DBLBCK1

SO, after many years away from the 7, I found a 100% completly stock (the exhaust is even a Mazda part) 1982 GS in Minnesota (I am in WPB, FL). So, $3K later, and $700 in shipping, I have my car. I bought it from the original owner, 94K, with the original window sticker, and the dealer warranty book with every service ever performed. Never saw a winter in 25 years, no rust, no accidents, just some holes in the seats, and some peeling paint on the bumpers.
I want to keep this car 100% stock, and anything I do...springs, shocks...etc, has to be reversable. This is my 4th RX7 since 1991. 1st was an 1982 GS, then a 1986 GXL, a 1988 10th Anniversary Turbo....now back to the 1982 GS.

Now all WAS well, no problems, no issues, just enjoying driving this survivor. Yesterday on the way into work, nothing out of the ordinary...until after cruising, without issue, on the freeway (like every morning)...I get to the bottom of the off ramp, and boom stalled. It restarts, but will not hold an idle...so I limp it into the parking lot, and bump the idle up to keep it running. Running rough. Not sure what happened, it runs and starts now without issue, but idles rough (not bucking, just a lot of vibration, and shaking) back at 750-800rpm. When driving, it bucks (lightly) up to 4K, and slightly more pronounced on decelleration. It sounds different too, more harsh...not as smooth as it did over the last month.

Any ideas? Like I said...no mods at all on this car, it is all just as Mazda delivered it.

Any help would be greatly apprecitated!

Andrew

85 FB

I'm wanting to guess ignition problem. Possibly a coil.

DBLBCK1

That makes sense, thanks. Is there a way to diagnose, or should I just swap them out for a pair of new ones?

mikewoodkozar

I would check to see if you are getting proper spark at the plugs too, when was the last time the fuel filter/pump was changed?

DBLBCK1

Not sure on the fuel filter and pump. I have the new filter in the car....oddly enough I picked that up earlier in the week to change today.

mikewoodkozar

Funny thing is that even if the car has been babied and original, anything can and will happen with our "nearly" historic cars

DBLBCK1

True...but for all of it, when they are running right...there is nothing like it. I am going after a pair of new coils...$30 each at Napa.

mikewoodkozar

If the budget allows it i would buy the MSD blaster 2 coils

DBLBCK1

OK...ended up with Accel Super Stock Coils from Advance Auto. One Chrome, One Yellow (they only had one of each). $32 for the Yellow, $33 for the Chrome.

mikewoodkozar

yeah, keep us posted and good luck!

DBLBCK1

Will do....I hope these do the trick.

Directfreak

iTrader: (2)

If not the ignition, could be a side seal. Compression check FTW.

Vashner

I'll insert my usual suspect. Anti Afterburn Valve or hose leading to it...

bliffle

Shutter valve, perhaps?

mikewoodkozar

Aha, that pesky shutter valve, could be

boyee

iTrader: (3)

i had the same symptoms you described. it turned out to be an internal leak from my air control valve (ACV). check for any vacuum leaks too

DBLBCK1

Coils in, fuel filter changed. Starts right up...cold....and hot...idles at 750. BUT no change. Revs up fine (sounds rough though)...with a slight stutter off idle, then dips...like it is going to stall, and goes back to 750. Exhaust sounds like a helicopter. Not humming, sounds like a chainsaw.

DBLBCK1

Waiting for first light to check the ACV and Shutter (what is the best way to check these two?) Another question, if it was a vacuum leak somewhere, how could it idle at 750-800? I thought that a vacuum leak would cause an incorrectable high idle?

mazdaverx713b

iTrader: (91)

a vaccume leak can cause an idle problem for sure. i would then check the anti afterburn hose. it runs from the anti afterburn valve on the carb to the intake manifold. this is a hose that commonly fails causing various stalling and running problems.

DBLBCK1

Idle is solid.....just loud with abnormal vibration. Sounds like a chainsaw coming out of the carb when I take the lid off.
Is there anyplace I can post a video of it so that everybody can get a better idea?

rearviewmirror

Put it on youtube and post the link.

trochoid

iTrader: (6)

As Directfreack said, do a compression test, From your details, it sounds like the classic sudden side/apex seal failure. It's odd how it seems to happen but coming off highway onto an offramp seems to be a common form of failure with no rhyme or reason behind it.

DBLBCK1

It starts right up, hot or cold (with the choke). Hot, less than a half crank, and no smoke.....when hot....light blue when cold....for about the first 3 seconds, then nothing. I would say the compression is fine....when my 86 lost compression, it would barely run...and forget about starting it hot.
Going to upload a view vids to youtube and post the links...a cold start, and then a hot start.

trochoid

iTrader: (6)

When you shoot the vid, make sure you show the vibration. Also check all 4 plugs for good strong spark and pull each plug to check for color/fouling.

DBLBCK1

It has the 14s in it (and they look pretty new)...I will pull them after I post the vids. You think that bad plugs could cause this issue?