Dear smart people of RX-7 club,


My car (for those that don't know, its an 88 RX-7 Turbo) has a toggle switch that is hooked up to the fuel pump. Such a switch makes it easy to clear out a flooded engine, something rotary motors are notorious for. I have always turned my car off by flipping the switch and letting the motor die on its own.

Normally, it only takes a few seconds for the engine to run out of fuel and die. But lately, the engine has taken 10-15 seconds to die. I can even rev the motor while this is happening, and the engine still runs. My car is also noticably harder to start now, and I'm thinking that these two problems are connected.

Does anybody have any ideas on what the problem is? I think I know what it is, but I'd like some unsaturated input.

Thanks, Brian Doty

 

maybe its running really rich so there is excess gas in there to burn up ?

another guess is that all the fuel in the lines after the pump is still going thru the injectors even after the pump is off

i really dont know im just guessing so dont take my answers seriously , im having some problems of my own with my rx7, so i wish you the best of luck fellow s4 owner mines an na tho

 

are you running premix? Its not the best idea to shut her down like that, its good if your going to service the fuel system because it will eliminate most of the residual fuel pressure, but whats the point of killin the fuel just to shut her off?

 

Yes I am, not that it matters. And there is nothing wrong with shutting a car off like that, especially an RX-7. It gets most all of the fuel out of the combustion chamber.

 

Anybody else have any ideas?

 

I take this as an invitation to guess...

What would happen if your fuel pressure regulator failed open, so that you have very low fuel line pressure?

If that could happen (I don't know), then it would be possible that the lower system pressure would feed fuel through the injectors at a much slower rate, and cause the car to run longer before shutting down. Then on the re-start, it would take longer to re-pressurize your system, causing your starting time to be longer.

If the above were true, it seems like your performance would be noticeably degraded.

Or, maybe the relay for the pump is bad, such that the return spring is having trouble dis-engaging the contacts. That would explain the longer shut down times, but not the longer start times.

Sorry. I know you asked for ideas--not brain-farts--but, I couldn't resist the opportunity to show off my ignorance with a couple of guesses.

 

I've heard that shutting down that way damages the injectors. Something about leaning out, heat, and them glazing over.

 

Try this for jingles. take toggle switch off, connect wires, start up, and run a bit, then pull wires apart. If it dies like it used to, new switch. Our hydraulic pumps run on toggles, and we have a dozen on hand because of constant on/off.