sobis1dm

Took my 84 GSL on its first 200+ mile trip yesterday. About 40 miles in, it started sputtering like it wanted to backfire (never did) and struggled. This was at 80mph/4k RPM. I slowed it down a little to 70mph/3500ish RPM and drove it to my destination with no more problem whatsoever.

On the ride back home, it became more of a problem. I could cruise at 70-75 no problem but if I tried to give it more gas, it sputtered out.

If I put the clutch in I could rev it all day to the red and it sounded just fine. The engine seemed to like it when I clutched, revved it a little, and then let the clutch out to get back up to speed. It'd be okay for 15-20 miles and then start sputtering again.

I doctored it home using that method, and now this morning on the drive to work (~10 highway miles) I had no problems getting it up around 85. My fuel pump turns on when I click the key, but I know sometimes on RX7s it's more of a slow death.

My first thought was the pump and filters. Is there anything else I could be looking at? It runs perfectly in the city, and it idles just fine. For all I know it could be the float level on the carb (I have an OER and no idea what I'm doing with it, despite a bunch of reading). It was pretty embarrassing to have my car sputtering out on a highway cruise though.

Twilightoptics

iTrader: (1)

Sounds like filter to start, then maybe pump.

Sure sounds like it's running out of fuel.

13x

what are you using for carb and fuel pump?

sobis1dm

The carb is a 45mm OER, and while I believe the fuel pump is still OEM I'm not entirely sure. 75k on the car. I haven't looked there yet. I'll do the filters tonight and take it for another spin.

I will note too that the gas mileage gets cut in half when it's going through those sputters. I was averaging ~13 mpg on the highway last night.

13x

I know when I went with the 45dcoe I was told the stock pump would not be enough ....

sobis1dm

Hmm, really? I would probably be inclined to agree with that based on my experiences. I should have noted before that I can't floor it. If I'm sitting in neutral and rev the engine, I have to gradually step on the pedal. If I put it straight to the metal then I stall out. It won't even try. Which pump did you decide on? I was reading in another thread that the pump for the GSL-SE was too much pressure for the 12A. But if I need more because of the carb what would you suggest?

Edit: In addition, could the use of the fuel pump with the carb have accelerated the decline of the pump? I've had the car for a month or so and the carb has been in it for ~6 months (according to the PO). It could explain why the problem is just starting to surface. I took a few other highway cruises before with zero issue other than the regular 5000+ sputter I mentioned.

Twilightoptics

iTrader: (1)

Flat out mashing the gas and in initial stall out is a pump shot issue. If you can slowly work through the pump shot to floor it in a few seconds and it stalls out its a fuel starvation issue.