Doc-Watt

Picked up an 86 that had been setting for 4 years, fuel pump was out. Found the gas tank had been honeyed, took 3 days to clean tank and lines, then installed new pump. Then discovered I had no juice at the fuel pump, also the idiot lites on center front panel all not working. Checked all fuses, OK. All Lights work except interior , instrument panel ammeter works, heater control lites work, headlight motors work, starter works. Downloaded wiring diagram and can not find a fuel pump relay. Anyone have any suggestions??? It has bee 18 years since I worked on a rotor motor and that was an 83. https://www.rx7club.com/images/icons/icon9.gif

-=Lil Red=-

iTrader: (24)

check the fuel pump relay that is by the pedals. look under the dash

Slappy360

What did you use to clean out tank?

pfsantos

iTrader: (1)

Let's focus on the power supply for the fuel pump. Start with rechecking all fuses, including those under the hood. When you turn the ignition on, do you hear the main realy click (near the trailing coil)? With ignition on, jumper the pins on the fuel pump test connector - the yellow plug with a rubber surround near the air flow meter (search "sensor pictures reference" with my name - I took pictures). You should hear the fuel pump whine and pressurize the rail. If this doesn't work and the main relay is fine, I would check the circuit opening relay (like a fuel pump relay) mounted near the power steering computer under the steering column inside and below the instrument cluster.

As far as the idiot lights are concerned, see if you get power with ignition switch on acc. on the blue/black_stripe wire, and black/Yellow_stripe wire when you unplug the idiot lights and ground the other lead of the multimeter.

Doc-Watt

Used a heavy duty dish soap. Had to remove tank, douse the tank with 1/3 bottle of straight soap, let it set for half hour on each side to coat and soak the inside walls well with straight soap, then filled with water and let set for 24 hours. While still full next day scrubbed everything I could reach through the fuel pump hole with a brass brush. Drained tank. Continued to scrub anything I could feel with brush, rinsed again. Repeated the 1st day process and used all the remaining soap. Let soak for another 24 hours. Hot water would have helped. Second dumping produced flakes of gunk as big as a quarter. Left about 2 gallon of soapy water in tank, then added 2 to 3 pounds of river run clean rocks from small fingernail size to thumbnail size. Rolled these rocks around in the tank in the areas which are baffled to break loose what was left. Drained, removed rocks, rinsed several times. Drained very well, mopped up remaining moisture, and left tank sit in hot sun for several hours, rotating at various intervals to see if any moisture was present.

Inspection showed at least 95-98% of the deposits were removed. Before this process We tried all kinds of chemicals and nothing worked, not carb cleaner, not mineral spirits, not turps, not methyl chloride, not acetone, it was only by accident that the soap was tried and worked like a champ. The crud at the fuel level in the tank was up to 1/4 inch thick and the bottom of the tank had an accumilation of it, much like brown, guey, sticky sand.

Was cheaper than a new or used tank.

Doc-Watt

Thanks for the come back. Finally printed the 100 pages of wiring diags and was able to locate general location of the 3 relays of importance. Taking test meter to garage, about 5 miles away to do further checking. Will keep informed if I have a running machine or not.

Really was looking for gen 1 and a 12a. But the price was right on this 2 gen. Have a Mikkuni Ramhorn induction manifold with duel 48mm? that I kept from old inventory 20 years ago. Brand new, never been used, thought I might make use of it.

Thanks again.

Doc-Watt

pfsantos
Thanks for the info. Was able to jumper the plug you mentioned, got fuel pump power. Cranked for 5 seconds and she fired up. Discovered the Master brake cly frozen up, replaced, now have brakes. Clutch slave was also toast, rebuilt and now I can shift. Warmed it up and went for a spin, pulled to 90 in 3rd then shut it down at 100. Was fun to get behind wheel of a rotor again. Other minor issues to resolve. Will do a tune next.

Should I replace the relay behind the air box? A new one is about $190, but found a used one reasonable. Thanks again for the heads up info.

jdm12a

iTrader: (3)

ok im having this same problem now, i cant get my fuel pump to come on. i have checked main relay, both are fine. i checked the open circuit relay and it works fine too. how do you jumper the yellow plug just run a wire from one side to the other? thanks

dirteeboy808

iTrader: (3)

I need help with this situation 2............upgraded to Warlboro fuel pump and now the pump doesn't turn on, checked all relays, fuses, etc all fine, but no power going to FP, does the pump use the cover as ground or is it seperate?

S5 TII BTW

J-Rat

iTrader: (2)

You just jumper the yellow test connector together. Turn on the key and the pump should run. If it DOES, then its time to suspect an AFM issue.