Cleaning the Fuel System

[Justin51982]

So I just finished reading this great write up.....

http://dmctalk.org/showthread.php?63...-start-the-car

I had one thought though in regards to cleaning the fuel lines from the tank back to the fuel distributor....Instead of running the B12 through all the lines, wouldn't it be just as effective, but cleaning and easier to use my air compressor and a tapered nozzle and blow the system out that way?

Has anyone done that? If so had success? I'm just curious because I am planning on tackling a good portion of my fuel system this weekend.

[OverlandMan]

So I just finished reading this great write up.....

http://dmctalk.org/showthread.php?63...-start-the-car

I had one thought though in regards to cleaning the fuel lines from the tank back to the fuel distributor....Instead of running the B12 through all the lines, wouldn't it be just as effective, but cleaning and easier to use my air compressor and a tapered nozzle and blow the system out that way?

Has anyone done that? If so had success? I'm just curious because I am planning on tackling a good portion of my fuel system this weekend.

My 2 thoughts here would be moisture and amount of pressure (assuming 90 psi).

Are your lines original? If so, I'd highly recommend replacing ALL of them sans the metal lines. This is coming from someone who's car had a 20 second fire due to a pinhole in a fuel line.

[David T]

My 2 thoughts here would be moisture and amount of pressure (assuming 90 psi).

Are your lines original? If so, I'd highly recommend replacing ALL of them sans the metal lines. This is coming from someone who's car had a 20 second fire due to a pinhole in a fuel line.

The logic in using a solvent and flushing it through the lines is that it hopefully would break down any sludge and wash it out. Air won't do that, it will only blow it out if it is already loose. The amount of moisture in the compressed air is negligible and even at 90 psi you won't hurt anything. A lot of this is a judgement call. How intensive you get is a function of how badly the fuel system is fouled up. One good way to judge is the amount junk at the bottom of the fuel tank.

[Justin51982]

The logic in using a solvent and flushing it through the lines is that it hopefully would break down any sludge and wash it out. Air won't do that, it will only blow it out if it is already loose. The amount of moisture in the compressed air is negligible and even at 90 psi you won't hurt anything. A lot of this is a judgement call. How intensive you get is a function of how badly the fuel system is fouled up. One good way to judge is the amount junk at the bottom of the fuel tank.

I know that at least portions of the fuel system, lines and whatnot were replaced when Hervey owned the car, It also looks like he updated the fuel pump and baffle in 2004 (according to the date on the part) and I know the last time it was ran was 2000-2001.

The tank was pretty empty, there is a little bid of sediment at the bottom, but the take was pretty much empty when I pulled the fuel pump and you can see more silver than black at the bottom of the tank.

I also now have new fuel stainless distributor lines, maybe I'll start out by cleaning the tank it self with B12 and then disconnect the fuel distributor and push air through the system. Depending on what comes out from that, I should be able to better determine if I need to get more invasive.

[David T]

I know that at least portions of the fuel system, lines and whatnot were replaced when Hervey owned the car, It also looks like he updated the fuel pump and baffle in 2004 (according to the date on the part) and I know the last time it was ran was 2000-2001.

The tank was pretty empty, there is a little bid of sediment at the bottom, but the take was pretty much empty when I pulled the fuel pump and you can see more silver than black at the bottom of the tank.

I also now have new fuel stainless distributor lines, maybe I'll start out by cleaning the tank it self with B12 and then disconnect the fuel distributor and push air through the system. Depending on what comes out from that, I should be able to better determine if I need to get more invasive.

Actually Acetone works very well to clean the tank. Then you can put some B12 in the tank and run the pump. That will circulate the B12 from the tank, past the accumulator, through the fuel filter and to the mixture unit where the pressure valve will dump it back to the tank. Once you have that circuit clean remove the fuel injectors and push down on the air sensor plate to get the B12 to come out of the lines going to the injectors. When you have B12 coming out clean, install the fuel injectors and see what the patterns look like with fuel. Once you have them all spraying replace the fuel filter and if necessary, the accumulator. Replace any deteriorated parts in the tank.

[Justin51982]

Actually Acetone works very well to clean the tank. Then you can put some B12 in the tank and run the pump. That will circulate the B12 from the tank, past the accumulator, through the fuel filter and to the mixture unit where the pressure valve will dump it back to the tank. Once you have that circuit clean remove the fuel injectors and push down on the air sensor plate to get the B12 to come out of the lines going to the injectors. When you have B12 coming out clean, install the fuel injectors and see what the patterns look like with fuel. Once you have them all spraying replace the fuel filter and if necessary, the accumulator. Replace any deteriorated parts in the tank.

So are you suggesting to leave the fuel distributor connected and let the system run a complete cycle more or less?

[David T]

So are you suggesting to leave the fuel distributor connected and let the system run a complete cycle more or less?

Yes, unless you know it is so messed up that it has to be disassembled to be cleaned up.

[DMCMW Dave]

It's extremely important to flush the solvent out all the way through the injectors with fresh gas when you are done. If you leave any of the B12 (or the like) in the system it will damage internal rubber parts pretty quickly.

[TTait]

It's extremely important to flush the solvent out all the way through the injectors with fresh gas when you are done. If you leave any of the B12 (or the like) in the system it will damage internal rubber parts pretty quickly.

That was my original thought - I've done the reference procedure twice and have not had any issues, but I did bypass the FD, CPR, injectors, etc. and I flushed with gas immediately after to get the B12 out of the accumulator.

[AZ-D]

Sorry to revive a dead thread, but I though it better than starting a whole new one. At this point.. I am just trying to see if I can get the car to fire up before I move onto the next thing. If it won't fire, no reason to worry about anything else yet.

I pulled the lines from the pump off the hard lines at the front and it is a little gummy looking inside the end of the hard line. I took a small pick and its soft brown material that comes off easily. I don't think I need to get as involved as the "How to" suggests and it seems like just running some fresh gas thru the line would clear it up significantly, but I don't want to push any of that material to the distributor.

Can I disconnect the hard line at the fuel filter and jump the RPM relay to pull fresh gas through the line and see how it comes out? Or is there some other version of that to get the line clear?