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RX-7 has good compression but is running on one rotor
Hello all, I have an S5 RX-7 Convertible NA with 157k miles thats been giving me trouble lately. Right now it runs on only one rotor and can't get up hills, and has an idle that bounces up and down between 1k and 2k rpms. I'm experiencing jerking when coasting/moving at low RPMs, no power, brand new plugs immediately fouling, one my header pipes is glowing red from richness and it has the infamous one-rotor chainsaw sound.
I've replaced the plugs, wires, fuel pump and filter, I'm in the process of replacing all vacuum lines and intake gaskets, set the TPS, restabbed the CAS, replaced the O2 sensor (though i think the wire is grounding out somewhere) and I am trying to get the idle to go down so I can time it. It also has a full RB exhaust because my cats were starting to clog after the symptoms appeared. I have CEL codes 12, 17, 18, and 30.
The motor had even compression last time I checked it when the symptoms started (about 90-95 psi per pulse on a standard tester with the schrader valve removed) I'm not burning any coolant or too much oil and my exhaust looks clean. Im honestly stumped on what could be causing my issues, and they only started after seafoaming the tank to clean the injectors.
I'd rather not rebuild it yet since it has good compression and fires right up when cold even on one rotor, but if anyone could help point me in the right direction I'd greatly appreciate it.
which one is not firing, front or rear? did you check for spark on the side that's not firing?
it's a very good idea to check for potential vacuum leaks. so good thinking on that.
Originally Posted by nat.m_m_
... and they only started after seafoaming the tank to clean the injectors.
you may need to have them professionally cleaned (WitchHunter, Marren, RC Engineering, etc.). maybe try swapping the injectors - front to rear and vice versa, and see if the dead rotor moves with it.
here's a link to getting a copy of your FSM: Foxed.ca
which one is not firing, front or rear? did you check for spark on the side that's not firing?
it's a very good idea to check for potential vacuum leaks. so good thinking on that.
you may need to have them professionally cleaned (WitchHunter, Marren, RC Engineering, etc.). maybe try swapping the injectors - front to rear and vice versa, and see if the dead rotor moves with it.
here's a link to getting a copy of your FSM: Foxed.ca
I'm inclined to believe my rear rotor isn't firing but I'm not sure. The rear rotor half of the header is the only one that glows while idling and I haven't checked the spark yet. Is it simple as just pulling the plugs while it's running?
no. please don't try to pull the plug while the car is running. very dangerous!
since you replaced the wires and the plugs, i would suggest you take a look at the coil and perform troubleshooting procedures according to the FSM. to be honest, i don't expect you to find the coil to be the problem, but assume nothing.
if you have pinpointed the beginning of your issue to coincide with your Seafoam use, then you might have simply fouled up the injector with something that got dislodged or partially dissolved. i suspect the injector to that rotor is clogged or something and you're running lean at idle.
do you happen to remember what the gas looked like when you changed the fuel filter?
Last edited by diabolical1; Apr 9, 2024 at 03:54 PM.
no. please don't try to pull the plug while the car is running. very dangerous!
since you replaced the wires and the plugs, i would suggest you take a look at the coil and perform troubleshooting procedures according to the FSM. to be honest, i don't expect you to find the coil to be the problem, but assume nothing.
if you have pinpointed the beginning of your issue to coincide with your Seafoam use, then you might have simply fouled up the injector with something that got dislodged or partially dissolved. i suspect the injector to that rotor is clogged or something and you're running lean at idle.
do you happen to remember what the gas looked like when you changed the fuel filter?
The gas looked clean when I did the filter, although it does seem possible I could've clogged an injector. I already pulled them off the motor to rebuild them when the parts come it. Thanks for the warning about pulling the spark wires off haha, I'm still pretty green when it comes to diagnosing engine problems.
Do you know how many miles or years are on the spark plugs? If you haven't changed them recently, that might be a cheap and easy thing to try. Sometimes spark plugs can get fouled, which is difficult to see by looking at them, and they won't make a good spark.
