I ran into a problem getting my Bronco to start recently after upgrading all the battery cables and replacing some brake parts. The truck wouldn't start at all. I could initially hear the pump priming when the key turned ON but that was intermittent, sometimes you could hear it and the vehicle would almost start and run and other times it didn't prime at all.

I purchased a fuel gauge to read the fuel pressure from the fuel rail and never saw the pressure come up. It was always 0 psi. This is after the pump had completely quit priming so not unexpected. This is the reason that I dropped the tank to replace the pump.

Background on the pump.

I dropped the tank in 2010 while I was getting the Bronco ready for the road after an engine replacement. The pump wasn't working at the time so I replaced the pump with one from AZ or O'R here locally. I kept the sender and float, etc since they were working fine at the time.

After replacing engine, fuel pump, and a bunch of other things I toodled around for a few days looking for a shop to do the AC upgrade from R12 to R134a and one hot day while heading home with estimates in hand the front brake locked up burning up the rotor, etc.

I parked the vehicle until 2012-2013 when I got back into it and replaced rotors, calipers, pads, etc. and cleaned the rear brakes and replaced all the rubber brake lines and bled the brakes. I also began some interior work replacing the dash bezel because broken connectors caused it to rattle all the time and the rear window switch had broken from it's top screw so it hung in the hole and was awkward to use.

I also repaired mount points on the door panels when it became necessary to rebuild the power window motors. The driver's side motor quit on me one day just after I had test driven the vehicle with the new brakes and just before it started to rain. I finally got all the interior upgrades and things fixed and went to work installing the battery cable and alternator upgrades that I bought in 2008 from the injection guy. That was fun and I was almost ready to put it back on the road in search of someone to do the AC upgrade when I discovered that it would no longer start and run.

Several years since I initially began the upgrades on this thing. It's in great shape but needs paint.

Unfortunately I now have this fuel tank, fuel pump, fuel system problem.

The funny thing about this is that the fuel float appears to be entirely dissolved except for the solder ring. I'm 99% sure it had a 2-piece soldered brass float when I installed it in 2010. All I can find of that now is the solder ring which you can see in one of the pictures in the album linked below.

I have an album of pictures that will show what I have today.

[1992 Bronco Fuel Tank and Pump](https://imgur.com/a/DwtcG#3)

What are my options?

How do I clean the tank?

Do I also remove or replace the fuel lines?

What are the chances that my newly rebuilt injectors will need to be pulled and rebuilt?

What about other engine parts?

I'm pretty bummed about this as I was starting to see a conclusion until I dropped this tank.

What caused the reddish varnish or gunk to be deposited on the inside of the tank?

Thanks for all your ideas.

Sorry for the wall of text but I thought the extra information might be useful. I'll hang up and listen now.

 

The varnish is classic gas gone bad over a long period of time. Usually smells real bad, too.

I would suggest filling up the lines with solvent, and blowing it out with compressed air. Probably a couple times over, till it blows out clear (catch the solvent so you can tell).

Will need to take out and discard the old fuel filter first, and clean lines section by section.

The Fuel Rail could be gummed up, and the Fuel Pressure Regulator too. You can clean the rail with solvent, but you may just have to replace the FPR.

Also clean the fuel return line that goes from rail back to the tank.

Taking out the injectors, you might be able to carefully blow some solvent through them, by turning them on with 12 volts.

Gas gone bad can make a real mess!

Cleaning gas tank - with tank and all fittings removed, can put a few handfuls of rounded gravel inside the tank, like small river pebbles. Duct tape closed all openings except one big one, put in a few gallons of water with garden hose, then roll every which way on grass, over and over and over. Need to really turn it into a sport! The gravel acts like an abrasive, and with rounded gravel will not scratch up galvanizing.

Dump, and re-use gravel, refill with water, do again. When you can't get it any cleaner, rinse good with water, then let it dry out completely. Then spray in a nasty solvent like CRC Brake Clean, and see if you can get the last of it to dissolve out and dump. Wash with water one last time, and air dry.

I've done this on carburetor cars, and I learned that cleaning everything was the only way I could banish the problem for sure. Otherwise, an area left varnished-up but flowable, started to let loose crud later on when new gas was in, and everything seemed OK at first... for a while... till it wasn't.