki, I'm going to drain the fuel tank. Rather than remove the tank, I'm going to disconnect the fuel line from the carb and let the fuel pump do all the work.

Question. What is the spec on the fuel regarding the inside diameter? I want to add a valve fitting to the end of the line and then extend a longer line into a gas can.

Thanks.

 

it would probably just be easier to jack the car up and unhook the hose from the hard line under the car. that way you don't have to get a new length of hose.

 

Pumping the tank with the fuel pump will not get all the crud out; much will stick to the bottom of the tank as the fuel level drops. Only way to thoroughly decrapify a tank is to drop it and have it cleaned.

If you're just suspicious of bad/wet fuel, it should work OK.

 

"wmelon137: it would probably just be easier to jack the car up and unhook the hose from the hard line under the car. that way you don't have to get a new length of hose."

Thanks guys. After I posted, naturally, I then did a search and found how I could drain the tank without my screwy method. My first suspicion is bad fuel, so I'll see if that works. If not, the tank gets dropped and cleaned.

 

i'm not sure, but 83 might have a drain plug on the tank.

 

Nope. Only 84-85 Models do. :-)

 

If you actually post what the running issue is then perhaps you could be pointed in the right direction.


Are you running out of fuel under hard acceleration?

If you suspect a "Fuel" issue then perform a fuel quantity/volume test. Specs are in the FSM.

You can also troubleshoot per the Carburetor FSM if you suspect you are having a "Fuel" issue.

 

if you are going to go the routs of dropping the tank, i have a writeup on tank removal. though the only difference will be that you cannot drain your tank with the drain plug as stated.

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 te 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:

 

Very strange. My 83 has a drain for sure. Ive used it twice since Ive owned the car. Im pretty sure its an earlier 83 also...

~T.J.

 

my 83 also has a fuel drain plug. But I disconnected the fuel line in the engine compartment, and used the fuel pump to remove all the fuel. It was a super tight (no fumes or splashes) way to do it.

The top of my tank looked nothing like the tank in the write up. None the less, the removing the gas tank right up was dead nuts on.

I checked my removal reinstall of the gas tank by checking the flow rate of the fuel to the carburetor.

Also my 83 rx-7 has the drive shaft to transaxle fitting of a 82.

 

I don't remember any 83's having the drain plug for the fuel tank. I'll have to do some research on this.

 

Doc, I am the original owner of this '83. Bought it new from the dealer and still have the original sales brochure and window sticker. That's the good news. The bad news is that I parked it about 5 years ago to go to work on a '72 Vette. Sold the Vette last year and decided to resurrect the RX-7. Interior is perfect. Paint is oxidized and it needs a RF fender. About 8 years ago I put in a Mindspring header and exhaust system which were the only mods.

Before attempting to start it, I changed oil and coolant, replaced plugs, plug wires, rotor, cap and coils. The clutch master was shot so I replaced that. It started up and ran for about 20 seconds, then died and the clutch pedal went to the firewall.

Attempted to replace the clutch slave but that was a futile effort so I bit the bullet and took it down to Wolfgang at Coyote Motors here in Boulder. He had worked on the car almost from the time it was new. He replaced the clutch slave and I asked him to look at starting probs.

Well, I had "forgotten" to drain the gas tank (about a 1/4 tank of gas) and he diplomatically pointed out that 5 year old gas was probably a little stale. Duh! The carb was also coated in varnish and the fuel pump was weak. I gave him the green light to rebuild the carb and replace the fuel pump.

I filled the tank with super premium mixing it with the remaining old gas, which I'm convinced was a bigger than big mistake. She will run strong after starting for about 20 minutes and then start missing and losing power. Won't die, however. I can pull over and sit for a few minutes, start up and run again for another ten. Then I repeat the whole dance.

So, I'm going to start from the "back" and drain the tank completely, replace the fuel filter again and see if that helps. My next suspicion would be the carb rebuild.

Any other advice will be greatly appreciated!!!!!!!

Thanks.

 

how about getting down on your hands and knees and look under your car for the damn drain plug. It's 15 mm socket size.

And the ID of the rubber fuel line to the carb is 5/16's. Or you can ask the auto parts guy to look at it to get a gestimation.

Also the symptoms of starting up, and running fine for 20 minutes and then showing fuel starvation point to the fuel filter.

 

I like your attitude!

Neither Haynes or the factory service manual mention a drain plug on the tank - they describe the fuel line at carb dump procedure. But, I was going to check under the car to see if there is a plug there. Hope to do it this week-end but have some important time carved out to be at Bandimere for the Mopar Nationals.

 

I know you damn well are not directing this statement at me!!!!!

 

Just checked the FSM and it shows a drain plug on the bottom of the tank for the 83 models.

Now I have to see if the 82 does or does not? Maybe that is the cut off year?
Just verified that 83 is starting year for the drain plug. 79-82 do not have them.

Sorry for the misinformation and thanks for the heads up on this guys. :-)

 

my 82 does not have a drain plug.

look in the parts catalog, its more accurate

 

Sorry, meant to say parts fiche as that is what I looked in to confirm this. ;-)

 

ok, let's have an official poll of rx-7 83 owners on who has a fuel drain plug, and who doesn't....or we can have national get together and have a competition, darts, volley ball, foot ball, paint ball, duelling pistols, or races (car or otherwise)......will an aftermarket drain plug make my car faster than the OEM?

 

ok, enough with the "will an aftermarket drain plug make my car faster than the OEM" and such. lets stay on topic and not direct any statements towards other people that will **** people off, disrespect them or make my banhammer come out...its rare that i will give an infraction but we have a great group here in the 1st gen section and there's no need to be short with one another.

its verified that all 83 model years started the drain plug on the fuel tank. its a 14mm head on the 84-85's, 83 may be a special deal with that. i know the early build 83's did not have the "ribs" on the strut tower and the late model 83's did, as did the 84-85 model years.

 

Not that it matters, but mine is an 83 with a manufacture date of 11/82. It does not have a drain plug.

 

^^ good info to know. does your 83 have the ribs on the strut towers?

 

Well, I'm guilty of felony stupid posting without looking at my own damn car! Got underneath today and lo and behold, there's the fuel tank drain plug. Guess this might help solve one of the discussions here. Car is almost bone stock, '83. It's a 14mm bolt.



Here it is in action.



Changed the fuel filter. This one has only seen about 30 miles on it. A thick yellowish gel filled the bottom. It quickly dried.



Here's the top part of the filter.



Drained the tank completely. Replaced the fuel filter again. Added about 2 gallons of new gas. Just started out on a test drive, heard some banging under the car and found an exhaust pipe bracket had broken! Oh well. The complete test drive of the fuel system will now have to wait.

 

well, keep us posted. hopefully you will be able to resolve your issue. though, seeing sludge on teh inside of the filter like that makes me wonder what the inside of the tank and the fuel pump look like..