Evening.

Recently got my hands on an 85 GSL that had been sitting for a considerable length of time. Overall it isn't in bad shape. However, after burning the candle at both ends all week and hoping I'd have her finished today, I ran into an issue: can't get fuel to the bowls. Tested the fuel pump in and out, close to 3 psi. Pulled the pickup and return piece to make sure the strainer was clear. There is fresh fuel in the tank, lines are hooked up correctly, etc.

So, no fuel=no joy . I know she was allowed to run dry before she was stored. Tried searching for fuel flow problems and couldn't find anything. Any advice would be appreciated.

 

carb rebuild? have you check for flow/pressure directly at the carb inlet hose?

 

Pulled the fuel inlet hose to the carb and shoved a cup underneath it to see if I could get a volume measurement the lazy way. No fuel there either. Beginning to think it might be a clogged line.

 

did you check...or more importantly, replace the fuel filter? that should be step number 1 in buying any car, especially an rx-7 thats been sitting for a longer period of time. they should be changed out every year. as soon as you know the filter is fresh and that the fuel pump is pushing decent fuel volume/pressure, then check the lines for blockage

 

...I feel like a dummy right now. I went and bought a fuel filter the day I got the car and forgot to put the damn thing on. I'll try that today and find out if that's the issue.

Edit: I like the .gif, lol

 

bicycle pumps fit right on to hard lines and blow the whole line out.

 

Well, got it to flow fuel, ran her for about 30 sec, and she drank the bowls dry...I'm guessing that the fuel pump relay is de-energizing for some reason.

 

As an aside (did it this way because it wouldn't let me edit for some reason), turns out the fuel tank pickup and return lines were clogged, so the bicycle pump and some safety wire were put to use. I'd like to shake the hand of the crafty bastard that came up with that idea. Swapped the fuel filter too in the process since I was there and I had one handy. As previously stated, it appears that the fuel pump relay is de-energizing post ignition (it operates prior to turning the key and then clicks off after she's running; cut it loose from its retainer and held on to it while I cranked it to verify). The relay is not original due to some hack and slash wiring work. If memory serves, earlier models didn't have a cut relay for the fuel pump, and since they run off switched 12VDC anyways, is there a problem with just deleting the relay and jumping the requisite wiring to keep the pump running when 12VDC is present?

 

There really shouldnt be an issue with retro modding the fuel pump circuit to earlier design. I k ow for fact that the s1 and s2 rx7's simply supplied power to the fuel pump via fuse box through the ign switch. You could use this as an excuse to make a simple anti theft devise and put the pump on your own hidden toggle switch and wire it your own way

 

Fuel flow problem solved, gentlemen. Thanks for the help...now to seek a pesky intermittent vac leak or some similar issue...it'll idle fine for several minutes then sputter and die if I don't bump the throttle. And spongy brakes, but no fluid loss. Hmm. I already removed, cleaned, and reinstalled the master cylinder (cup seals looked good, not deformed or munched). Tried clamping the booster vacuum line and there was no change in idle speed. I lack a can of carb cleaner to do the dummy test. Any idea what manifold vacuum is supposed to be?

 

Glazedham42 posted this link to awonderful article that explains manifold, ported and venturi vacuum. http://www.lbfun.com/warehouse/tech_..._explained.pdf