Whoever said that pushrod V8s are simple can GTFAC

"The Swedish Bandit" (swedishbandit) 09/03/2013 at 16:51 • Filed to: joy

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Okay let me update you with a follow-up to !!!error: Indecipherable SUB-paragraph formatting!!! . After taking Joy for a spin earlier today, it became obvious to me that the carb swap did nothing to improve the situation. I'm still getting the exact same symptoms as before, which are fuel starvation after it gets hot and flooding of the carb after you let it cool down a bit, (but not completely.)

!!! UNKNOWN CONTENT TYPE !!!

Now, !!!error: Indecipherable SUB-paragraph formatting!!! suggested that it might be a bad fuel pump, so you now what I did?! I fucking bought a new pump, just like that! Aaaaaand it didn't help at all... FUCK! (absolutely don't blame matt in any way for my wrongly spent 40$, it was a very plausible cause)

Okay so here's the scenario; there's something wrong with the fuel system, which keeps fuel from reaching the carb and sometimes also floods the carb. The engine only works good a couple of minutes when cold. Now from what I concluded; it ain't the carb, it ain't the pump, it ain't the fuel filter or the fuel lines, so what the hell is it?! I' am seriously loosing my mind here! The only thing I can think of is that the return line from the pump has been plugged. Maybe it is possible that it causes too much pressure in it or something. Any thoughts?

Help me Oppo. You're my only hope!

PS9 > The Swedish Bandit 09/03/2013 at 16:54

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Check the filter and lines?

The Swedish Bandit > PS9 09/03/2013 at 16:57

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Checked them twice and have blown them clean with compressed air. And the fuel filter is fairly new so it shouldn't be a problem.

Nibbles > The Swedish Bandit 09/03/2013 at 17:00

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I think you're on the right track checking out the fuel return system.

Sparf > The Swedish Bandit 09/03/2013 at 17:00

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Since I can't be very helpful, I'm going to go ahead and whine about the emptiness here.

*Whines*

Bandit > The Swedish Bandit 09/03/2013 at 17:02

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Still no clue. No idea if this would be related, but, is your car running hot enough to boil the fuel in the lines/filter area?

RamblinRover Luxury-Yacht > The Swedish Bandit 09/03/2013 at 17:03

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The only thing I've ever run into like this was on small engine equipment with fuel tanks not breathing. Running until a vacuum was built up in the tank then quitting, and then on the shortly-thereafter continuing to warm (close exhaust to fuel tank, etc.), building gas tank pressure enough to force-feed a little extra fuel after it had caught up. Or, in some cases with string trimmers, having a clogged pickup screen in the tank and having a system to pressurize the tank - more air being put in than fuel taken out, but when sitting, the pressure forcing fuel into the throat.

Probably not anything like that, but if you have a primitive first-gen tank vapor control setup, who knows.

WarShrike > The Swedish Bandit 09/03/2013 at 17:03

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I'm thinking vapor lock somehow. If you say it is flooding when cold, are you sure? Pull the spark plug after it dies to make sure it is a wet plug or dry.
Do you have aftermarket headers/exhaust system?
Are the fuel lines running close to the exhaust? That could be one problem there.

That's about all I can think of, I'm an EFI kiddo lol!

The Swedish Bandit > Nibbles 09/03/2013 at 17:06

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Yeah, but the annoying part is that I gotta make a new fuel line that runs under the car and back into the tank, since I threw the old one away to save weight. Stupid racecar physics...

Audio Tachometer > The Swedish Bandit 09/03/2013 at 17:06

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Check the float levels? I've seen new in box carbs with floats set in the absolute bottom of the bowl. Check for vacuum leaks. Also, at least do a cursory ignition check. You know the old saying, 90% of carb problems aren't the carb...

Union of Smog Techs of CA > The Swedish Bandit 09/03/2013 at 17:08

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Stop guessing and use your brain. Don't throw parts at cars without diagnosing. A carb needs many adjustments to work right. Are you setting the float, etc, etc?

desertdog5051 > The Swedish Bandit 09/03/2013 at 17:14

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Since it has a carb, and is not fuel injected, there should not be a fuel return system. I would check fuel line pressure first. Generally 6-10 psi on a carbureted motor. Possibly ignition coil not working properly/weak. That can have symptoms similar to what you describe.

Pearson Hurst > The Swedish Bandit 09/03/2013 at 17:15

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I agree with checking the return line and FPR (assuming you have one, since you have a fuel return line) I'd also check that the choke is functioning properly, as that would account for running OK when cold, and like crap when it's hot. It definitely doesn't account for flooding after it's off though. As mentioned, I'd check the float level and the float itself as well as the needle and seat, as they should prevent more fuel from entering the bowl once the float rises. Easy way to check that there's no vacuum forming in the tank would be to drive with the gas cap loose and see if it makes any difference. It's worth double checking the ignition system as well, since things like ignition modules and condensers can definitely act up only when they're hot.

The Swedish Bandit > RamblinRover Luxury-Yacht 09/03/2013 at 17:15

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Forgot to mention that I'm running with a 10 gallon boat tank in the trunk. Always keep it on full ventilation and it has worked brilliantly for 2-3 months now so I don't think that's the problem. And the exhaust and headers is nowhere near the tank or any fuel lines so there shouldn't be any heat issues with the fuel... or now that I think of it, the fuel line from the pump up to the carb sits pretty close to the engine block, which can get very hot. Maybe something to go on?

The Swedish Bandit > WarShrike 09/03/2013 at 17:16

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Forgot to mention that I'm running with a 10 gallon boat tank in the trunk. Always keep it on full ventilation and it has worked brilliantly for 2-3 months now so I don't think that's the problem. And the exhaust and headers is nowhere near the tank or any fuel lines so there shouldn't be any heat issues with the fuel... or now that I think of it, the fuel line from the pump up to the carb sits pretty close to the engine block, which can get very hot. Maybe something to go on?

Frank Grimes > The Swedish Bandit 09/03/2013 at 17:19

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Vaporlock?

The Swedish Bandit > desertdog5051 09/03/2013 at 17:22

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Well now there is (was) a fuel return system, so I'm thinking it might have something to do about it.

I've checked the ignition right after it dies, and it generates a very bright spark. The problem is that I'm not getting any fuel up to the carb.

Anyways, will do a basic pressure test first thing tomorrow.

Pearson Hurst > The Swedish Bandit 09/03/2013 at 17:23

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So, you have no fuel return line at all now?

Pearson Hurst > The Swedish Bandit 09/03/2013 at 17:24

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Is the fuel tank higher than the carb by chance?

The Swedish Bandit > Audio Tachometer 09/03/2013 at 17:25

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Ignition has been checked. And I went over most of the Holley before giving up and switching to the old q-jet. Both carbs have worked very good in the past so I don't see why they both should stop at the same time.

The Swedish Bandit > Pearson Hurst 09/03/2013 at 17:26

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Nope. Nothing.

Pearson Hurst > The Swedish Bandit 09/03/2013 at 17:27

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Was it running properly that way?

WarShrike > The Swedish Bandit 09/03/2013 at 17:28

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Maybe wrap it in some insulation/heat shielding?

The Swedish Bandit > Pearson Hurst 09/03/2013 at 17:28

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Hmm I guess they're kind of close in height. The outlet on the tank sits on the top of it, and I guess that would "almost" be on even height with the carb.

Pearson Hurst > The Swedish Bandit 09/03/2013 at 17:31

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I was mostly wondering if the fuel level in the tank were higher than the carb. If it were, you might reasonably expect fuel to continue flowing to the carb even with the pump off due to a siphon.

The Swedish Bandit > Pearson Hurst 09/03/2013 at 17:33

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When I bought the car the fuel return from the pump was plugged but the line was still attached. The car ran fine that way so I figured that having a rusty fuel line under the car would just be a waste space. The Swedish vehicle inspection also doesn't pass any cars with rusty metal lines on them, which was mostly the cause of removing it.

The Swedish Bandit > Pearson Hurst 09/03/2013 at 17:35

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Ahh okay then, but no I've got freeflow to just after the fuel filter, which sits under the car prior to the pump. The flooding only occurs as long as I mash the starter.

The Swedish Bandit > WarShrike 09/03/2013 at 17:37

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Definitely an option, and all options are good at this point. Thanks!

The Swedish Bandit > Pearson Hurst 09/03/2013 at 17:43

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As I mentioned to someone else the carb(s) have been ruled out completely. I've probably checked the ignition system 3 times already and I have also reheated the plugs with a torch to burn of all the oil deposits that we're on them.

Driving with the gas cap of? Sure why not!, though I highly doubt it would fix anything.

The Swedish Bandit > Union of Smog Techs of CA 09/03/2013 at 17:47

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I've diagnosed this problem for probably 5 days now and after doing a complete oversee of my main carb and also testing my spare one, I felt that I needed to try something and the fuel pump was the most likely candidate.

The Swedish Bandit > Sparf 09/03/2013 at 17:50

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Yeah I'm thinking about rounding of the edges just a tad bit and maybe also implementing some kind of bumper. Not something big, just a small square metal rod that goes underneath the lights and the continuous to curve around the corners of the body.

What do ya think about that?

GasolineLollipop > The Swedish Bandit 09/03/2013 at 18:14

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Electric or mechanical fuel pump? What are the outside temps? Has that changed since your problems arose?

Union of Smog Techs of CA > The Swedish Bandit 09/03/2013 at 18:15

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I always worked better when my friend turned boss said "What the fuck are you doing? Fucking ass, USE BRAIN!" with an Indian accent.
I'd ask you where your fuel pressure gauge is but I lost mine so I can understand if you don't have one.

GasolineLollipop > GasolineLollipop 09/03/2013 at 18:15

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What do you mean by flooding of the carb? Hard start? If the engine is hot it doesn't need much fuel to start.

Sparf > The Swedish Bandit 09/03/2013 at 18:16

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How about the original article?

The Swedish Bandit > GasolineLollipop 09/03/2013 at 18:19

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Mechanical. If by outside temps you mean the weather, than yes, it's gotten a lot colder. When I completed the build it was in the beginning of summer and pretty hot. Now though, it's more like 15-20 degrees Celsius (which in American units I think means something like; too cold to just wear a t-shirt but too hot to wear a sweater over it).

GasolineLollipop > The Swedish Bandit 09/03/2013 at 18:25

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I haven't experience vaporlock when its cool out. You are describing fall weather here in Texas, which the car should be running pretty good. You should be changing the jet sizes around now to a richer setting. What do the plugs look like?

Is the flooding visible? Are you describing the hard start condition?

The Swedish Bandit > Sparf 09/03/2013 at 18:28

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Well, uh I like the taillights of mine better, and they don't really work with that bumper (which by the way is huge and goes "in" in to the metal sevreal inches).

Oh and there is also the problem with the twin exhausts.

Though I'm thinking about buying a set of original quarter panels and then shape the rear according to them.

The Swedish Bandit > GasolineLollipop 09/03/2013 at 18:37

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Before it all went really bad, the carb was running way to rich so I went down a couple of jet sizes which made things better. For a while....

Plugs are only a couple of months old but due to all the issues I've had they have become flooded with gas a bit too much. But I torched them clean the other day and now they seem to be in a good condition.

The flood is definitely visible. Just after it has died, it is impossible to start due to no fuel, but if it's been siting for a while, a quick double pump always makes it fire right up.

GasolineLollipop > The Swedish Bandit 09/03/2013 at 18:40

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Will it die just idling?

The Swedish Bandit > GasolineLollipop 09/03/2013 at 18:44

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Right after it's been fired up I've gotta give it some gas to stay alive, due to not having any choke. But after it's been heated up it idles very nicely. Also it doesn't seem like the fuel starvation can happen on idling. I've had it running hot on idle for 10 minutes and it has worked brilliantly, but if I hold the throttle at half speed for just 20 seconds, it dies.

Sparf > The Swedish Bandit 09/03/2013 at 18:56

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How important is that pressed-together twin exhaust to you stylistically? I'd personally go with something like this if you're not going with the metal bumper and are going to keep the taillights:

AKA stock but with a nicer exhaust (albeit still tilted downwards).

GasolineLollipop > The Swedish Bandit 09/03/2013 at 19:03

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I don't know. You need to see what's happening to the fuel pressure at the event. You also need to check the plugs when it dies. Its something simple you are overlooking. These cars only get complicated when you overthink them. Swapping the carbs and still having the same issue can rule out the carbs (small chance the same problem lies with both carbs). The description of the event, No fuel then tons of fuel, sounds like a fuel boiling condition or a tank not vented properly. Make sure your fuel line return from the pump is fed back to the tank. Good Luck

The Swedish Bandit > Sparf 09/03/2013 at 19:05

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I still have the stock bumper and I could just cut it up and make a frame on it that goes around the exhausts. The thing is, I think it "judges" out of the body way too much and the fact that it cuts in to the quarter panels.

The setup I'm running now is really lightweight + that it has a secret moonshine stash under the taillights since it's hollow. With a few more adjustments as previously mentioned, I think it will look absolutely killer.

The Swedish Bandit > GasolineLollipop 09/03/2013 at 19:09

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Thanks! As it looks right now the things to do are; check the fuel pressure, make absolutely sure that the fuel isn't boiling anywhere and making a fuel return line to the tank. I'll make sure to do an update when I get it straightened out.

GasolineLollipop > The Swedish Bandit 09/03/2013 at 19:28

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Replace the fuel filter while you are at it.