RX7 cutting and misfiring
 

I just bought a 93 rx7 and the car cuts out and misfires when i quickly accelerate and it reaches around 4000 rpm.
The previous owner says that the car has had this problem before and he took it to guy who cleaned the throttle position sensor and the car ran fine again.

Initially i tought that it couldnt be so i took the car for a diagnosis and errors 51 and 54 came up (air pump relay and fuel pump relay short or open) can someone help me on this?

I already changed the fuel pump and nothing changed, the curious thing is that if i accelerated slowly the rev passes the 4000 and can sometimes reach the 9000 rpm in neutral but if i'm driving and i use the same procedure it only goes up to 6000rpm.

Is it an auto or manual transmission? Do you have a boost gauge? I recommend a boost gauge regardless of this issue.

Both the fuel pump speed relay and air pump relay can cause driveability problems. I suggest you follow the Factory Service Manual (downloadable from links listed in the 3rd Gen thread at the top of this forum) for both trouble codes.

Dave

its manual, i read somewhere that the TPS can also cause this any hints about its location?

Sounds like you're in limp mode. If its cutting out under load, but if you feather the throttle you can get it going ok.

So, one of the codes you have might be putting it into limp. Do a quick test, disconnect the battery, press on the brake pedal, wait 30 seconds to "reset" the ecu. Reconnect the battery and drive it around. If your symptoms go away, you need to fix whatever putting it into limp, ie error codes.

interesting thread. Let us know if you figure the problem out. My old gf use to miss around 4000 rpm, but it kept going.

The TPS is right behind the throttle body facing the firewall.

However, since the codes you have are both documented in the FSM to cause driveability problems, I would worry about those before the TPS. Do you have damaged wiring anywhere? Is one of your front wheels rubbing through the wheelwell liner?

Dave

i checked the wheels and some wires were cut , i replaced them but i still have the same problem, i spoke to a mechanic and he told me that it might have something to do with alternator , is it possible?

now the car is cutting below 4000 rpm and seems to be getting worse, i replaced the spark plugs but the change had no effect. how can i sort out those 2 error codes? must i change the relays?

You can test the relays before replacing them.

I recommend that you follow the FSM procedures for these trouble codes. This will detect shorts in the wiring harness, faulty components, etc.

You can download the Factory Service Manual by following the links in this forum. The ECU code troubleshooting is in Section F.

Dave

i just checked and found out that there are some vacuum hoses disconected, can this be the cause?