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-   -   Just bought my 1st rx-7, but it seems whimpy...please help! (https://www.mazdaforum.com/forum/mazda-rx-7-33/just-bought-my-1st-rx-7-but-seems-whimpy-please-help-17443/)

booksbaker 02-02-2009 12:41 PM

Just bought my 1st rx-7, but it seems whimpy...please help!
 
Here's some background info:

I just recently bought my first RX-7. It is a 1987 FC (13B motor). It seems to be an awesome car, but I bought one with an automatic transmission (for my wife to drive). I bought the car because I had driven one very similar to it about 10 years ago...and I was blown away! That one had a manual transmission though. I loved the torque it had and how you could really wind it up to some high RPM's.

My problem is:
With this new purchase of mine, I have found that I can't 'punch' the gas in this car like I could with the manual transmission one. It's like the car has no 'get up and go'. If I'm on the interstate and I want to pass someone, I will try to accelerate by pressing down on the gas. The car will downshift, but then if I keep the gas down, the engine just seems to 'bog' down. I can let off the gas a little bit and the car will accelerate just fine. There's a point
I hit where the car doesn't acknowledge that I'm giving it gas. This happens in every gear except 1st (only when I manually put it into 1st gear).

I hope I'm making sense here.
Is this standard for an RX-7 with an automatic transmission? The car only has about 115,000 miles on it. Like I said, it's been well taken care of.
Please help..... I really like this car, but if I can't resolve this, I might just have to resell it.
Thanks!

hixx 02-02-2009 05:57 PM

There are a lot of possibilities. I would replace the fuel filter and throw a bottle of Techron in the gas tank. Check the sparkplugs and make sure they are the correct ones as they are special and should be NGK. The converters have a tendency to partially clog and can be visually inspected by disconnecting one end. The intake to airfilter box has to be perfectly sealed since it uses a flap type airflow meter. The coils are probably 22 years old so i would chunk them unless your sure they have been replaced. An ECU from a manual trans car will work in an automatic so it is in the realm of possibilities that it has been replaced with the wrong one though i doubt it.
Those are a few basic things to check,however there are lots of possibilities. TPS/fuel pump/boost sensor/etc/etc.

booksbaker 02-02-2009 09:35 PM

Wow thanks!
 
I will definitely check out all of those things you suggested. I'll let you know which one of them was the culprit.
Thanks again!

wsoape281 02-03-2009 02:14 AM

if nothing works, you just need to face that it is an old automatic. in the houston rx7 club, we had a dyno day and a naturally aspirated automatic fc pulled 75 hp on the dyno. old fc autos tend to just be dogs. get a manual to get some power. just give your wife the auto and buy yourself another one.

Mazmart Trini 02-05-2009 08:48 AM

The coils are the strongest parts on FC RX7s. Auto NA FCs are not known for their speed. If your wife knows, or is willing to learn to drive a 5-speed, a swap is very easy.

wsoape281 02-05-2009 01:17 PM

yeah, some of the FD guys are actually swapping their stock FD coils for stock FC coils as an upgrade.

hixx 02-05-2009 07:43 PM

Coils charge and discharge constantly,they heat up and cool down. Over time instead of putting out say 20k volts they will slowly start putting out less voltage. The spark gets weaker and more unburned gas hits the converters and slowly degrades them. A coil that throws spark and does not leave you on the side of the road does not mean it is just peachy. On single coil vehicles the coil should be replaced every 100k miles or so. You will not always see direct effects of a degrading coil as far as performance but the damage an aged coil can do can be very expensive.

Mazmart Trini 02-06-2009 02:36 PM


Originally Posted by hixx (Post 86336)
Coils charge and discharge constantly,they heat up and cool down. Over time instead of putting out say 20k volts they will slowly start putting out less voltage. The spark gets weaker and more unburned gas hits the converters and slowly degrades them. A coil that throws spark and does not leave you on the side of the road does not mean it is just peachy. On single coil vehicles the coil should be replaced every 100k miles or so. You will not always see direct effects of a degrading coil as far as performance but the damage an aged coil can do can be very expensive.

The FC coils are touted as being some of the best in the industry period. There are some people making some good horsepower on their original coils.

hixx 02-06-2009 08:29 PM

I never said they were'nt good coils. They are still coils bound to the same rules of the universe as all coils. They wear out and put out less spark. If they don't put out their maximum voltage they were designed to it causes problems including carbon accumulation. Ever see a rotary lockup? I've seen tons lockup from excessive carbon.Theres even a special tool to unlock the engine from carbon accumulation.


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