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The 2wd burb thread. Fixed!!!!

2wd big block burb tow rig
I'd test that purge valve. They can cause lot's of funky fuel tank issues. Focuses had a recall for purge valves that wouldn't vent and over pressurize the tank and pop it at the seams...
 
The one thing about fuel boiling off is it didn't do it the whole way home from Seattle, nor did it do it on the first part of this trip. But a full exhaust has certainly moved up my priority list.

@Z71paramedic it does have a purge valve apparently.

It was working harder on the return trip, no? :thinking:
 
Naw just my head.

Trip report. Afton Wyoming to Chicago and back in a 1989 Suburban!

It was great. Burb had a couple issues that I wanna talk about but this thing is really pleasant to drive.

So biggest issues were I at some point started pressurizing the gas tank. Enough to kill it at idle and once enough to not allow fuel in it for nearly 20 minutes.

Like I said my head has been bad ( big trips do that to me) so I haven't checked much but I was told a plugged charcoal canister can do this. I sprayed the lines going from the tbi to the charcoal canister out and it seemed to help but my milage dropped at least a 1 mpg.

So symptoms are pressurized fuel tank and a mileage drop.

What should I check?

When I got stranded a few years ago it was because the exhaust pressurized the gas tank. This in turn pressurized the charcoal canister and barfed coal into the carb which locked the float down, making it puke gas everywhere up top.

I don't know if you have the time but if you do, split the carb to see what it looks like inside. Also if you pull the line going to the carb from the canister and it pukes, good chance it may have blown charcoal into the carb.
 
Sure sounds like gas boiling off from hot exhaust. Both the stalling and the pressurized tank. And especially the 15-minute time delay.

I don't think the tiny canister can provide enough pressurized air/vapor to vent for 5 minutes straight. It's a tiny thing.

@ZooMad75, does that sound right?

Could be fuel boiling. But Like Eric said it didn't do it on the way back from where it came from. That's not to say the pump might be giving up the ghost. It may have more to do with the pump just getting hot on long runs. I'd be curious if the timing to the problem is just that, long highway runs and low fuel level. If the pump is drawing more current it will run hot. Lower tank levels limits the amount of cooling effect the pump has by being immersed in the fuel, so again it tends to run hotter. Combine both together and it could be enough that the pump just quits and won't restart until it cools off. Keep this in mind, this senario won't cause the pressure build up in the tank.
 
The worst it did it I had stopped to get fuel, level was a 1/4 tank. The previous tank where it had only done it slightly was nearly empty. But I started not letting it drop below half a tank. At that point I had left the gas cap loose so I can't really say

All of these were extended highway runs. I kept it under 70, mostly in between 60 and 65.
 
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Well, all problems aside....... How did it pull? :popcorn:
 
Well, all problems aside....... How did it pull? :popcorn:


I need overdrive lol. It pulled great. Slows down on some hills but on the trip back with the weird problems I was having I did everything I could to stay in 3rd and be gentle. Slowest I got was just south of my house. About 40 on a mile and a half 7% grade.

All in all it pulled great. Very solid tow rig.
 
The worst it did it I had stopped to get fuel, level was a 1/4 tank. The previous tank where it had only done it slightly was nearly empty. But I started not letting it drop below half a tank. At that point I had left the gas cap loose so I can't really say

All of these were extended highway runs. I kept it under 70, mostly in between 60 and 65.

It really could be either issue. I'd be less inclined to think it's exhaust routing causing hot fuel to overheat the pump, but I don't remember what your exhaust routing is. If you kept the fuel level above 1/2 and it didn't re-occur it may be a weak pump getting hot.
 
It really could be either issue. I'd be less inclined to think it's exhaust routing causing hot fuel to overheat the pump, but I don't remember what your exhaust routing is. If you kept the fuel level above 1/2 and it didn't re-occur it may be a weak pump getting hot.

No pipe directly after the cat. So it's quite a distance from the fuel tank.
 
No pipe directly after the cat. So it's quite a distance from the fuel tank.
Well that's on the opposite side from the fuel lines in the first place so that pretty much kills the idea of the exhaust heating up the fuel. Could still have the pump drawing higher current and running hotter.
 
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Well no issues as of late.

Cept one. I need a muffler and either some serious welding, a new exhaust manifold, or headers.

What muffler are you guys using that is quite, and is there an aftermarket exhaust that isn't a dual exhaust?
 
I run flowmaster 40’s but they aren’t exactly quiet. The guy I work with runs 50’s and they sound pretty good.
 
Well no issues as of late.

Cept one. I need a muffler and either some serious welding, a new exhaust manifold, or headers.

What muffler are you guys using that is quite, and is there an aftermarket exhaust that isn't a dual exhaust?
If you run both into one it’s not bad, even with a “flowmaster”
Magnaflow comes up a lot, or dynomax super turbos , both are quieter
 
I love my manga flow sound, we had a flow 50 on our bbc burb and it was great as well. Much more mellow and grumbles with no drone down the highway.
 
I'll second the Magnaflow, I recently put one on the Trazer. Pretty mellow at idle and cruising, but pretty decent once you get on it.
 
I have a dual chamber, single in dual out flowmaster on my Z28. No cat. Has a nice purr at idle, a strong resonance in the mid range, but nothing too loud
 
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