lilrams09

Hi guys,
Been a while since i was on last. I use to have a 79 rx7, I ended up selling it because i could never get the car to run right. Couldn't get it to idle the way the it should of been, it was either a high idle and no hesitation or correct idle and you couldn't take off because the car would die when you gave it some fuel. If you were driving it the car it was very bad for just up and dying. It always was worse if you were running the car kind of hard. When it would quit it basically felt like the car was running out of gas. It would sputter and spit and there wasn't anything you could do to keep it running. Once it died it might fire right back up or it may take a day of sitting and then it would start right up???
So long story short last week i ended up getting a chance to get the car back and I snagged it. i'm fairly certain the car hasn't been drove in about 5-7 years. When i got the car it had been sitting for 9 years in a heated garage though. it's got around 95,000 Miles on it, and my main questions are, what would be causing the car to die like it was? Since i'm coming into winter i want to go through the car and make sure i don't have the issues i had before with it. I'm use to working on piston engines but how much different are these cars? i'm wondering from what i have read on here if the Apex seals are bad and causing the bulk of my issues? If that would be the case how difficult are these engines to pull apart and rebuild, i'm assuming slightly easier than a large diesel engine or gas motor?

Any advise would be great. i know this is kind of a vague description of the issue but like i said its been a few years since i got in it and i know no work has been done to it since i let it go.

Thanks!
Chad

Jeff20B

iTrader: (13)

You've come to the right place!

There are a lot of amazing mods you can do to these cars. They improve drivability and idle quality a lot. It depends on how much you want to do and learn.

TheRX7Project

iTrader: (3)

Welcome (back?). The symptoms you describe do not sound like apex seals, but we'll get you on the right path. It sounds like it probably has a fuel issue- I had a Jeep that did the same thing. The fuel tank was corroded inside, and as the jeep ran, rust would build up and plug up the gas pickup tube. When you shut it off, it would release the rust and drop it down to the bottom of the tank.

First thing you want to do is check for compression. Pour a little oil down all the intake runners (Marvel Magic Oil is best), pull the plugs from the front housing, and crank it over. You should hear 3 distinct "chuffs" as the engine turns over. If you hear a small "puff" rather than a "chuff" then you know *something* isn't right internally. Do the same for the rear rotor. It may take a few cranks to get the oil into the housing and sealing well. If you hear 3 good "chuffs" from each rotor, your apex seals are good and more than likely the engine WILL run.

Next thing is spark. I'm assuming since you mentioned working on piston engines, you understand how to check for spark.

Last but certainly not least is fuel. Having sat for years, the fuel is likely junk and the carb may or may not be all gummed up. What I would do is remove the fuel line going to the carb, put it in a bucket and turn the key. This will pump out all the old crap, and if it doesn't, then you know your problem is a clogged fuel line, filter, pickup, or a bad fuel pump. While doing this you can try to start the car by hooking up a fuel can to a line going to the carb, and holding it up high as to "gravity feed" the carb. Shoot some starting fluid down the carb and try to fire it up. If it tries to run, at least you know your problem is isolated to the carb. If it runs, great, then you really know the problem lies in the fuel system before it gets to the carb. If not, well, there are plenty of people here who can help you replace that carb, with either a used or rebuilt unit, or an aftermarket carb setup.

Good luck with your project, there's plenty of help to be had here.

7aull

iTrader: (2)

Welcome back Chad-
I am going to add to what info you have been given here, esp re fuel system; in particular, the condition of the tank's innards. As said by others, I believe you need to address the condition of the inside of the tank beyond anything else you try, because this is likely "a" cause of your problems, if not "the" cause.
I would be concerned that anything else you do without addressing the tank will likely put you right back where you were when you finally dumped the car the last time. I had similar issues in my 1980 as well. The whole fuel-supply chain was suspect and swapping pumps, filters, purging carbs never quite solved the problem - till I pulled and cleaned the tank! The fact yours has now sat an additional number of years, likely with old gas, has not helped.

The 79-80 tanks need to be drained manually, in that there is no drain plug (till the 81s). You want as much gas out of the tank as you can, since they get pretty dicey to handle with much gas inside as you drop them. I pulled the fuel level SENDER (passenger rear fender, behind a cover in the wheel well) out to get a hose in to drain most of it. You WILL want a new sender gasket standing by ! (still available). The tanks are held in by 2 straps and 4 bolts, bearing in mind you will need to disconnect the fuel filler rubber hose. And be warned that there some 4 different fuel hoses attached to the TOP of the tank and you will wan to carefully (pics!!) document which hose attaches where!!

Once the tank it out, get it to a competent Rad shop that can dunk it in a cleaning tank to get the old scunge out of it. At this point in the life of a metal tank, with 1000s of cycles of partial gasoline and air mixed to create a lot of condensation, the insides will have some degree of corrosion, which I think is the primary (and unending if not treated) cause of fuel problems.
With the tank properly cleaned I recommend a product like POR15's Gas Tank Kit ($30) which is a metal-prep, then a sealer that you basically pour in, slosh around, then dump. Point here is not just to CLEAN the tank, but also to SEAL it so this does not happen again!

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As to the condition of Apex seals - let me further add that there can be compression issues (as in, a lack of) if a seal is carbon locked into its groove, and therefore not allowing the spring under it to correctly press against the housing = lack of compression. I have found once of the best things to free up carbon-lock is SEAFOAM, which can be dumped right into the housing, and you can manually crank around the motor to get it where it needs to go. Then let it sit a few days. Utterly harmless to the engine but a great product to remove build up. As a follow up I always add a can into a fuel tank once a year as a road-going "tune-up" since it then runs thru the whole fuel system as a cleaner, esp the carb. Great for fuel preservation too!

Best of luck - keep us posted.
Stu Aull
80 GS, AZ

lilrams09

Sorry for the silence, took a while to get out to the car and mess around with it.

So it's set for around 7-8 years, i push the car out of the garage put a battery in it and hit the key. The car needed a little shot of starting fluid but started right up. is it normal if one of these cars sits that long to smoke an absolutely insane amount?
Long story short the car ran just how i remember.... idled up around 1200 RPMS, didn't want to take off very good at all. meaning you couldn't just let the clutch out and the engine would handle the load of taking off.. you had to ride the clutch slightly. also it wouldn't rev up much past 2,500 without pulling the choke a little. If you tried to pump the gas or anything it would stutter and hesitate. The worst part that i can't figure out, is if the car died, like i stalled it or hesitated to much and i couldn't keep it going. the car wouldn't restart. I would cycle the key, 2 or 3 times then it would fire up. almost like the fuel pump had to prime the carb back up?

All this stuff is exactly how the car acted when i parked it. So i'm pretty certain it needs a serious look into the carb and maybe some upgrades to the ignition system. So after doing a little research, i found an article on stripping the junk off the carb to help it out. i've read a bunch about a sterling upgrade to the Niki thats on it. and also a lot about the webbers. Let me know what you guys are thinking on the carb side of things. I would really like to get something on it to make it run a little better but nothing crazy. it's still going to be a cruiser i just would like to have a little speed when i want it.
I'm also going to go through the fuel system, put new lines on it and clean the tank so i don't mess up the new carb when that time comes.

let me know if you think this is on the right path to getting it back to good running order.

Thanks,
Chad

Banzai

iTrader: (13)

It's not abnormal to have a little smoke upon startup, but an insane amount points to an internal leak somewhere. Maybe it just needs a new set of soft seals. Don't get confused just because it has rotors that go round and round instead of pistons that go up and down. It's an internal combustion engine that is fed by a carburetor. The fuel system / carburetor is where your stumbling and idle issues are. If you are leaking coolant internally (the smoke) that will add to the problem. Rotary's are designed to burn a little engine oil (the OMP) but not coolant. Sterling isn't building carbs anymore, there are other options, the "Fat Nikki" is a good way to go and keep your original carb.

t_g_farrell

iTrader: (1)

My advise is to first get what you have working properly without doing any mods or upgrades. You have a fuel delivery problem. Starting with dropping the tank and replacing the lines is the first step. Once thats done make sure the pressure and volume of the fuel pump is up to snuff all the way to the carb. Then go through and make sure that all the vacuum lines are good and not cracked or loose. At this point you should probably rebuild the carb, just don't use the new needles and seats or try to add gaskets to the baseplate. The new needles and seats are not very well made and tend to cause flooding issues and the baseplate has permanent gaskets on each side, so try not to mess em up. Also don't mess with the floats unless they are out of spec via the glass site plates on each end of the nikki.

Use this thread to track this and we can keep poking you with ideas as it goes along. Welcome back.

lilrams09

Is that too much smoke?
Remember we are talking about 7-8 years of never cranking the motor.
It quit shortly after that.

KansasCityREPU

iTrader: (9)

If that smoke does not subside after 10-15 minutes then there is an issue. That looks an awful lot like water smoke. It will smell sweat and if you put your hand by the tailpipe you can feel the condensation.