Zeta_xsa

Hello everyone,
I hope this doesn't annoy everyone too much but I have some issues. First, I could probably browse this forum for hours like a retard and not find what I am looking for; I am not even sure what that is. So, here is the deal. I am a rising Junior at the United States Naval Academy in Annapolis, MD. One of the privledges of being a junior is the privledge to drive. Back in high school, I forced my dad to purchase a 1984 RX-7 S; a car which I love to death, but was ultimately an unwise purchase due to the condition it was in. My driving style doesn't help matters either. The car is currently with my parents who live in Cuba, MO, north of Rolla on I-44. My father is quite a capable mechanic, on piston engines, he knows pretty much nothing about rotary engines. I would like to find someone in the vicinity who knows about rotary engines and can give us a hand in getting this car into reliable working condition. The car works, however, it is not reliable enough for me to bring back to Maryland for I cannot afford to get stranded when I have to get back to the academy on the weekends. I know precisely nothing about automobiles; I am a systems engineer, not an auto mechanic. I asked my father to contribute what he could to this post, in giving some opinions of what he thinks is wrong with the car. As far as I am concerned, the engine and carburator need a lot of work, possibly rebuilding. The interior needs to be replaced because it smells of gasoline, but that will do not good if I do not eliminate what is causeing the gas smell to leak out in the first place. The A/C also does not work. Here is what my father has to say about the vehicle:

"Our biggest problem at least with the engine is the fact the it seams to have a sort of a miss at idle, maybe you could call it a fluxation, if it reved up and the accelerator released it tends to back fire, I suppect distributor or timimg or point gapping, just not sure ... there is also what appears to be an 02 sensor in the exhaust pipe that has a wire bread wrap and it is broken into, I know that is causing a problem but I don't know what ... also want to retro fit the A/C so that it will use R134A refrigerant, a lot cheaper then freon, The A/C has leaked all the freon again so I need to find where the leak is and get it stopped ..."

Thats all my father can think of at the moment, I looked at the first post with some shop listings and took down the place in Neosho, but any other ideas, help, ANYTHING you have to contribute would be greatly appreciated. I really need this car by mid July. Not driving for 2 years really sucks, I am getting ichy.

rfburris

I am the father of the of the person who posted the message above and will be able to monitor responses and help with my greater mechanical knowledge, experience and understanding. Thanks to all in advance.

the_real_bill

Hey Ronald

First things first, i want you to know that i am relativaly new to the RX-7 world also!
However, everyone in this fourm will tell you the same thing--------all RX-7s backfire!!!!! there are steps to take to reduce the backfiring, but, the only way to get rid of the backfiring completely...... is to sell the car!!!!
It is one of the characteristics of RX-7s.
I was worried that there might be something wrong when i got my 7 too. But, i was quick to learn!
(i own a 84GSL)
Now, does the backfiring sound like a loud-------- BANG BANG put put put put
or is it more like a quieter---- POP poof poof poof

Also, where does the car idle at??? 900-1000RPM or 600-700 RPM???

The "miss, at idle" Does the engine seem to want to stall or is it just a small little "put put" noise???

The O2 sensor, has me a little bit confused!!
I didn't know 7's had O2 sensors.
So, i'll let someone else try to field that question.

As for the A/C....... i wouldn't even worry about it right now, if i were you. Leave that mess alone until the car is in good working order.

~Vince~

neo_omega

this will get more responce in 1 gen tech.

jeremy

iTrader: (1)

the miss sounds like a vacuum leak somewhere in the rats nest. that is also a problem i'm having. the backfiring is normal but can be pretty bad depending on timing and the spark power your ignition has. i advanced mine and my putt putt has turned into blowing the muffler off backfires. as for reliablilty, pack knowlege and a tool box, lol. these are very quarky cars. and make sure the battery is tied down well.

error402

Zeta_xsa and rfburris welcome to rx7club.com!

neo_omega thanks for moving it in the correct forum.

Don't worry about annoying people on this site. If they tell you to use the search feature, just happily raise your right and stick up your middle finger and smile in their direction (figuratively speaking of course).

Okay back to the problem...

- where does the car idea at?
- have you done a compression test on the engine yet?

RX-7 are notorious of backfiring, matter of fact if you have a straight pipe exhaust you can get flames. Some people think it's "cool" to watch. It doesn't seem to do any major damage, so people live with it.

- Check the timing.
- Check for vacuum leaks with the emissions equipment.
- Also it doesn't hurt to have the coils, spark plugs, distributer cap, and distributer rotor replaced if they are still original.
- Make sure your not running a rich fuel mixture.

the_real_bill - RX-7's have oxygen sensors it just depends on what year your dealing with. My '83 GSL does not but my '85 GSL-SE does.

jeremy

iTrader: (1)

oxygen sensors are for fuel injection. that is why most of us don't have an answer on that since your car is carbed. glanced thru the haynes but didn't see anything either.

Zeta_xsa

Thanks for the help guys, I originally posted in the regional forum to help drum up some local support. I was gonna post another in here, good thing I didn't. I will get my dad in here to answer your questions about the tech. As for what I know, we have not tested the compression. I don't think either my father or I know what a "good" 1st Gen is suppost to sound like, he might like to argue. He can tell you where the car idles at, as best as i recall its like 800-1200 I think and its not a steady idle, its up and down at idle. Oh yea, this might be a important fact, this badboy has like 160K miles on it. I don't know what components are original, I am pretty sure the engine is, but I think we replaced the distributor not too long ago (from a junker, so that might not help). Also has new starter (yipiee, like that makes a big difference). Anyway, thats all I can really contribute for right now.

MyRxBad

I can see this msg is going to be a mess with all the different skill levels of a lot of members.

First Off: Rotary engine should not backfire. Cat or no cat. Backfiring rotary engines lead to blown apex seals (the seal that holds compression in the housing). Either that or you start breaking spark plugs prematurely.

Other then that, you are going to have to provide us with details on the car, like is it carburated still? Any modifications on the car. IE Fuel injection, headers?
Rear drums or discs?

But regardless check the basics first. Spark, Fuel, Air.

mar3

iTrader: (8)

...and Air Control Valve which is the main reason stock carb'd 12A's start to back fire. Get a Haynes manual, it'll be a greater friend than you realize and post pics of the areas causing concern so we can see them. It helps a lot....

DONNA

info, http://mrmazda.members.atlantic.net/...t.html#NOSTART

hanman

Before I read further, please note ALL RX7'S DO NOT BACKFIRE. THEY ARE NOT SUPPOSED TO. If they were supposed to they would come that way new from the factory. And as an owner of an 80 RX since new, I can tell you they don't.
Reasons for backfiring:
1. Hole in the exhaust system somewhere. This is the most common.
2. ACV valve malfunctioning. Also very common.
3. Timing. If you haven't touched it, it is unlikely.
There are more, but this will get you started.
Now after my rant, I will go back and read all of the posts again.
hanman

Defprun

I think they meant, by backfiring, that "thud thud thud" that comes when you release the throttle. I don't think that's actual gun-shot backfiring, just sounds like backpressure or something.

But, since I don't really know any other carbed 12a's around i have no comparison except for a mechanic around here that deals with them accasionally...for 15 years. But he doesn't want to do that anymore

hanman

OK here is where we start:
1. Do a thorough tune up. Rotaries are more susceptible to this than a piston engine. This means, plug wires too. Rotaries eat plug wires. Don't scrimp on the wires, Moroso are good, do a search. Be prepared to pay. NGK's are affordable and will last for a while. New plugs, rotaries foul plugs just for fun. New dist. cap and rotor. New fuel and air filter.
2. The advice above about the vacuum hoses is sound. It is very common on these cars to get vacuum leaks. Then you will usually have erratic/high idle problems. Being a mechanic you will know how to find these, WD40, water, propane, whatever your choice is. Check the hoses around the base of the carb, they are common problems. Also, check the large hose coming off the backside of the intake manifold. This is the brake booster line, if it leaks it creates havoc.
3. By the way, your car does not have points. It is an electronic ignition.
4. O2 sensors came with the GSL-SE's, on the other models I don't know for sure. I added one on my 80 to set the carbs idle. If it has a 02 sensor, it will be a one wire sensor. Easy replacement at the parts store.

If you want to check the compression do a search using my name and the word compression. It will show you how to test a rotary with a conventional tester. I wouldn't bother if the car is starting ok.

General rotary wisdom:
Change the oil every 2 to 3k, without exception, and never let it get low. The rotary engine runs SO much hotter than a piston engine, and it uses the oil to cool it as much as the coolant system.

NEVER EVER LET IT OVERHEAT. It will kill the car in a heartbeat, see above. Flush it every year and install ONLY A MAZDA THERMOSTAT. Do not buy a thermostat from the parts store.

NEVER take the car to a Mazda dealer, they know less about the car than you do. I am serious. Unless you can find an "old school" Mazda mechanic. They are few and far between.

Buy a Haynes manual before you do anything else. Usually, you can pick one up at the local parts store. They are on ebay all the time. You should be able to pick one up on ebay right now for less than $12 including shipping. Do not buy a Chilton's, they aren't worth the paper they are printed on. A factory manual is also very handy.

Do the tuneup and come back and post the results, we will help all we can.
Dave

Zeta_xsa

Ok, wow, this is great. He is my 2 cents, trying to get my dad in here to respond to the high-tech stuff. As far as basics from me: the car is stock, no performance mods of any kind (thats later hehe We have had the Haynes manual for some time. And I am going to agree with defprun on the backfire issue, its a fairly small put-put-put when returning from acceleration. NO regular gunshot backfires. The only time its done that is when i turn it off while the choke is still on, which i just read was a very bad thing, dont do that no more. Thanks..