I had to let my vette sit idle in the garage for quite a while (2+ yrs). Should have drained the tank. So Now that I started working on it again, it won’t start. This is after me putting in a new fuel pump. So I decided to open it up again and see if I had done something wrong in the install. Well, surprise! When I took the sending unit/pump out, it was completely corroded and disgusting. So now I am starting from scratch, cleaning out the tank, new sending unit and pump. You know 1 step forward and 5 steps back. The material in the tank is black with the larger pieces feeling and looking like rubber. Thought it might be the pump cover and other rubber pieces in the unit. However, when This stuff dries out which happens fast in AZ, it breaks into tiny sand like particles. It’s like ash or charcoal. So it isn’t rubber. I am in the middle of cleaning and extracting all this mess. So far used baking soda and vinegar. I have managed to get about 95% of the stuff out but still swabbing with stick and clothes like a giant Q-tip and vacuuming the particles out. It will take days to get it completely clean. So was this something that was in the tank maybe stuck to the inside or was it deposits formed by the old gas sitting? Just wondering. Whatever it was, it set me back a long way. It was like I started working on a car that has been sitting for 40 years.

Next, I checked the pigtail running to the pump to see if it is getting power with key on and then while cranking. I put my multimeter on black and the gray wires as in a video I had seen. When key is on, I get 12 volts. However, when cranking there is nothing. That was a surprise. I thought you would get power in both modes if there was no fuse or relay blown. I need so help interpreting this. Please advise.

I have new sending unit and pump ordered as well as in line fuel filter. Plans are to check each and every line for debris all the way to the fuel rails. I think I will also cut the old fuel filter in half to see if there are particles like seen in the tank.

Thanks in advance.

 

This is the black rubbery sludge I removed from the tank. Nothing like it was wet.

Condition of sending unit and pump. These were clean and the pump was new.

 

It looks like a combination of ethanol mold and moisture contamination leading to corrosion.
moisture can build up in partially filled tanks due to repeated temperature cycling and resultant condensation inside the tank.
ethanol mold aka whiskey mold is the black gooey stuff. The mold eats ethanol and causes the fuel to degrade faster than straight gasoline.

 

Hi Talfryan,

Sounds spot on. Have never heard of the mold you are referring but it reminds me of the time I had a bacteria, Pseudomonas sp. (grows mostly in gasoline) in my motorcycle carbs which clogged the passages. Had never heard of that one either.

So being in AZ where we get wide and extreme temp shifts and very much altered fuel (added ethanol), especially, in summer, it sounds like the makings of the perfect storm. Will have to research how best to decontaminate or “sterilize” the inside of the tank. Thanks for satisfying my curiosity: could prevent me from repeating the same situation later.

Now on to the fuel circuit/relay wiring issue.

Thank you,

WEK

 

Really there are, potentially, two separate problems with my vette. It had a mechanical issue: dirty tank, sending unit/pump, possible lines and fuel filter. But the other problem is even worse. I don’t know if I have a fuel pump relay failure. Has the car been running on a bypass mode created by the PCM? So, I took the plastic inspection plate off the passenger side dash and took out the glove box. I can barely see the relay from underneath and can touch it but not remove it with my hand. From the top, you can’t even see it because of the AC tunnels. I have a plan. The one audio system does not work so since I will replace that anyway, the amplifier and associated wiring is coming out. This is going to take a while but I will make room for a better arrangement of the relays and fuses under the passenger side dash. Then fabricate an aluminum inspection door which will replace the plastic one and some of the trim (carpet). Wondering if anybody else has done this. I can not stand it when it is practically impossible to get to something you need to fix or maintain. So we will see how this turns out when I get a little more into it.

if anyone has any great alternative ideas or suggestions feel free to hop in!

WEK

 

Here is what I have done to make the relays more accessible from now on. So I took the relay brackets off their slide mount and turned them around to face toward the back of the car. I broke one so that should be an interesting search. Don’t know the correct name. As of now, I have the relays rearranged but still haven’t remounted the secondary fuse panel. I did remove the amplifier so there is a little more room in that very tight space. I also removed a small duct aiming at the passenger’s feet that ran between the relays. It wasn’t even connected well at the main trunk. I plan on using a flexible tube and clamp. I don’t think the passenger will mind as long as the air is getting to the right place! That also freed up a small amount of space.

All of this was possible because I cut a large inspection port for the area with a hole saw and cut off grinder. After the wires, relays, and fuses are in their new positions, I will cover the inspection port with an aluminum panel or maybe another glove box cover if I can find a good fit. I don’t like the carpet covered panel in front of the passenger anyway. But that is a cosmetic thing so it will work out.

I need to find that bracket holder if anybody knows where to find those small parts, great. Check out the relocated relays.

WEK


New inspection port

Relays rearranged to face toward opening. FP relay removed for testing.