Captain Obvious

boosd, SteveJ summed up the problem when he said that the Green/White wire is somewhere shorted to the Red/Blue wire. Problem is figuring out where that short is. Here's one idea that might help track it down: Park the car in a dark spot (dark garage or just wait until it's dark out). Turn the dimmer control to full dim. Turn the combo switch to the first position (turn on the parking lights). The parking lights should all be lit and the fuse should not be glowing. Then quickly turn the dimmer to full bright and look at your interior illumination lamps. Don't keep the dimmer full bright for long because you're going to pop the fuse or burn something up again. But quickly look at the following: speedo tach water/oil amp/fuel clock lighter heater control panel radio hazard sw If you can't look check all of them in a second or two, just turn the dimmer back to full dim and give it a minute or two for everything to cool off. After a cool off period, do it again to check the stuff you didn't check the first time. If any of those devices are NOT lit, I'd start there.

Steve, Haha. Yeah, that's one of the things that gives me trouble with distance diagnosis. That and the ability to explain things in a way that others understand. It might make sense in my head, but being able to convey that info without writing a novel is a different story! I found the same thing as you did with the buried splices. I'm planning some electrical upgrades (like headlight and starter relays) and have dissected a cadaver engine compartment harness for investigation. They did the same thing there. Splices crimped and taped and then buried in the outer layer of tape. Just hoping the fault isn't buried...

Yup. That's what I'm thinking. The thing that worries me the most though is that all of this started after some melties happening. I just hope it isn't melted insulation buried down in the harness somewhere. If it's a bulb, even I could probably find it. However, if it's melted and shorted insulation somewhere in the harness, I'd need one of those RF signal sniffers.

Maybe it's just me, but I'd much rather have that 280 than that series 1 barn find (maybe hit in front maybe not?) that's on ebay for stupid money. That 280 is fantastic. I still don't think I'd pay 25K for it, but it sure is beautiful.

The pot doesn't go OFF-ON instead of gradual. He's got a very low resistance connection somewhere between the output of the pot and ground. That connection is sinking away most of the current through the pot and only a small amount goes through the illumination bulbs because their resistance is higher than whatever is shorted. (Think voltage or current divider between the short and everything else.) So when the pot is cranked to full brightness, there's just enough current through the bulbs to get some light out of them even though the improper connection is sucking down most of it. But when you start cranking the pot away from full brightness, the current drops and the bulbs go dim. Bulbs are still passing the same percentage of the total current, but it's not enough to glow the filaments. Even with the pot turned a little off full bright there's still lots of current flowing through the pot (too much in fact), but not enough to glow the filaments or blow the fuse. At least that's my read... Electrical troubleshooting is very hard from afar!

I don't think it has anything to do with the parking lights. He said he disconnected all of them and the problem persisted. He also said that he can crank the dimmer all the way down and the fuse doesn't pop. It's got to be something powered by the dimmer rheostat.

Not sure what's going on, but tossing out some stuff to think about. How do you get a continual rich condition? - Nozzles not adjusted properly - Shouldn't be rich at 2 turns down (assuming nothing is worn out). - Float level too high - You checked this and it's OK - Float needle being overpowered by the fuel pump - You got a 3 psi regulator - Nozzles getting stuck down instead of returning fully up - You checked this and it's OK - Needles not installed correctly in the pistons - You checked this and it's OK - Pistons getting stuck and not rising properly - You checked this and it's OK How do you get a transient rich condition upon startup? - On a hot shutdown, you boil the fuel in the bowl and as it percolates, it bubbles up past the needle and into the carb throat and then runs into the intake manifold. - After you shut down, you slowly overpower a slightly leaking needle valve(s) with residual fuel pressure in the rail. The pressure in the stock rail and pump system drops to zero when the engine stops, but with your electric pump and a regulator, I don't know how you have it plumbed. If you're applying three PSI to the needle valves even when the engine is off, you might have a small leak in one or more of the needles that isn't a big problem when the engine is running and consuming gas, but might be an issue when the engine is off.

Very nice! Are you gonna rattle can the block or you got more elaborate plans for that?

The problem is in the dash illumination light section, but it's not the dimmer switch, it's somewhere else. Something in your illumination lamp section went almost short and is hogging current. It's not a dead short, but almost. It's not the dimmer itself. It's not the parking lights. Maybe one of your illumination bulbs in one of your gauges failed short? Could also be the illumination bulb in the hazard switch or the heater face. Maybe ash tray lamp (if you have one - not sure when they added that). I'm thinking that either one of your small illumination bulbs went short or you pinched or melted a wire somewhere behind the dash. Was everything working fine before you burned up (and then replaced) the first combo switch?

Excellent. Either a little tighter on the current banjo washers or going back to the old washers then. Even though the bowl gasket has been cleared of issues, I do have one more thought about that part... I was originally thinking the same thing, and that's why I asked the question. But after I asked the question I started thinking that it probably wouldn't really matter. The fuel level may be below the level of the bowl gasket when sitting static in the garage, but as soon as you hit the road and the fuel in the bowl starts sloshing around, that gasket is going to be completely bathed with fuel pretty much all of the time even if the bowl level is correct. So the bowl gasket has to be a positive seal even if the fuel level is correctly below the level of the gasket. In other words, you can't get away with a poor bowl gasket even if the fuel level is at spec.

If you did the float level on the car I have confidence in the results. I've never experienced the bowl gaskets leaking with new gaskets. They always seemed to do a good job of sealing. I guess it's possible that there is some flaw in the bowl lip or cap sealing surface that the old gasket was able to compensate for, that for some reason, the new gasket cannot? I have seen the banjo washers leak though. I solved that problem by simply loosening them up a little and then cinching them up again (maybe a little tighter than they were last time?). Failing that, you could try reusing the old metal washers. I wonder if maybe what you think is a leaking bowl gasket is actually fuel spreading from the banjo bolts and the bowl gaskets are not really leaking? Gas, being thin and volatile, spreads rapidly...

Did you do the clear line check on or off the car? If you did it off, I would recheck it on the car. You used new bowl gaskets and banjo washers?

Happy Thanksgiving to the Great White North!!

That's so cool! I did some distance learning from the same institute. I've got my Sheet Harbour Institute of Technology Hardware Engineer Associates Degree.

It does sound lean to me too, but before you start turning knobs and stuff... It ran fine yesterday without any of this behavior? The dead spot off idle didn't start until today?

Only word of advice on the engine build... I'm sure you already know this (and I would consider it "common sense"), but make double dog sure that you get every last molecule of blast media out of the engine internals before you assemble. I'm sure you already knew that but the only reason I'm mentioning it is that it's easier said than done. All those nooks and crannies where sheets are spot welded together and stuff? Up on the blind underside of the oil pan baffles? Inside the PCV separator? That sort of thing. And thanks for the photo tips!

They call those "oval heads", I think they look fine. As for coloring them black... SHARPIE!!! It won't last forever, but when it rubs off from the stuff swimming around inside the console, just hit them again. Once a year maybe?

You are really good with the camera. My pics always seem to come out so utilitarian... Useful and descriptive, but bland.

I like that movie. I don't think I ever saw it uncut though. I've only ever seen it on regular TV so I'm sure there are parts I've never seen. It was fun hunting for a Z. Thanks Julio!

That's what I was thinking as well, but I'm not sure if that's the car Julio was talking about. He said Constantine was walking across the top of a row of cars and that happens later in the scene. But this car (that you and I think looks like a spitfire?) is the only thing I saw that looked even remotely like a Z. I'm not sure if that's the car he meant.

"God I hate this part..." Everything is on youtube! Is this the car you're talking about? I'm thinking it looks maybe more like a Triumph?

Wait a minute... You're saying that part number (that sells for new from a dealer for $1700) is actually for a matched PAIR of front and rear carbs? If that's the case, then $1600 for the pair on ebay is not a good deal. I was thinking that was each, not a pair, but I do see what you're saying with the parts breakdown.

I don't think you're missing anything. The carbs on ebay are a pair of both front and rear stuffed into one box. I didn't check into the P/N to figure out if the box is front or rear, but the point is that $1600 is a little less than half price for the pair. No guarantee and no returns if there's a problem, but if you just gotta have new, it's not a bad price.

Those sure are pretty. I'd feel guilty about putting fuel into them for the first time. They'll probably end up on a show car, not a driver. You better have the entire rest of the engine looking new before you slap those things on.

I was figuring with that much play at the wheel, it should be pretty easy to spot? I've been waiting for the outcome.