Rx7forfun

I have a 1989 rx7 non-turbo with 123,000 miles on it. Just bought it, I had a first generation and sold it and thought I would try a second generation. I bought it in not running condition. I went online and found the fuel unloding trick. Did it and put in new plugs, she fired right up. Car runs ok on the freeway but everytime I start it up it only runs on half the motor, then after about 30 seconds at 2500 rpms the second rotor fires and it ok. It has a surgine idle about 12 to 16 hundred rpms. So far I put in new NGk plugs and wires, adjusted the tps according to the book. put in a new oxygen sensor, changed the fuel filter, drove it on the freeway for 200 miles. Seems a little better at idling, but still has the problem of starting on one half of the motor. I checked for air leaks but found none, sprayed carb cleaner in air intake and still no change. I checked for computer codes and it has none. My friend who does electronic repairs, resodiered the computer boards. Car still does the same thing and it is really hard to start like this when it is hot. Cold starts seem to be no problem, but still starts on half the engine. You can hear it fire on all plugs after 30 seconds of start up. Any help would be greatly appreciated, I'm going crazy. Ps. the car will rev to 8,000 rpms and doesn't smoke.

pp13bnos

iTrader: (1)

Injectors could be the problem....but i doubt it. Motor probably has had alot of hard miles on it. Causing low compresion on one of the rotors. I could be wrong though. Good luck, CJ

ka8legend

I know it can run just off the leading coils, but one rotor running? Have you try unplugging the leading wires from each of the rotor to see which one is not firing? The 30sec thing is prolly the warm-up cylce to pre-heat your cats. You can tap on the gas pedal the next time you do a cold start to see if it's still "running on 1 rotor". BTW how's your idle once the car is fully warmed up?

Juan

iTrader: (28)

does it sound like a beat up lawnmower when it does that? My car starts up weird sometimes when its cold in the morning. Kind of sounds like a messed up lawnmower and it backfires if I rev the engine. This goes away after a minute and idles normal. I think Its because the car floods and even with my fuel cut switch it still does it randomly.

akageals

I'd look at 4 things in this order:

1) If you can do it yourself (ie. free) check the compression just to be sure.

2) It could be a badly leaking injector flooding that one side of the motor.

3) Vac. leak (but you already did this).

4) Use a timing light to see if the plugs are firing when it is doing this on startup.

If indeed there are no vac. leaks, i'd guess injectors (had a similar problem when one of mine got clogged only it did'nt clear up...only ran on one rotor until I changed the injector).

Todd

RotaryMotorDisorter

Your not alone, my 12 used to do this. I have no clue exactly why it ran on one rotor sometimes. I went on a long trip and ran it about 75 mph or more the whole way and back. I havnt had the problem since, but i feel your pain and know what its like to have half the HP!

proudrx7driver

what was the trick to start the car up better? and how does this work? is it worth it?

rx_7_driver

how can u tell u r only running on one rotor (becides the lack of power)(i mean at start up r idle)

-Shawn

rotaryrules

I had the same problem . Specially hard to start when car is warm. Do a search on CRC copper weld and follow the instructions on flushing out your radiator and using this stuff. Large problem with high mile rotarys is the coolant seals go bad allowing water to enter the system, which makes it hard to start. I flushed out my radiator according to the posts on here regarding CRC and never had the startup problem again. DO NOT FOLLOW INSTRUCTIONS ON BOTTLE OF CRC> IT DOES NOT WORK. You must flush out your radiator about 7 times with purple power degreaser and make sure all coolant is out of the system before putting CRC in. You really have nothing to lose.-------late Ren

88 SE

Sounds like injectors to me. Mine had the same problem of running sometimes on only 1 rotor. Turns out it was bad injectors due to the previous owners putting incorrect resistance injectors on the car, causing them to die in a short time.

I can tell you for sure whats wrong if you can answer me this.. what color were the old plugs? was one a different color than the other?


IF the injectors are fine, then surging idle will be caused by a vacuum leak or incorrectly adjusted TPS, simple as that.