Hello, I been having problems recently on my 83 RX7. Earlier in the spring, I started my car and it start up fine, I got out of the car to let it warm up. When it was warming up it bogged and died out. Ever since then the car hasn't been starting at all.

I need help with diagnosing what could be the problem. I changed the spark plugs, wires, and fuel filter, but all these changes still never made it start. I used carb cleaner and it started but dies at 2k rpm. I'm running out of options.

Here is a video link of what the car does. I used carb cleaner (only way it would start), but dies shortly after.

 

Dead fuel pump.

 

Thanks for the help. I'll replace it and give it a try.

 

Just replacing parts without doing the homework can get expensive real quick. I would make
sure the pump is flowing fuel to the carb at a decent rate. Take the hose off at the carb and
see how fast it fills 1/2 gallon. It should do it pretty quickly, like in about 3 seconds or so for a
stock pump. If it fails that test, then yeah maybe you need a new pump. But then you need to
make sure its not a blockage in a line or the pickup in the tank. A new pump won't fix that!

 

Ditto on what Tim said, except that it takes the stock fuel pump 60 seconds to deliver 1/2 gallon of fuel, not 3. The fuel pressure at the carb should be about 3.5 psi.

You should check these specs first, if they aren't in spec, it could be the pump but it could also be an obstruction, most likely related to a dirty fuel supply or tank. Since the fuel pumps rarely go bad, it would most likely be dirt in the tank or fuel plumbing. To verify, you can disconnect the fuel line at the fuel pump to see if gas is flowing at that point, or any place else along the line back to the tank.

On the other hand, if you're getting proper fuel to the carb, the obstruction might be in the carb inlet filters or maybe a stuck float valve. If so, there won't be much fuel in one or both float bowls.

Verify that there is fuel in the float bowls using the inspection windows on the side of the carb. The fuel should be halfway up the window. If not, and you're getting fuel to the carb, you will need to take the carb apart and see what the problem is, which is also a good time to clean things up and install a rebuild kit.

 

Yes, test the pump to see if it's flowing. Even if it's weak, it should flow enough to start and idle the engine. Also, there is a fuel pump fuse that could be blown. Do you hear the pump buzzing when the key is on but the engine isn't started?

 

Guessing its an original pump, its probably due. I seem to always have issues with the factory 12A fuel pumps.....

 

I've been through three or four of them myself over the years. At least they're cheap to replace and easy to get at.

 

Strange, in 12 years of driving RX-7s, I've never had an original stock fuel pump go bad. Lots of other fuel issues, some I've tried to fix with a new fuel pump, only to have a $100 investment sit on the shelf and then discover it was something simple, like clogged prefilters in the carb.

Since a proper diagnosis is much less work than replacing a fuel pump, it seems like the cheap and easy thing to do would be to figure out what's wrong before fixing it.

 

Thanks for all the feedback. I know what you mean by replacing part will add up. I replaced some of the basic parts, just replaced the ignition coils and didn't do it. But I'll check the fuel pump and other areas you all mentioned.

 

As far as the pump. I haven't notice it making any noise when turning the car on before starting it.

 

There's also a fuel pump relay just under the dash by the gas peddle that can go bad. You can jumper a couple of the plug wires to test.

 

Because of the aforementioned relay, you won't hear the fuel pump before starting because that silly relay only turns the fuel pump on while starting or when the engine is running.

SO basically, unhook the fuel hose from the carb inlet, have a friend crank the engine for you and see if anything comes out. If i'm right, nothing will lol.

Of course the fuel pump just quitting like that points to a cruddy fuel tank or clogged fuel fliter possibly.

 

When did that relay get put in? Both my '79 and '81 activate the fuel pump when the key is in the on position.

 

84-85 and it's controlled by the trailing ignitor.

All rotorheads on this forum should know this so they can help others.

If the engine isn't cranking or if the ignitor stops working, so does your fuel pump.

One of the first things I deal with on an 84-85 chassis is to pull the connector from the relay under the dash and hook up a jumper wire. Makes life a lot easier during the get 'er running phase.

As for the OP and his 83, I'm thinking his fuel pump just sorta died so it's time to throw another one in there. It's original so you might as well.

 

[QUOTE=MosesX605;11755724]When did that relay get put in? Both my '79 and '81 activate the fuel pump when the key is in the on position.[/QUOTE

Don't know when the relay got put in, I'm the third owner, but I'll check that out too. Thanks for all the help, I appreciate it.

 

Nice! Here I was thinking that they all had it from like 81-85. My cars are usually 84-85 models, so I guess I was just used to it.

Either way, to the OP it certainly seems to me a glaring sign of a lack of fuel, for what ever reason.