RX7 noobie PLEASE help with diagnosis
 

I have just been lucky enough to get an 84 RX7, but I need help with it, I know absolutely nothing about rotary engines. The car starts easily, it is "drivable" but you have to accelerate VERY gradually, even in neutral, the car won't rev high, it will sputter , and backfire through the carb. When I first got it (yesterday) it wouldnt idle unless you held the choke on. What I've done so far is install new plugs and wires, I adjusted the idle and mixture screws on the carb. And set the timing as per the Haynes manual. It does idle now, but it still has no power, and won't rev up. It will get to 60 MPH, but it takes about mile to get there. It has very good spark, it doesn't smoke. The idle is pretty smooth but not perfect. I don't know what to do, or what to look for, any help would be greatly appreciated. PLEASE let me know.
Thanks

might be an oversight on your part, but you didn't mention if you changed the cap and rotor as well as the wires and plugs.

my advice would be to start with a full tuneup, and then see how it behaves. at this point it could be fuel related or ignition related, but you need to know where you're starting from with both.

Gummed up carbs are common on cars that are olmost 20 years old...

i agree. make sure you change the fuel filter, too.

If it's backfiring through the carb, I'd grab a rebuild kit and tear that puppy down. These carbs aren't terribly hard to do, but you have to make sure that you have a nice clean workspace and don't lose any of the little pieces.

Like accelerator pump inlet checkballs.

Don't ask me how I know.

Where exactly is the fuel filter located on a 1st gen (12a)?

definitely gut the catalytic converter. it is clogged.

Just above the rear axle on the drivers side.

yep that was my problem

I was gonna say the cat too. Try unbolting it and see if that makes it better. If so, time to gut it, get a new one, get RB exhaust, or get a replacement pipe.

~T.J.

The fuel filter is located on the driver's side just forward of the tank and is easily accessible if you put the car on stands or ramps. It costs very little at a local autoparts store, and is a good thing to replace, even if it isn't the primary source of your problem.

Depending on if you have e-tests or not where you live, you can gut or straight-pipe the cats, or at least the primary. If you have e-tests, take the cats off and check them, they *may* need to be replaced.

Next, either rebuild the carby, or if you don't feel confidant enough to do it, look up Rx7Carl or Sterling on this forum, they rebuild them for a reasonable fee, and from what I hear do an astounding job. The carby is a major problem centre in these cars some days... but that's only because after 20 years they're gummed to hell. Get it rebuilt and you won't have to worry about it for quite a while.

Another thing I'd check is for vacuum leaks.. Again if you don't have emissions, look for Rx7Carl and Pratch's tutorial on removing the "Rat's Nest" of vacuum tubes on the top of the engine, to simplify the system and help more easily track and eliminate vacuum leaks.

Definitely make *sure* you have the right plugs. BR8EQ or BR9EQs work well, those are NGK part numbers, from memory so I hope they're right.

Other than all that, check fuel delivery, but I'd bet my money on either a clogged cat or the gummed carb.

Welcome to the forum. These cars are a helluva lot of fun to work on. If you're interested in finding out more about the rotary engine, you can check out www.rotaryengineillustrated.com or www.howstuffworks.com (search for rotary). Feel free to post any questions you have, and don't forget about the search function which can answer many questions quickly.

Have fun with your 7

Jon

BR8EQ-14 is the stock number... Defenately get -14's as that's the reach... Too deep and you trash an apex seal...

Always get NGK's... I wouldn't use anything else...

I dunno why Autolite and Champion even make spark plugs for our cars... Complete trash.

also replace the carb 2 manifold gasket

I just put in Autolite plugs in my SE, cause thats what they had... plus i didnt have enough money for the good stuff. Is it that so terrible? The NGK's would have taken like a week to get in and I wanted to get the new plugs in for a long trip this weekend, so I had to go with what they had.

Autolites are SHITE...

Don't expect them to last very long...

frigidmonkey -

pay attention to the accelerator pump when you rebuild the carb. An inflexible AP gasket - easily the case in a car this age - can cause the stumbling and hesitation. That said, rebuilding isn't too hard if you have patience and take pics or diagram everything as you remove it.

As far as the plugs go, Autolites work fine for daily drivers. I've used Autolites, NGK and ND plugs and never noticed the difference in day-to-day driving.

autolite plugs lasted about 2 months in my car. the champion plug lasted about six months. the ngk plugs last more than a year. ngk is worth the price.

Gut the cat, you've got air restriction killing the engine's ability to breathe...:cool:

I unbolted the exhaust from the manifold and it still ran the same.
I can't find a rebuild kit locally, so I'll have to order one, in the mean time, I'll be picking up a compression tester thursday.
I WISH it had been the cat :[

well, mystery solved :[ Did the compression test today, no compression on the rear rotor :[ Guess I start saving up for gaskets , springs, and seals. Don't worry, I won't give up on her, and there is NO way I'm going to frankestein this thing

Thank GOD!
And remeber, we're always here to help.


Good Luck!
-Spencer

Hey FrigidMonkey, what part of Ohio are you in? If you're close enough I might be able to come over and help if you need any.

You know you really wanted to experience a rebuild anyway, right? :D

Good luck!

coldy, I doubt you want to make the trip, I'm about 3 hours northwest from you

If you were closer then I would help you if you need it. I really do want to do a rebuild, so I have some practice for when I put a streetport engine into my car when my currnet engine pops. But that won't be for a while anyway.