Per Danny's Request: This topic was moved from Thinking of purchasing a Barth. I have ??

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Bill, the" thinking of buying" thread has turned into a fuel starvation thread thanks to me, and I was wondering about hijacking it to a thread with that topic, maybe get some more input. Thanks, Danny Z

Ok Danny, good luck.

BTW: If anyone else wants something like this done for another post, I'm just a PM or Email away. It's not hard to do and you might get a better response if it's in it's own thread. Trust me, you're not wasting my time.

Moved Reply:

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Originally posted by Neil T.:
... It had obvious fuel starvation problems right from the beginning. I fought this the whole way back but I found if I kept both fuel tanks full it did OK. ... Tell your husband the fuel starvation problem was a combination of rotted fuel hoses and faulty fuel change over valves. I now have two electric fuel pumps (one for each tank) and all new fuel hoses.

Regarding the fuel starvation problem. My Euro [454 w/ quadrajet] has a small problem that I can't seem to fix. If I lift off the throttle for more than a few seconds, such as at a red light or going down a hill, then accelerate again, after about 4-6 seconds of acceleration she'll sputter and quit for just a second, usually I have enough speed up so she starts back up on her own, but one time I was entering an uphill on-ramp from a rest area and she wouldn't kick back in. Luckily I got her on the shoulder while still rolling and after much cussing and cranking she fired back up. It doesn't seem to matter how full the tanks are or which tank I'm pulling from. This only happens when up to full heat, about 30 to 50 miles in warm weather. This makes me believe it's a temperature issue like vapor lock. I wrapped the fuel line with heat tape from Summit everywhere it was even close to a heat source, but it didn't help much. Still running the old mech pump. Thoughts?

Moved Reply:

Besides what Neil mentioned, it sounds very much like a fuel pump. I had a similar issue with my SOB (Chebby 5.7L with the Quadrajet, on the long climb on I-24 towards Monteagle, although the problem was only evident when hitting the throttle.

I ran on to Clarksville and replaced the pump and fuel filter at an Advance Auto parts store (temp was 108°F). GM pumps don't last much more than 50K miles.

Another possibility (besides the filter) is the coil, especially if you have one on top of the distributor. Slowing down after a run heats the engine compartment, and a bad coil can do that if it gets hot.

There's also the possibility that it's not starvation but a bad carb float or float valve, and it's flooding when the carb's not dishing out the gas.

And check the vent lines and the charcoal cannister - if the cannister gets plugged, the fuel pump can't move the gas, and you will indeed get vapor lock in the suction lines.

Moved Reply:

quote:

Originally posted by Danny Z:
Regarding the fuel starvation problem. My Euro [454 w/ quadrajet] has a small problem that I can't seem to fix. If I lift off the throttle for more than a few seconds, such as at a red light or going down a hill, then accelerate again, after about 4-6 seconds of acceleration she'll sputter and quit for just a second, usually I have enough speed up so she starts back up on her own, but one time I was entering an uphill on-ramp from a rest area and she wouldn't kick back in. Luckily I got her on the shoulder while still rolling and after much cussing and cranking she fired back up. It doesn't seem to matter how full the tanks are or which tank I'm pulling from. This only happens when up to full heat, about 30 to 50 miles in warm weather. This makes me believe it's a temperature issue like vapor lock. I wrapped the fuel line with heat tape from Summit everywhere it was even close to a heat source, but it didn't help much. Still running the old mech pump. Thoughts?

Danny, My Barth had the fuel return system on it. It came with a high volume fuel pump and a return line that returned the excess fuel back to the fuel tank. This requires two fuel change-over valves, one to the pump, one to return fuel to the proper tank and a bunch of fuel hose to leak. My valves were leaking and transferring fuel to the wrong tank and causing a suction leak if one tanks was empty. After messing with this system for a while I ended up just installing two Carter electric fuel pumps, one for each tank and eliminated the return line. I have check valves in front of the each pump so no fuel chance over valve is necessary. The change over switch now just activates the relay to the fuel pumps. The fuel pump relay is grounded through an oil pressure switch for safety, no oil pressure, no fuel. I also replaced the Chester carb with Edelbrock performer series 1411. A personal preference, just bolt it up and forget it. Quadrajet Carbs are good when thay are good but when they are bad they are bad. The carb on my Barth had been replaced with a cheap rebuilt unit. I had no idea what was in it so I went with what I new would work out of the box. With the two fuel pumps I have redundancy in case one pump fails. I can also plumb one of the pumps to the generator if necessary. I would replace all the fuel lines and you could install an electric fuel pump as pusher. This would prevent vapor lock.

Moved Reply:

Going for the cheap fix first, I'm going to replace the mechanical with a new one and see if it takes care of it. If not, I'll go more along the electronic route, in which case I'll need some guidance, thanks for the info.

Moved Reply:

Neil,

I too had fuel system quirks ('78-24'-P30-454). It was discussed at length here awhile ago at:

http://barthmobile.com/eve/forums/a/tpc/f/3631087061/m/5451033022/p/1

At that time, the consensus seemed to be "unique" design by Barth, but if I understand your post correctly, you think it's defective valving?

Your solution certainly makes sense....Might try it myself.

Was your mod with or without engine driven fuel pump?

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I am sure the two valves worked fine when new and could be replaced but the system is overly complicated to me. I think a modern electric pump properly installed is the way to go.
I do not use the mechanical pump. If you remove the fuel return from mechanical pump it will put out too much fuel Volume/pressure and flood the carb. I think they used the fuel return system to stop vapor lock. The electric pump pushes the fuel and keeps it under pressure so you should not have that problem. That is why the electric pump should as close to the fuel tank as possible. When I first started battling this problem I just used the passenger side tank for the drive engine and the left side for the generator. Later I added a cheap transfer pump to transfer fuel from the left tank to the right if needed. This worked good and was simple unless I forgot to turn off the transfer pump and pumped 20 gal of fuel out the overflow of the right tank . Even with a big red light on the dash I forgot about it. Later I added the two Carter pumps.

Moved Reply:

Mine starved after a few moments at heavy throttle, & sometimes bogged when starting off when it was hot. Changing fuel filters solved the problem.

Mine had 2 filters in the fuel line, plus the filter in the Quadrajet. I didn't expect the second filter in the fuel line, & almost missed it. That suggests it's a good idea to chase the fuel line all the way to the tank.

Moved Reply:

quote:

Originally posted by Danny Z:
Going for the cheap fix first, I'm going to replace the mechanical with a new one and see if it takes care of it. If not, I'll go more along the electronic route, in which case I'll need some guidance, thanks for the info.

Dan.
If you haven't allready done it replace all the fuel hoses from the tank to the pump. If you have a crack in the hose the pump will not pump the fuel, it will suck air through the crack. It will not leak fuel because the hose is above the tank. This was one of the problems I had. The hoses "looked" good until I removed them. The pumps are easy to test. Just remove the hoses and put a new hose at the intake of the pump into a full fuel can. Remove the hose at the carb put it in a bucket. Disconnect the the connector at the distributor and turn the engine over. You should see a steady stream of fuel. There are specs for the volume of fuel if you want to look it up. You can also put in inline electric pump at the tank as a back-up in case the machanical unit fails. I have done this in all the RV's I have owned. I have a filter in front of each pump and one at the carb to catch anything from the fuel lines or if one of the pumps failed and put shrapnel in the fuel lines.

Moved Reply:

Neil,

PSI & GPH of the fuel pumps you installed?.....Thanks!

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Danny,

Here's a site that offers a hodge-podge of possible solutions to problems somewhat similar to yours:

http://www.rverscorner.com/info/rough454.html

In my case, symptoms like yours were corrected when I R&R'd the coil and the ignition module I replaced both at the same time, so I don't know what the culprit was, but I have to think that the coil in an HEI takes a temperature beating being cooped up in the top rear of a motorhome doghouse....Good luck!

Moved Reply:

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Originally posted by Lee:
Neil,

PSI & GPH of the fuel pumps you installed?.....Thanks!

Here is a link to one.
http://cgi.ebay.com/ebaymotors/Carter-P4070-Fuel-Pump-E....l1247QQcmdZViewItem
I bought mine at NAPA but they are avaliable at a lot of places.

Moved Reply:

Let's get the stupid questions out of the way.
1. Can I install the electric back near the splitter and leave the mech in place? Would I want to?
2. Can I use that electric as a replacement for the in tank pump in my old 91 Cheby pickemup 350? I really don't want to pull the tank and put in that expensive beast if I don't have to.

Moved Reply:

quote:

Originally posted by Danny Z:
Let's get the stupid questions out of the way.
1. Can I install the electric back near the splitter and leave the mech in place? Would I want to?

It depends. If you dont have the "return" system like I do It should flow through the pump to the carb. That is why you could use it as back up or if you think you have a problem with vapor lock. I friend of mine had a REVCON that came from the factory with a back-up electric fuel pump installed. I think a mechanical fuel pump like mine with the "return" would work but I am not sure. I am far from an expert on a Chevy so someone else may be of more help.

quote:

Originally posted by Danny Z:
2. Can I use that electric as a replacement for the in tank pump in my old 91 Cheby pickemup 350? I really don't want to pull the tank and put in that expensive beast if I don't have to.

No, you would need the correct fuel pump for the fuel injection on that Chevy.

I installed a booster pump on our 84 28' unit. I have one large 70 gallon tank mounted between the frame rails directly behind the rear axle. The tank has an aluminum picup tube, that clears the bottom of the tank about 1/2". I believe that fuel moves around enough to allow a small amount of air in the inlet of the tube, and that air bubble has to be pulled to the mechanical pump and returned to the tank, or carburator....and it will starve for fuel. I mounted an electric pump (pulse type from Autozone) on the outside of the frame rail to suck fuel from the tank and push it forward to the mechaincal pump. I need to finish up the job by installing a oil pressure switch to control the pump and a bypass (primeing) switch to activate the pump to make it easier to start if I run out of fuel. I think this is the best solution for my unit due to the tank design, unless I want to keep at least 1/2 tank of fuel in there (35 gallons)

I hope this helps...