Problems with 84 fuel system

[elkabong]

Well I thought I had cleaned it good enought but ...........

Here is the deal. My fuel filters have only lasted about 50 miles before they get clogged and require changing. My 84 mainly sat in the garage for the past 4 years. It got started every now and again but not driven. As a side note the person I bought it from is a good friend who just wanted to get rid of the 84. Imagine that, just wanted to get rid of it. Anyway.......

It has 25K miles. I have so far drained the tank, cleaned it out and replaced the 84 fuel pump with an 85 and new strainer (sock in my day). Yesterday I checked it again (after replacing another clogged fuel filter) and decided to blow compressed air through the line before I connected the fuel filter. I zip tied a terry cloth towel on the end that plugs into the fuel filter to see what was coming out. A brown substance was deposited on the towel after I blew it out. I kind of expected this becasue of the lack of driving. My thinking is it is dried gas. I filled out the fuel line with gumout and let it set a while and then blew it out again - more brown stuff. After cleaning with gumout and blowing it out on the towel there is less brown stuff.

So, what to you Vette guru's think my next step should be? I was thinking about replacing the solid tubing with new stuff. How difficult would that be? Should I just buy 3/8 tubing (I think that is the proper dimension but need to remeasure) and break out my handy dandy tubing bender to match the profile when removed or should I buy some that is prebent (dealer or aftermarket). Or should I just see if I have cleaned it out good enough and let nature take its course?

Thanks in advance.

 

[vigman]

I would install a temp filter

Like a big MARINE style fuel filter and have a pressure gauge on the OUTPUT side of the filter.... the marine elements I'm thinking of are about the size of an oil filter.. will look today and give you some ideas...

the other way to splice it in ( without messing up the stock fitttings) is to get some brass
( bronze) 90 degree elbows to hose nipples and run the lines UP( with some heat sheild.. or secondary covering ) to the firewall area so the filter is EASY to get to.

I think if you do not replace the tank & do the big filter thing.. it will take about 2-3 tank fulls to Flush the entire system out.

Vig!

 

[elkabong]

The tank seems to be clean I ehecked/inspected it yesterday when I pulled the fuel pump out. I would like to avoid replacing the tank of possible. Where would be a good place to get a tank. I don't think using one from a wreck/salvage would be good because I may have the same problem.

Thanks for the idea for the marine filters. I look forward to your ideas.

Thanks.

 

[Hib Halverson]

So, what to you Vette guru's think my next step should be?

Thanks in advance.

You need to either clean-out or replace your fuel tank.

Changing filters--even "marine" filters, isn't going to fix the problem, especially if the problem is degradation of the rubber bladder inside the tank or corrosion of the tanks walls themselves.

 

[elkabong]

Here is another thought. I just realized that the first strainer that I replaced when I installed the 85 fuel pump is flatter than the AC Delco I put in last night. The AC Delco strainer is rounder (kind of tough to explain). Would a flatter strainer cause a restriction in the fuel flow. I just checked (blow test) the filter I replaced last night and it seems to be fine. What do ya think?

Here is an image of the flat one.

The AC Delco is the same lenght but about 1" in dia.

Also, If I put a marine filter close to the tank would I still need a regulator because the filter would be before the regulator? Of course I would not want anyone to rearend me! I am thinking of a temp solution so I can run some tanks through the fuel system and then mount/regulate it properly as you suggested. I like the idea of having a HUGE fuel filter.

 

[JonM]

A new tank will run you about 600 bucks. If it were me, I would drop the tank, bring it to a radiator repair shop and let them clean it out. (call them first) As for the tubing, in the plumbing department of Home Depot or any plumbing supply house, they sell small tubing that is softer then the stuff you use for your sink. It can be molded by hand. Its what they use behind your refridgerator if you have an ice maker.

 

[elkabong]

Thanks. The inside of the tank seems clean and there is not deteriation on the walls. I checked it with a borescope. So, I guess I will drop the tank get it cleaned and head for Home Depot. Are you referring to copper tubing? I did not know they sold other types.

 

[JonM]

Thanks. The inside of the tank seems clean and there is not deteriation on the walls. I checked it with a borescope. So, I guess I will drop the tank get it cleaned and head for Home Depot. Are you referring to copper tubing? I did not know they sold other types.

Yes the copper tubing comes in rolls,just get the correct size...remember when you are cleaning the inside of the tank, there is a bladder inside.

 

[elkabong]

I did not see a bladder. All I saw was the inside with a black coating on the inside of the tank.

Right now I am cleaing the injectors and they have a black stuff on the ends.

The solid fuel line is now clear. I just checked it and the brown crap from blowing it out is gone. What about the regulator? I don't know that much about the fuel system - but I am learning quickly. Trial by fire!

 

[JonM]

I did not see a bladder. All I saw was the inside with a black coating on the inside of the tank.

Right now I am cleaing the injectors and they have a black stuff on the ends.

The solid fuel line is now clear. I just checked it and the brown crap from blowing it out is gone. What about the regulator? I don't know that much about the fuel system - but I am learning quickly. Trial by fire!

The black coating is the bladder. Did you remove the injectors from the car? If you did, DON'T mix them up. They have a screen in each of them. Advanced Auto has a rebuilding kit for the regulator Part # 800-261 Also each injector has a screen in each Part # 800-71

If you need any pics ...let me know

 

[elkabong]

I did not mix them up. I took on off at a time. One of the O rings was toast I did notice that the screen slots do not line up with the holes on the injectors. The slots on the screen slightly plug up two of the wholes on each injector. Is this normal? I don't think it should be.

The injectors have two numbers the first on the top is GM523770*RPD and the second on the bottom is 5253GM.

 

[JonM]

You should just twist the filter onto the nozzle end against the injector base. The filter is cone shaped, the large end faces up so it covers the raised rib at the base. Lube the small"O" ring with Tranny fluid then push it on nozzle end of injector. The ring should be up against the filter. I don't think it matters about the holes and the filter, but if it makes you feel better not to line them up..so be it