It seemed mighty odd that after waxing my '86 RX-7 that a long-time engine problem magically went away. So I thought I'd run this past other RX-7 enthusiasts.

For over a year, any time I would accelerate up to 4000 RPM, the engine would begin to temporarily cut-out (bucking, hesitating) until I got beyond 4300 RPM and then it would smooth out completely. This was very consistent no matter what gear, provided I was actively increasing pressure on the accelerator. It progressively worsened over time and was a mystery to me and the shop (they couldn't figure it out -- but they were not Mazda gurus).

Yesterday, before waxing it, I decided to do a quick cleaning of the engine well to get out the dust and smudges on the inner body. I put in a light spray of orange-based engine degreaser (like 1/3 of the can), followed by a quick and conservative rinse with the hose. Finished the exterior with good waxing and closed up the garage for the night.

Today, I was surprised and thrilled to find that I was accelerating through 4000 RPM with NONE of the aforementioned sputtering. Certainly, the wax job didn't do this. Could the engine cleaning fix something? Maybe it had the affect of lubricating some stuck linkage critical when you get into mid-RPM range? Has anyone experienced this ~4000 RPM acceleration trouble?

Car is now running great. It looks and runs 10 years younger today. It's a fun, kick-*** little pod racer!

(BTW, what does an immaculate '86 non-turbo with 121,000 miles and perfect interior/exterior go for these days? My step father bought it new in '86 and babied it. I inherited it when he passed away. It has spent a good deal of time in the garage with periodic driving just to keep it in shape. 100% original everything -- no mods other than a sun shade on the rear hatch.)

 

When you were degreasing the engine it may be possible that you cleaned off the 6th port actuating rods, allowing them to open freely when accelerating. ( 5th and 6th ports open at around 3800 rpm, and can commonly get stuck, giving you a sort of "stumble" around there) And about the value of your car...I say that you may be able to get $3000 for it.

 

He he.
Welcome to our world little grass hopper. You shall find that if your car doesn't like the way it looks, or the people you take out in it it will run like crap when evr it feels like it. But in your case it sounds like you have the throtle plates like the secondaries stuck alittle at the pivot and the degreaser fixed the problem. Happy playing.
regards,
Charles

 

I should try that! My 6 ports don't work.

 

$1.5-3k depending on color, options and such.

 

Sounds to me like your TPS was stuck and a little bit of degreaser landed on it and freed it up.

 

Oh yea, I wouldn't take less than $3000 for it, never underestimate the value of your car, especially one in such good condition as yours

 

come and wax my car maybe my dent will disappear

 

Thanks, all, for the warm welcome and excellent feedback!

Your suggestions about what might have cleared up this problem sounds quite reasonable. Any tips on making sure the port actuating rods (and related linkage) is thoroughly cleaned and lubed so this doesn't bite me again (at least for a while)? (e.g., recommend any types of solvents, lubricants, techniques?)

Curious. 7Dreams suggested it might be the throttle position sensor. Is the TPS mechanical on these cars?

(In my teen years in the late 70's, I used to work on my cars every weekend -- now I just look under the hood of anything older than '84 and feign intimate knowledge).

Also, $3K is about what I figured the car might be worth. Appreciate the blind appraisals! Are pictures allowed outside of the gallery area in these forums?

 

Yes, you can post pictures. I personally disagree that the degreaser did anything to the TPS, but I suppose that anythings possible. The TPS is mechanical I guess, it reads off your throttle linkage on the TB.

 

probably unstuck something in the engine bay that was either stuck together, blocked off, or plugged up..

 

I was thinking this, too.