Hello,

94 Mazda Rx7
120,000 miles
3000 miles on Engine rebuild
5 year ownership

I have a 94 Mazda Rx-7 which I brought to California last year...everything was running fine until I brought it to the smog shop. They said my Car was running too rich, and my PCV hose was too long.

So I went ahead and took off the UIM, fixed the problems, but kept running into more Problems. Broke the Alternator B+ Terminal Post during this repair, than replaced it. Slave Cylinder and Master blew out during this and I replaced it. Put everything backed together, started the Car and now it will only run for 10 seconds than die...(maybe I have shorted out some wires after trying to run car with broken B+ Terminal Post?)

So I checked fuel pressure, was only getting 21psi for my Maximum Pressure. I went ahead and Replaced the Fuel Pump, also did a FP re-wire job in the rear. Now it's getting 40psi with the Fuel Pump Jumped. Fuel Lines do Hold pressure...

Fuel Filter replace 3 years ago.
Replaced EGI main fuse, Fuel Pump Relay and Speed.
IACV 12.3 ohms
Battery is functional
couldn't find any major vacuum leaks
Tried doing de-flood procedures
New Manifold Pressure Sensor
New Fuel Injectors ( Installed and working prior to bringing it to Smog Shop )
New Spark Plug Wires and Plugs

I also noticed there wasn't any power getting from Main Fuse to Idle Air Control connector from harness, so I jumped the connector to a 12v switch. (The other solenoids are getting Voltage.) I also went ahead and replaced the ECU.

I have taken the UIM off and put it back together 3 times within a year now...and Car still starts for 10 seconds than dies. RPM gauge also does not rise when I hit the throttle. Any Ideas?

**Everything is pretty much Stock since I am trying to pass smog**

 

Does it hold the fuel pressure while starting and running?

Have you checked your TPS?

Any codes in the ECU?

 

Wow, that's a tricky one.

When you broke the main alternator terminal, I assume the battery was hooked up at the time?

If you start it, can you hold down the gas some to keep it running?

The tach doesn't work at all?

Dale

 

Yeah the battery was hooked up, and the tach is working just fine. But I did notice afterwards I tried to get the battery Voltage with my Multimeter, the Lead Wires get super hot and burn up.

Theres just No response to the motor when I hit the gas, but it does run for a second longer if I pump the gas. Accelerator Cable is Adjusted.

 

I just got everything back together, but on a Fresh start I would get 10 seconds. The second time around it will only run for 3 seconds and less...seems to be flooded so I can’t get the pressure while running. I would have to a wait few days to try again and get footage of the pressure while running on a fresh start.

I looked at the TPS but still have yet to do the procedure for proper voltage.

I have not checked the ECU for any error codes yet.

 

When you broke the alternator B+ post, did you get a big spark/pop from it shorting out?

You may also need to look back over the work you've done. Something that was touched between then and now is the culprit. May want to take a number of pictures and post them up.

Dale

 

No sparks, the post was still slightly attached and I also brought the Alternator to test at O’rielly’s and they said it Failed. Got a new one from Atkins Rotary.

I thoroughly went over my work 3x, maybe I will need to do more testing.

I will get to work on it Sunday, I will take some pics/video, do the TPS test and check ecu codes...we’ll see from there.

 

Once you take care of the flood and can verify if the pump loses pressure after a few seconds, that pressure loss would be due to "fuel pump resistor". There are plenty of threads on that part if you search it, but in a nutshell when it's bad you will get pressure long enough to start the engine and a couple seconds after, then it just shuts the pump off.

 

You can jumper the F/P and GND terminals in the diagnostic box to run the fuel pump full speed all the time. Might be worth doing for troubleshooting.

Dale

 

I already bypassed the FP resistor and jumped it from the Resistor connector.

 

I already hooked my FP directly to the battery to get the 12V all the time, but I will try turning car on with FP and Grnd Jumpered.

 

I also purchased a new throttle body and just bolted the TPS sensor on there without knowing that it’s Position would affect the voltage ...Could this be main Culprit on why my Car dies???

 

Exact same symptoms I am having...can’t wait until Sunday!

 

I just fixed my car. Tps was one of the things i changed.
when i moved it out of position car ran horrible and also died which also caused my leading plugs to foul which then made things even worse
Cant go wrong with fresh plugs

 

I’m just happy I know where exactly the problem is and don’t have to Waste Money elsewhere!!!

But it was a Good way for me to learn about Rotaries and how the system works!

 

Tested out the TPS

the Narrow Range was at .04v closed.
It should be from 0.75-1.25V at closed position.

The Full Range was at .03V closed
It should be from 0.1-0.7V at Closed position.

And its not affecting the Voltage when I move to Fully Open Position.

From the looks of it on this forum, so many other FD owners are looking for this discontinued and pricey part...I waited 7 months to find an OEM Catalytic Converter, why not a TPS?? Or another that can replace OEM...hope it doesn’t take long until I can find a replacement!

 

Did you only test it closed? Opened?
Did you adjust it so it goes within range?

I approximated mine cold and then when the car got to operating temp retested and adjusted

 

I tested it Cold, figure it would run for only 10 seconds so why bother trying to warm it up?

Yeah I tried adjusting, testing it Opened and Closed, no difference to the values of the voltage.

 

I just purchased a spare from Japan but don’t recognize this number. N3A1 1X22E Does anyone know if this one is for Japan Only?

 

Japanese TPS's are identical. The N3A1 shows it's an FD part, the other numbers aren't a part number, they may be a lot or job number from the factory.

Dale

 

Found a spare TB assembly off of ebay, didn’t get a good look at the tps so I got it anyways...but heres what I got when I got home today.


Luckily I found another spare one from Japan that’s coming tomorrow, will be sending this one back. Still looking for a New TPS.

 

Did uhh did you try it

 

Have you checked the MAP sensor line?
My car idled if at all like crap when I connected to the wrong place.. it was just a nub not the actual vacuum/boost connection.

After I found my stupid mistake it idled like a champ.

 

Didn’t bother, it was broken at the connector and the chip was broken.

 

Yeah I got a new one but the old one made it run a few seconds longer. Lines are ok...I’m 100% sure its the tps...