quote:

Originally posted by ccctimtation:
I installed mine with a momentary switch for starting. During run it is held in with the oil pressure switch.

Hooked up thru a 5 pole relay correct?

Speaking of; for a galvanic isolator I used a 12VDC energized DPDT 15amp relay and run both neutral and hot to supply and switched sides. I think the Radio Shack bill was under $20 versus closer to $100 for the galvanic isolator.
ccc doesn't always mean cheap cheap cheap but sometimes

On mine, I used my OEM "aux start circuit" as a power source for bypassing the oil pressure switches. This serves several functions:

1. The beauty of the original Barth instrument panel is not sullied by a Chinese switch.

2. The expense of a Chinese switch is avoided.

2. The doubtful reliability of a Chinese switch is avoided.

4. The complexity and expense of a relay is avoided

5. The doubtful reliability of a Chinese relay is avoided.

6. It is a decent anti-theft measure. The thief gets only as far as the fuel in the float bowl will take him.

7. If the oil pressure switch fails (and they do ) it easier to drive with the aux start switch energized than holding a button.

I should add that I replaced the OEM momentary on switch with an ON OFF MOM switch long ago after an alternator failure forced me to drive holding in the aux start switch to allow driving while the genset charged the chassis battery.

I'm stuck in Franklin, KY now. Same old same old. I almost caused an accident on I65 because I was only doing 45mph up a hill.

I've looked at a couple other forums about other vehicles just for kicks, not that the advice I'm getting here isn't good. I want to run some ideas past you though.

I'm leaning towards vapor lock. Now I tried driving with the gas cap off. I tried the clothes pins and foil to some degree all to no avail. What if I were just to re-route the fuel line coming out of the pump? Move it further from the engine? Possibly sleeve it with something as well like billh suggested. Or could I install another filter between the pump and carb with a return outlet on it and tie that into the existing return line?

I've got yet another mechanic looking at it now. He adjusted the timing slightly and moved a hot wire that might have been grounding out on the Magnetic Switch(I didn't know what it was either until I read that other thread). I took it for a drive and it still did the same old BS so I took it back.

If it's vapor lock there are several possible remedies/tests.

1) Put a space plate under the carb to raise it off the manifold
2) Shield any incoming fuel lines from heat
3) A cool can filled with ice to test the theory
4) A cold air intake, like in NASCAR for the brakes directed at the carb fuel intake area

quote:

4) A cold air intake, like in NASCAR for the brakes directed at the carb fuel intake area

This is one of the things I'm doing to totally eliminate the VL. Wrapping and shielding has gotten rid of 90 0/0 of it but I still get lttle burps when I let it idle too long then get on the throttle.

What did you wrap it with?

Also, a different mechanic told me that I should just plug the return line at the pump. It was just stealing needed pressure. ???

B&H!
Triage: I don't know what your concerns are for time and money, but there generally isn't enough of either for me.

I am guessing the various mechanics you've gone to haven't each had enough time to perform a triage of the situation.

They've each done the best job possible given their hunch and how they interpret what you've told them.

But you're getting a bit further down the road, not solving all of the problems, but you might be having some solved.

I would tend to think that if I didn't get vapor lock when running through Arizona and Nevada at 120F (with a rig similar to yours), in conditions that killed my isolator and fridge electrics, that vapor lock is not an issue in your case. I have headers which add more heat to my engine compartment.

I do think that the weak spot in the design after 20 years of operation are found in the distributor, with the coil, HEI module, capacitor, and so forth. I am basing this on my experience with HEI module failures in a 76 Camaro, a 77 Camaro, a 77 Cutlass, an 82 Delta 88, an 84 C10, a 78 C60, and, yes, twice, in my Barth. Fortunately, one failure was in the parking lot of my favorite mechanic, and the other was in my driveway.

From a triage perspective, $90 with Summit Racing will get you a 'blueprinted' distributor with all new components. http://www.summitracing.com/parts/SUM-850001R

At this point, you don't care about the specific isolation of the failure, and an R&R of that, you just want to get rolling reliably.

This isn't to say though that this is the answer, you might still have a fuel problem. If the rubber lines on the top of the fuel tank connecting the steel lines are cracked, you might not get gasoline leaking out, but air leaking in, when running, in conditions of higher fuel demand. I took my tank off to look at what those hoses looked like, and they were not rubber anymore. They were a cracked and brittle solid.

The easy test of this is to supply your fuel pump via a hose running to a gas can. I'm not going to say this is safe, but if you do this in a parking lot, with the transmission in park and your foot on the gas for an hour, keeping the RPMs up at 3000. If this shows that you have no trouble, then it is clear that your ignition stuff is OK, and the fuel delivery is the problem.

Triage: do the cheap and easy things first to rule in or rule out the problems.

Good Luck!
Matt

The mechanic called. He said he put a new ignition module on. It didn't fix the problem so he took it back off. He replaced vacuum lines. That didn't fix it. He doesn't think that's vapor lock either because he choked it when it was losing power and it just stalled. He's going to put a new carb on and see if that works. He said he'll take it back off if that doesn't work. Maybe he's just soaking me for some labor, but I don't have a lot of other options right now.

I went to Summit and looked at all their stuff but couldn't find the tape I used. I know it came fron Summit but I don't know what it was called. It was about 1" wide, very sticky self adhesive, and not cheap. As far as plugging the return at the pump, WHATTHE?? He's about as much of a mechanic as I am a gynechologist, and I can't even spell it!

Did anyone think that there might be an EGR valve hanging open. I had an Astro van that sporadically went into spasms, wouldn't shift right, stalled at low idle. The EGR valve had built up carbon and when it hung it created a massive vacuum leak. Cleaned it and it worked great.

Thermo Tec tape/heat shield is probably the stuff Danny used. They also carry a sleeve or tubing heat shield that could easily slide over the gas line to insulate it without relying on the sticky backing. See web address
http://www.summitracing.com/parts/THE-14005/

Did anyone ever check fuel pressure while the coach was stalling? If it has adequate pressure, you do not have a vapor lock issue.

The Barth rides again!!!

I never had any doubts(hehehe)!

Thanks for all the advice guys. I was at least able to suggest things to the various mechanics I talked to and be aware that they weren't trying to rip me off. I couldn't have done it without your advice.

I'm not 100% that we're out of the woods totally, but I took it for a 30 mile ride and it heated right up. It was almost 90degrees today. No problems.

What he finally did was put on and electric pump and regulator dialed in at 3 1/2 PSI. He wired it to the ingnition and put in a toggle switch too. He ran it to the fuse panel under the dash on the drivers side.

I don't know what the exact problem was, but everything seems to work now. I think that we've ruled out electrical problems at this point though. Must have been vapor lock or just not enough pressure in those big half inch fuel lines. Could've been sucking air like Matt suggested. Maybe later I will try to put sleeving on the fuel lines and such. Right now we just need to make it to Albuquerque.

I'll have to check the paperwork for the electric pump to see how many amps it is drawing. Is this something I need to worry about?

Also, no one commented on my previous questions about what speed I should be driving and what type of fuel is optimal. I'd like to hear some opinions.

IMHO - Regular gas - premium is money wasted. Normal highway speeds are fine, though I'd be uncomfortable above 70. And remember, you're pushing a big, flat box through the air, so the further your foot is in the carburetor, the more gas you're going to burn. Just stay safe & comfortable, & try not to block too much faster traffic. Nothing is more irritating to automobile drivers than a big, slow-moving RV holding up their progress.