@7900_Blazer You have already gotten some great responses but I'll give mine. I'm going to go though your questions one by one, and I'll put my answers in italics.
I few questions/thoughts from this experience:
- At operating temp, my engine coolant is roughly 210 degrees... won't gas with ethanol simple turn to vapor at that temp - requiring moving from a mechanical pump to an electric pump?
No, first of all that's coolant temp and you want the fuel to vaporize as it enters the combustion chamber anyway. I recently drove my square in 110F with a load uphill, down hill on the highway and in traffic, about 100 miles in all. I'm running a mechanical pump with factory return and it never once even tried to vapor lock nor did it act any different from any other day. The only way you'll know for sure is to check the temp of the fuel pump and lines with an IR temp gun, you can get one for like $20 at harbor freight and it'll save you from guessing. Anything below 220 coolant temp is considered normal, and often in traffic the fan clutch won't keep it much below 210 - 220F
- I'm NOT excited about relying on an Edelbrock electric fuel pump: one with many reviewers having experienced their lack of build quality/reliability - are there better 'carbureted' electronic fuel pumps you all use?
At the shop I strongly discourage everyone from going to electric fuel pumps unless they have a good reason like on a carbureted vortec motor. I don't think there is any electric pump, with the exception of modern FI cars, that can even remotely compete with a mechanical pump in terms of reliability.
- I was convinced the pop-tart wrapper was the problem... but learned differently when my Blazer got up to operating temperature (and I was again on the side of the road)
Good to know, but I'd still encourage you to do a temp check on the lines / pump. Also it is not hard to add a return line to a non-return system, or to verify that the return system is functional if it has one in order to keep the mechanical pump.
- Am I left with the fact that all 'modern' (ethanol) fuel has a lower boiling point (turning from liquid to vapor), so having a pump NOT bolted to the side of the motor is the new normal?
No, as I said earlier I'm still rockin a mechanical pump, as are many others. I'd say switching to electrical is uncommon just for vapor locking in an otherwise mostly stock setup. Keep in mind while you are talking about gasoline it's not just ethanol and gas mixed up, it's complex compounds and additives. I have heard it said that gas boils easier than it use to but it's all word of mouth and I've seen zero proof of that. Also only 10% of pump gas is ethanol. Think about it, it's 90% the gas. I don't think that ethanol is to blame. Prove it by filling up at an ethanol free station, often found at farm supply stations as well as others.
- Is there a realistic option to get the operating temperature of my motor down to say 180, and with minimal pressure, never see a vapor lock issue?
You can install a cooler thermostat, if it's got a 195 go 180, if it's got a 180 go 160, but again it has more to do with exhaust temps, which is right next to the pump and lines. I just went rounds with a guy that has a 55 bel air, he had a 195 stat and was getting some mild vapor locking. One of his friends told him a lower temp t-stat would fix it and he wanted a 160, I told him it would not fix his vapor locking, and it didn't. What did fix it was shortening up the rubber line from the frame to the pump. Someone had replaced them in the past used way to much rubber hose and loop it towards the exhaust manifold. I'm not saying there isn't a chance cooler temp T-stat won't help, I'm just saying I haven't seen it help.... Ever.
- I don't understand why I've never had this happen in Texas...
could be the gas. There are lots of additives in gas we have just made a big deal out of the ethanol. Remember lead how about MMT, both were well known additives blended in. There are also additives blended into the mix to increase the boiling point, and they maybe different from place to place and season to season. Also as you said a lot more big hills, you step on the gas hold it there and those manifolds may get hotter then when your cruising in Texas.
- I don't understand why in Colorado Springs, running off the gas can in the floorboard got me going again...
The wrapper in the tank maybe? Maybe it's not vapor lock. We have all through out other ideas so I won't rehash.
- If you say 'the gas coming from the gas can in the floorboard was cooler than the pre-heated gas running through the factory lines down the frame'.. my response would be: 'then why did it still vapor lock when I ran a new rubber line outside the frame rail away from the heat? - I would add that the mechanical fuel pump was the same temperature as the block... so any fuel entering it would turn to vapor..
Seems to me this makes it even less likely to be vapor lock, but vapor locking can be tricky sometimes. Black rubber line is good at absorbing heat so if it was close to the exhaust manifold before you got it to the outside of the frame rail, or for some reason that manifold is getting hot than it should be, but then we'd circle back around to why did it not with the can on the floor. Was this before or after the wrapper was found?
- My wife's GMC Yukon has 360k... and she'd driving it around the mountains like it's brand new... I've tried to upgrade it for her but she won't budge until she hits 400k.... never touched the electronic fuel pump inside the tank... so how do I replicate that reliability? - Go to EFI?
Fix the current problem and move on when or if you nail it down without modifying the factory system we'll all go ah, so that was it! Yes you could go EFI that would solve it but how much you want to spend on a good EFI system? a couple grand, more maybe?!
-To say the least, I'm pretty bummed about the future prospects of just running an old stock Chevy...
It sucks right now I know, I've been there. I was 1,000 miles away from home and punched a 2 foot hole in the gas tank of an Oldsmobile I use to own. Brought it home with a rented truck and trailer, adding that, missed work and cost to repair I was in it way more than the car was worth, and at the time I thought I should have left it in California and driven a rental home, it would have been cheaper. But in the end I enjoyed many more trips in that car. Or the time I was across the country and had reverse go out in another rig. Most of us could probably share breakdown horror stories. The most important thing is to be as prepared as possible, no matter the age of the vehicle keep maintenance up to date, and know that driving a new to you used vehicle of any age could hold weaknesses you don't know about yet. Even still issues occur. Roll with it as best you can and enjoy the rest of your trip, next time you'll have these issues ironed out!
