Breaker

Does any one know why my motor hesitates @ 3800rpm? I have an '87 RX-7 N/A, w/ 188k on it. A friend and I raced this past weekend and he was able to beat me with ease. He's was driving a Corsica, needless to say that he took me MAZDA badge after the race. I need to beat him next time to get it back. Sure, I can go out and buy one, but the pride just isn't there if I do it that way. PLEASE SOMEONE HELP ME...

1987RX7guy

iTrader: (3)

Most RX-7s have this hesitation. It can be caused by many things so it may be hard to get rid of. Solution is to downshift and keep it above 4k and shift at 6500 or 7k. Whats up with the tag takin lol he actually took the Mazda tag????

SonicRaT

iTrader: (6)

Usually two reasons for this 1) dirty injectors 2) bad engine grounds. Either run some injector cleaner through there and see if that helps, or add some grounds to your engine. Search and you'll find more information that you could ever hope to know.

Josepi

Or the grounds by the ECU since the ECU needs proper grounding to send the pulsed ground to the injectors. If the ecu isn't getting a good ground, neither will the injectors.

SonicRaT

iTrader: (6)

Doh! You got me Josepi! How about grounding the pressure sensor!? That's rumored to help too!

Breaker

Well, in my town we don't race for money anymore. But we race for badges. The badges are like a trophy and sense of pride goes with it. So far I have aquired a Metro badge. Well the guy wouldn't stop running his mouth so we met up at a light and he was piped the hell out of his car at me, so I piped back and well I took his badge.


So, I need to add more grounds to the motor and ECU, dump a bottle of injector cleaner into the car also. Got it! Thanks again Guys!

SonicRaT

iTrader: (6)

Yeah, it'd be a good idea to read the FAQ that's sticky'd at the top of the page, that has some good information on it as well, especially since you seem to be new to the forum, that's always good reading!

SOIA

Check the connector at the AFM (air flow meter) get a good electronics cleaner and spray it down also try spraying inside the AFM. It solved my problem, hope it'll work for you.

13bpower

I'm supprised no one has mentioned that it might be the normal 6th ports opening dip that all the 6 port rotaries have. If he doesn't have much rotary knowledge he might not know this. Although the injector cleaning and grounding will probably help, there will always be some hesitation there.

Icemark

There should not be any hesitation there. It should be like someone turning on a small turbo. Power flow should steadily increase, and then boost up more.

If there is any hesitation the car is not running correctly, and more than likely the 5th/6th ports are not opening correctly if everything else has been checked.

Breaker

Yes, I'm new and I really don't know that much about rotary engines, however, in my defense, I'm learning as much as I can about them.

Well, I did some exploring on the site and found the how-to's on cleaning the 5th and 6th ports, so that is this weekends job.

Sorry guys, I bought a RX-7 that was beat on by 22 previous owners, and I'm doing everything I can to keep it from going to the grave.

I'll try the electrical side of it also.

I wish that it did feel like a small turbo boosting up, that way I can leave my hood down.

]]]Question: Does anyone know how much boost the stock motor can handle? Also, does anyone know the the rear end gears are?[[[

ilike2eatricers

if this was an electrical or grounding problem would a product like deoxIT D5 help any?

this product is supposed to improve conduction, deoxidize, and protect and seal connection.

By the I heard about this product from a person who uses this on computer wires very avidly.

Thanks in advance.

SonicRaT

iTrader: (6)

What are you worrying about boost for on an NA? Anywho, it depends on the model you have, assuming it's a 5 speed and not a GTUs, you should have a 4.1 rear gear. About the contact cleanre/deoxodizer mentioned above, it's not going to do much if the weak pathetic ground wires mazda used originally are just too bad anyway, this is why we suggest running new lines, which would be a great canidate for what you mentioned. It's 99% of the time either grounds or dirty injectors.

ilike2eatricers

thanks sonicrat just wanted to make sure

Breaker

I have a bottle of DeOXit from one of the Xerox guys that I know, so I'll use that, I'll also, be replacing the stock grounds with a few beefed up ones that a HONDA (Hold On Not Done Accelerating) owner just gave me. I think I have three still. About how many am I going to need? I'll also be dumping injector cleaner into her tonight and this weekend I'm cleaning the 5th and 6th ports. Anything else that I might need to do?

1987RX7guy

iTrader: (3)

well you should get a gasket for the manifolds that you are taking off. Buy tons of carb cleaner for the ports and sleeves.

Breaker

yeah, I always replace the gaskets, it like second nature to me.