RX-7 Fuel problem

[Micke Tanno]

When I first start the car and step on the gas it runs real rough and then it dies,I repeat this about 3 times,once it stays running and I give it gas say at a stop sign it will sound like it's choking and some black smoke will come out of the muffler.any advice would be appreiciated.

[KevinRX7]

Could be a few things.. what year is your car? how many miles? any mods?

[RageRX7]

Ya, a little more info is needed, sounds like it's flooding, running too rich

[Micke Tanno]

When I first start it sometimes it floods and I have to disconnect the fuel connection in the hatch,start it again and connect it so the car will stay running.Then as I'm giving it gas it sounds real choppy and will stall if I don't keep giving it gas as black smoke is coming out of the muffler,but then after a while it will run just OK not at it's peak.It's an 86 RX-7 GXL 1.3 auto no mods no turbo and the engine is about 5 years old.

[Jimbo]

hmmm.

it sounds to me based on that, that your injectors could be failing, or the timing is off. When it is running sort of ok, does it feel smooth, or a little whump whump like?

The black smoke is just some unburnt fuel and a little oil, so the other possibility is that your spark plugs are shot, or gapped wrong. So instead of combustion, your just pumping out fuel, which would also explain the lack of power.

I'll think about it some more, I need to head out tonight, but my gut says, new plugs, first off, easy to do.

[Micke Tanno]

I pulled the connections to the fuel injectors,don't think it's that,I'll try the spark plugs,Thanks Jimbo

[FCROTARY]

I would have said what Jimbo said, but that's about the extent of my knowledge.

I'm sure you're not the first person to go through this good luck!

[KevinRX7]

What do you mean you pulled the connections to the injectors? did you do that and crank it over? that would make it worse.. unless I'm not getting you.

I would pretty much agree with Jimbo and check your plugs first off. When you pull them out, see if they are all black and gummed up, if so, then it's too much fuel/not enough spark. clean them up and gap them to specs, or just get a new set if they are old. Worst case is it's cheap maintence.

With the smoke and all, it's kinda backwards to the typical problem with these cars, usally vacuum leaks. They almost always run lean and stall out, not run rich.

I missed the obvious, could be your throttle posistion sensor, very common problem on the older rx7's and normally needs replacement. it's right on the top of the engine 3 prongs with wires coming out of it. No real way to test them though, so you'd have to commit to replacing it on a lark. You can unplug it though and see how it runs, if it's no differant, then it's probably it.

I hope you're mechanically inclined though, since it's hard to diagnose things over the internet.. it will take some fiddling around with things..

How's your compression?

[Micke Tanno]

I pulled them off one at a time while the car was running to see if their was any change in the idle,their wasn't.I agree with all you guys I think it's the plugs but the funny thing is I just changed the plugs about 6 weeks ago,could it be the fuel filter or injector if it's not the plugs ?

[ConeDodger]

Not likely the fuel filter, but as said above cheap maintanence. If you unpluged your injectors and there was no change, then it really sounds like that is your problem.

Do the plugs, if there is no change, then look at your injectors for sure. They only last so long, you can try some injector cleaner frist and see if that helps, sometimes when the car sits too long, the gas gets gummed up and plugs them.

[Supersonic]

Ya, I think these guys nailed it.. let us know how it goes.. man I hate trouble shooting these things sometimes

[Micke Tanno]

I changed the plugs,air filter and added Red Line fuel system cleaner to it and it seems to run better but still every time I start it it floods and I have to disconnect the fuel pump connection in the back to start it and then quickly connect it back.And I mean EVERY time I start it I have to do that,the battery is new and so is the starter,any suggestions ?

[RageRX7]

If you did all that, it really is starting to point to the TPS, it may be pumping in way more fuel then you need at start up, which will keep flooding the engine.

when you disconnect the pump, get it running, then reconnect, does it run fine after that, or will it continue to flood if it sits?

what's your rpms when it's idling?

[Micke Tanno]

It'll run fine after that until I have to start it again and I do my disconnect routine again,the RPM's after starting are about 800

[KevinRX7]

considering that, it's one or both of these things.. your throttle posision sensor and fuel pressure regulator.

What's happening, is that the sensor is kind of stuck on like a choke, where it feeds too much fuel in as if it was cold. The FPR is what supplies the proper amount of fuel, and it could be dumping too much in.

I had a faq somewhere about how to tweak the tps, I'll see if I can find it.

[Micke Tanno]

I was driving home just now say about a 10 mile ride and about half way through it started choking again,the more gas I gave it the worst it got.I have an extra FPR and I'll try that tomorrow,Hey exactly where is the TPS located,I can't seem to find it.

[KevinRX7]

It's a little rectangular box, sits right on top of the engine, has 3? wires comeing out it. Looks like a tetris peice if that helps.. pretty easy to find. I don't have my car here, or I'd take a pic.

[Micke Tanno]

I just want to say thanks to everyone,I changed the FPR,that wasn't it so I changed the TPS,that WAS it,it starts right up and moves like a mother.If any of you guys ever come to Vegas look me up,I owe you.Thanks to you guys I knew what I needed,took it off my old engine and saved alot of money.so I owe you guys. Thanks again, Micke

[RageRX7]

Awesome Bud, congrats.. that's what we're here for, But Kev should get the props, he was the first to mention the TPS

[AZNPWR]

Glad it worked out for you Micke.