wirelesswally

To 1979 rx7 first generation. To All, I rebuilt the top portion of the carb the floats were way off. After I performed that the gas pouring into the throats had stopped but now another issue poped up. I changed the fuel filter and went for a test drive. In first and second gear the Rx7 goes like a bat out of hell but when I shift into thrid and above the engin bogs down and speed decreases rapidly downward to where all I can get is about thirty mph. It seems that this starts when the secondaries start to open but if that is what it is why would everything work in 1st and second gear work just as they should. I changed the plugs and retimed the spark but it did not help. When I had the distributer out the engin was cranked by accident and I put it back in by trail and error. I turned the distributer untill the engin would start but could never get the trailing mark to line up but the engine ran strong. I turned the distributer 180 degrees and then could line up both timing marks and that is where the problem started I believe. The engine runs fine at both settings but after I reinserted the distributer 180 degrees from what it was and the carb adjustments were This issue started. How if any would you be able to tell if I am running 180degrees off, could this be what is causing my problem? thanks

Kentetsu

Search the Archive section on the 1st gen tech page for "tdc". This should give you a thread with instructions on how to find top dead center on a rotary.



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wirelesswally

thanks for the tip. I also noticed that after I ran a new rubber gas line from the fuel pump the pump keeps making a clicking noise and does not stop, b4 I did that it seemed that the pump would cp\ome up to pressure and then stop clicking. I installed the filter with the flow pointing towards the pump shoult it possibley be installed towards the tank as I know when I changed changed it gas kept running out and the manual said that I should get some gas but it should stop, mine didn' stop and I had to put a clamp around the line and am wondering if the filter flow should fasce towards the tank the mazda has many odd connections who knows what is proper or not. I did have the gas cap loose when I did this. And again thank you for help. My manuals dont tell you much about certain issues. Wally, 1st generation

RK53

I'm a 2nd gen owner but carbs are carbs. ;-)

Just based on what you are saying it sounds like your floats and gas metering rates are ok but is being fuel flow starved. So in other words, the carb is acting properly but isn't receiving enough fuel to keep the bowl full. AKA a fuel supply problem. I don't think it's a distributor issue. That is usually an immediate and consistent problem if off.

I would say you need to verify the following:

1. Be sure the fuel pressure meets spec.
2. Make sure the float needle valves are opening properly as the float drops and are not sticking or being limited in travel.
3. Do a fuel flow test on the open fuel line at the carb for at least a minute to make sure your fuel flow is not being limited from the pump 'fading' or a restriction in the line/hoses/filter somewhere.
4. Verify your tank is being vented properly and so is not creating a vacume as fule is used. This is unlikely because the effects of this tend to be over a longer time frame then just going through the gears.

Maybe something here will ring a bell from what you're seeing.

Russ

wirelesswally

Russ You may be onto somthing. I took the RX7 out yesterday and it ran fine as long as you didn't kick the secondarys in. it will only starve for fuel when I hit 3rd gear and above. I belive the floats are working properly but I suspect that the new line I ran from the pump could have somthing to do with it. As far as the vacume goes I read that you should always run with the cap on tight. I could try with the cap on loose but I belive that I have already done that. I will preform the pump test but it started after I ran a new fuel hose from the pump to the gas inlet. I did read that the gas inlet is the larger of the two intakes and will check that. The other issue is that the engine will back fire at most lower gears and then I get a cloud of white smoke comes out the tailpipe. I mean a very loud backfire and alot of smokethat lasts for about 10 seconds. To be honest I am thinking about selling the vehicle as it has takin more of my time but i just don't know where to go next. The body is perfect (no flaws) and the compression is good as with the compression valve releast. I might put on e-bay but don't have a clue as to what to ask. I'm lloking to get a ton of money just to cover the cost of the RX and the time and money I have put into it. I will be a excellent RX that knows hor the carb and fuel systum work. In the meantime I will perform the proceedues you suggusted. Thanks very much for your your input. and I will post the results. Wally