Fuel Tank Crud? Redoing Fuel Lines, Etc. Options

[kenshapiro2002]

So, in my continuing fuel starvation saga (another thread), I'm almost ready to rebuild the webers. Rode her hard again yesterday, and she ran pretty nicely for awhile and eventually started to starve very hard at really hard throttle. Took a very good look in the tank, and the walls look pristine, but in the circular baffle area where the sock is, there were many very tiny pieces of black crud, and the sock, though very hard to see well, looked pretty dark too.

Opinions?

Also, I'm thinking that since my fuel filter was pretty clean, that the sock might be my real problem...should take care of that before making the carbs clean and possibly getting more crap in them.

If I do pull the tank and replace the sock, shouldn't I replace the fuel line back to the engine? Any threads on that? Can I just hook a new line up to the old and pull it through?

Thanks in advance,
Ken

[jmill]

Explain this "starvation" you have. Does it just bog down or do you get pops out of the carb too. No lean pops and just bogging means too much fuel or ignition issues.

Starvation with carbs happens when the fuel supply can't fill the float bowl as fast as it's used. You suck down the float bowl and your mains run lean. You then get a bunch of pops and snaps from the carbs. The engine then usually dies because the idle jets get their fuel from the main fuel wells and those are too low already. You then can't start your car until the fuel system fills the float bowls up again.

Pull out one of your ETs and let us know what main and ac jet your running along with what ET you have. They are easy to remove. All you need is a standard screwdriver. Be careful when you reinstall it. Be gentle and don't cross thread it.

I'm trying to help you here but you haven't answered this question from your other thread. There seems to be a few threads of yours on this same issue. It would be a bummer if you go through the work of changing the sock and that wasn't your issue. Starvation usually happens after a hard acceleration in one of the higher gears. In another thread you said it happens more often in first gear which has me wondering if it truely is a fuel starvation issue. It would help if you explained what happens.

Either way if your sock is clobbered change it. You can even remove and clean it if it's in one piece.

[Cevan]

Don't bother cleaning the sock. If you go through the trouble of removing it, just replace it. They're something like $7. And IIRC, there is a crush washer built into the end of the sock.

[IronHillRestorations]

Find a radiator shop that will clean and seal your tank, and change the strainer sock at that time. I would probably replace all the rubber fuel lines regardless, and put in a new fuel filter too, after you have the tank cleaned.

No you can't just pull new lines through. There are plastic lines in the tunnel and the flex lines connect to them. There's enough evidence to support a bias against keeping the stock plastic lines, particularly if the visible portion of your plastic lines are at all brittle.

Chris Foley - CFR a banner advertiser on this site, makes an excellent set of stainless fuel lines that will last longer than you. If you have carbs, and never ever plan to go back to FI, or never ever plan to run a return fuel line (not needed for street car), you can use just a single fuel line.

[kenshapiro2002]

Sorry...didn't see the other post you made on that thread. It sounds exactly like what you're describing in your second paragraph...I get the pops and snaps and then it starts to completely die until I let off. On the way home from CT. it did completely die, and I had to wait 10 minutes to restart it. Then it was "OK" as long as I just maintained a steady pedal and no hills showed up to tax it or cause me to give it more gas.

Let me go pull an ET and get back to you...thanks a million.

Does the condition of my fuel tank sound good, bad...? Like I said, the tank looks nice and shiny, but the area surrounding the sock looks a little dirty and the sock looks dark.

Explain this "starvation" you have. Does it just bog down or do you get pops out of the carb too. No lean pops and just bogging means too much fuel or ignition issues.

Starvation with carbs happens when the fuel supply can't fill the float bowl as fast as it's used. You suck down the float bowl and your mains run lean. You then get a bunch of pops and snaps from the carbs. The engine then usually dies because the idle jets get their fuel from the main fuel wells and those are too low already. You then can't start your car until the fuel system fills the float bowls up again.

Pull out one of your ETs and let us know what main and ac jet your running along with what ET you have. They are easy to remove. All you need is a standard screwdriver. Be careful when you reinstall it. Be gentle and don't cross thread it.

I'm trying to help you here but you haven't answered this question from your other thread. There seems to be a few threads of yours on this same issue. It would be a bummer if you go through the work of changing the sock and that wasn't your issue. Starvation usually happens after a hard acceleration in one of the higher gears. In another thread you said it happens more often in first gear which has me wondering if it truely is a fuel starvation issue. It would help if you explained what happens.

Either way if your sock is clobbered change it. You can even remove and clean it if it's in one piece.

[jmill]

Sounds like your on the right track. If the tank is shiney I wouldn't mess with it. Replace the sock and wipe out the gunk around it. I would change the fuel lines myself. It's cheap insurance. Are you going to upgrade that fuel pump? If the sock replacement doesn't fix it thats what I'd change next provided your carbs are set up correctly.

[kenshapiro2002]

Main= 115
AC Jet = 200
ET = F11

Looked at all pieces with a jeweler's loop and they look spotless.

Explain this "starvation" you have. Does it just bog down or do you get pops out of the carb too. No lean pops and just bogging means too much fuel or ignition issues.

Starvation with carbs happens when the fuel supply can't fill the float bowl as fast as it's used. You suck down the float bowl and your mains run lean. You then get a bunch of pops and snaps from the carbs. The engine then usually dies because the idle jets get their fuel from the main fuel wells and those are too low already. You then can't start your car until the fuel system fills the float bowls up again.

Pull out one of your ETs and let us know what main and ac jet your running along with what ET you have. They are easy to remove. All you need is a standard screwdriver. Be careful when you reinstall it. Be gentle and don't cross thread it.

I'm trying to help you here but you haven't answered this question from your other thread. There seems to be a few threads of yours on this same issue. It would be a bummer if you go through the work of changing the sock and that wasn't your issue. Starvation usually happens after a hard acceleration in one of the higher gears. In another thread you said it happens more often in first gear which has me wondering if it truely is a fuel starvation issue. It would help if you explained what happens.

Either way if your sock is clobbered change it. You can even remove and clean it if it's in one piece.

[kenshapiro2002]

I have to believe the carbs are set up correctly as it was "built" in 1989, not a new build. The car was brought out of storage by a team of Porsche techs who have been rebuilding and fixing Porsches for almost 40 years. It ran great until I filled it up a few hundred miles after leaving CT on my way back to MD. That's when the trouble started. It was either bad gas or the fresh fuel (vs. old fuel with StaBil in it) loosened up enough crap to clog the sock, or carb or fuel pump. The filter element had about 5-10% of it covered with microscopic black crud, but was (of course) 90-95% clear. I figure it;s most likely the sock or the carbs, So far, the emulsion tube with main and AC jets looks clean as does the idle jet I pulled. Since the filter was relatively clean, I'm thinking (and I'm far from an expert here), that the crud is in the sock.

Sounds like your on the right track. If the tank is shiney I wouldn't mess with it. Replace the sock and wipe out the gunk around it. I would change the fuel lines myself. It's cheap insurance. Are you going to upgrade that fuel pump? If the sock replacement doesn't fix it thats what I'd change next provided your carbs are set up correctly.

[jmill]

Main jet seems small to me. I'd run a 1.25.

[kenshapiro2002]

Educate me on that. It's a 1.7 with a 1911 big bore kit. I'm assuming the jetting was done back in 1989 when all the work was done. Even if a 1.25 would be an improvement, it certainly isn't my current problem, is it?

Main jet seems small to me. I'd run a 1.25.

[silverteener]

I had a fuel starvation problem. Finally looked inside my tank and found the problem. I would pull the tank and have it boiled and sealed. it solved my problem anyway. If your tank has never been pulled and the lines replaced it would be time well spent anyway. Good luck


(IMG:style_emoticons/default/beerchug.gif)

[kenshapiro2002]

What did your tank look like? Like I said...mine looks beautiful other than some micro flakes around the base near the sock and the sock looks "dark" and collapsed to me.

I had a fuel starvation problem. Finally looked inside my tank and found the problem. I would pull the tank and have it boiled and sealed. it solved my problem anyway. If your tank has never been pulled and the lines replaced it would be time well spent anyway. Good luck


(IMG:style_emoticons/default/beerchug.gif)

[jmill]

Educate me on that. It's a 1.7 with a 1911 big bore kit. I'm assuming the jetting was done back in 1989 when all the work was done. Even if a 1.25 would be an improvement, it certainly isn't my current problem, is it?

Having mains that are too small will cause those same symptoms. You can verify that by idling your engine for a few minutes and then rev the engine up close to redline and hold it there for a few seconds. Try it unloaded and loaded. If you get a lean pop you can be pretty sure your not getting enough fuel from your mains. Holding it at high RPM for a few seconds takes the accel pumps out of the equation. They can mask small mains if you don't hold it there for a bit. Just be sure to let it idle for a minute before you do the test. Starvation due to fuel delivery problems takes longer to happen because you need to draw down the float bowls to make it happen. If you get no pop in the test your mains aren't the issue.

Look hear: http://www.triumphspitfire.com/jets.html

Check out the Fiat jet sizing. The Fiat ran a 40 idf with 125 mains and 210 ac jet with 32 vents an F11 ET. Swapping to a 210 ac jet will lean you up a bit more at high rpm.

I personally think you have a combination of fuel delivery and carb issues.

[kenshapiro2002]

Here's a shot I just took of my sock and surrounding area. The sock looks crimped and dark to me. See the specs on the floor? The rest of the tank looks unrusted for sure, but the guy kept it filled and Stabil'd, so I'n guessing it should. Whattaya think?

Educate me on that. It's a 1.7 with a 1911 big bore kit. I'm assuming the jetting was done back in 1989 when all the work was done. Even if a 1.25 would be an improvement, it certainly isn't my current problem, is it?

Having mains that are too small will cause those same symptoms. You can verify that by idling your engine for a few minutes and then rev the engine up close to redline and hold it there for a few seconds. Try it unloaded and loaded. If you get a lean pop you can be pretty sure your not getting enough fuel from your mains. Holding it at high RPM for a few seconds takes the accel pumps out of the equation. They can mask small mains if you don't hold it there for a bit. Just be sure to let it idle for a minute before you do the test. Starvation due to fuel delivery problems takes longer to happen because you need to draw down the float bowls to make it happen. If you get no pop in the test your mains aren't the issue.

Look hear: http://www.triumphspitfire.com/jets.html

Check out the Fiat jet sizing. The Fiat ran a 40 idf with 125 mains and 210 ac jet with 32 vents an F11 ET. Swapping to a 210 ac jet will lean you up a bit more at high rpm.

I personally think you have a combination of fuel delivery and carb issues.

[kenshapiro2002]

I'll do the test later, but since she's fine for a few minutes...even 5-10 and will go close to redline, it sounds (thanks to the education I;m getting from you) like it's more the floats slowing draining down.

Educate me on that. It's a 1.7 with a 1911 big bore kit. I'm assuming the jetting was done back in 1989 when all the work was done. Even if a 1.25 would be an improvement, it certainly isn't my current problem, is it?

Having mains that are too small will cause those same symptoms. You can verify that by idling your engine for a few minutes and then rev the engine up close to redline and hold it there for a few seconds. Try it unloaded and loaded. If you get a lean pop you can be pretty sure your not getting enough fuel from your mains. Holding it at high RPM for a few seconds takes the accel pumps out of the equation. They can mask small mains if you don't hold it there for a bit. Just be sure to let it idle for a minute before you do the test. Starvation due to fuel delivery problems takes longer to happen because you need to draw down the float bowls to make it happen. If you get no pop in the test your mains aren't the issue.

Look hear: http://www.triumphspitfire.com/jets.html

Check out the Fiat jet sizing. The Fiat ran a 40 idf with 125 mains and 210 ac jet with 32 vents an F11 ET. Swapping to a 210 ac jet will lean you up a bit more at high rpm.

I personally think you have a combination of fuel delivery and carb issues.

[kenshapiro2002]

Alright...went out to do the "test". I idled her for 3-4 minutes. As I apply throttle, she starts to break up, pop and backfire (seems to be carbs and exhaust) at around 3,000 RPM, and seem to want to freeze at 3,000 or so, and even start to lose RPM. If I just keep punching her further, she seems to get beyond that behavior and rev right on up close to redline where I can hold her for a good bit of time. This is the same as when I drive her...she starts to "eff up" around 3,000-3,500 RPM, and if I just force her , she goes beyond that up to redline.

[jmill]

Transition issues. What size idle jet? Check your float level and bump up your mains.

You are getting a lean transition when you go from idle jet to main jet. You need to make sure your float level isn't low. After that try bumping up your main jet to 125 or 130.

Having a low float level delays when you come on the main jets. Then you pop at @ 3K. If your float level is good bump up your main jets. I personally think they are too small. I'd go with 130's and then go smaller from there. It'll run ok if they're a bit too big. It pops and stutters or you burn up stuff if they're a bit too small.

[kenshapiro2002]

I'll check the idle jets in awhile and post it. How do I check the float level (11mm) without redoing the gasket, etc.? Can the low float level be because of the sock being blocked or not. What did you think about the photo of the sock and surrounding area? Normal stuff?

Transition issues. What size idle jet? Check your float level and bump up your mains.

You are getting a lean transition when you go from idle jet to main jet. You need to make sure your float level isn't low. After that try bumping up your main jet to 125 or 130.

Having a low float level delays when you come on the main jets. Then you pop at @ 3K. If your float level is good bump up your main jets. I personally think they are too small. I'd go with 130's and then go smaller from there. It'll run ok if they're a bit too big. It pops and stutters or you burn up stuff if they're a bit too small.

[cwpeden]

I also had stavation and stalling, mind you it was on a 2.0 with FI, but this is the strainer compared to a new one. Not a problem since. $8.

Check my post:
http://www.914world.com/bbs2/index.php?act...t&p=1045406

[jmill]

Changing the sock and fuel line is a good idea. I'd even change out your fuel pump. Unfortunately, thats not your problem. You can't adjust float level without cracking the carb open. You can assume it's fine and go with larger mains and see what happens. You'll be out the cost of the jets if that wasn't your problem. You will have gotten away with not cracking open the carb if it was. I do have to say a lot of guys with lean transition issues seem to be running a 115 main and a F11 ET. Thats what comes in the 40 when they come from Weber. I always wondered why when IMHO the 125 was the more suitable jet. I guess it's so they can sell you more jets.