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quadrajet carb
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Picture of BarthBluesmobile
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I'm concerned about a weak spark; perhaps the HEI module is dying. If you have the distributor checked and the weights in it, maybe just have a new one put in.

good luck!
Matt


1987 Barth 27' P32 Chassis
Former State Police Command Post
Chevrolet 454
Gibson Exhaust
 
Posts: 321 | Location: Massachusetts | Member Since: 07-28-2006Reply With QuoteReport This Post
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Formally known as "Humbojb"
Picture of Jim and Tere
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Well, one thing for sure, it's either electrical or fuel Frowner. Does yours have two gas tanks? Does it happen on either one? If so, that probably rules out fuel tank filters. What kind of fuel pump did he put in? Did it have a return port, supposed to help with vapor lock. It would attach to a 5/16" line going all the way back to the tank. The fact that it ran ok for a whole day after he did some work on it seems to be significant. Do the easiest things first, as in fuel filters, fuel lines, return lines, back pressure in exhaust system.


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3363 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
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Picture of Lee
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I cured some similar symptoms with the R&R of the HEI ignition module. (If you try this, make sure you use the grease packet - acts as a heat sink).
 
Posts: 1408 | Location: Frederick, Maryland | Member Since: 09-12-2003Reply With QuoteReport This Post
Picture of Brady and Hilary
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You're right Bill. I'm extremely frustrated, and knowing that it's something simple but I can't figure it out makes me more so.

I just talked to the mechanic in Ohio that replaced the fuel pump, which does have a return line Jim. He said that he checked the distributor weights and they were free Matt. He also said that you can't really check the voltage to the coil but that they usually have a hole burnt in the top if they are bad. He thinks it's vapor lock too and told me to put wooden clothes pins on the fuel line anywhere I could. They supposedly absorb the heat.

I'm definitely going to try driving with the gas cap off.

Could the PCV valve have anything to do with this? I noticed yesterday morning before we took off that the tube wasn't connected to the air cleaner so I reattched it. That means that it would have been disconnected on Friday when we drove from OH to KY without incident. Yesterday it was connected and we had trouble. Coincidence?


1986 Regal 25ft.
454 Chevy
 
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Glassnose Aficionado
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Picture of Danny Z
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I don't know how I never came across this thread before but I'll put in my 2 cents worth now that I've properly purused it. I have no doubt that the problem is vapor lock, and I have no doubt that everyone else will say I'm FOS. The single biggest problem with the P series 454 was vapor lock. This from a friend who worked for a bunch of Indiana coach builders and has creds that I couldn't touch. The splitter valve sitting within inches of the exhaust sets up a perfect environment for gas to boil, then when you need it, the vapor just laughs at you. So go ahead and tell me I'm wrong, but I'll be at Nicks for the Memorial day GTG, and won't worry about a hundred little things, just the one obvious one.


79 Barth Classic
 
Posts: 3592 | Location: Venice Fl. | Member Since: 07-12-2004Reply With QuoteReport This Post
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quote:
Originally posted by Danny Z:
I have no doubt that everyone else will say I'm FOS.


I won't. It could be vapor lock.


.

84 30T PeeThirty-Something, 502 powered
 
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quote:
Originally posted by Brady and Hilary:
He said that you can't really check the voltage to the coil but that they usually have a hole burnt in the top if they are bad.


Not always. I had a weak coil that pooped out uphill. It gave itself away by causing a nice bang in the exhaust accompanied by enough flame to melt the decal off the door of a Highway Patrol car. The spark failing for a while allowed the exhaust to fill with unburned fuel. When the spark did come, it was quite dramatic at night.

quote:


He thinks it's vapor lock too and told me to put wooden clothes pins on the fuel line anywhere I could. They supposedly absorb the heat.



I have my doubts on vapor lock, only because it is April. Another reason to doubt VL is that you have a properly working (I hope he checked it) vapor return system and the half inch fuel lines. The only shortcoming of the vapor return line is that it does not address any vapor lock generated between it and the carb. BTW, does the carb have a base insulator? Usually lack of this shows up by the fuel in the float bowl vaporizing after stopping. But, I am not there, so I'm not gonna rule out VL.

Another old trick, which works better for me, is to wrap any fuel line near any heat with several layers of crinkled aluminum foil. The foil acts as an insulator to keep the heat away. The theory is that the fuel races through the line before the heat can get to it. Thermo Tec sells tubing for this purpose, as well. I use it on my plug boots.

However, the best treatment of the symptom is to install an electric fuel pump as close to the fuel tank as possible. There was a service bulletin that recommended installing 1/2 inch fuel line and an electric pump. In fact, the electric pump at the back is all I have on my rear tank 30+-footer.


.

84 30T PeeThirty-Something, 502 powered
 
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Picture of Bill N.Y.
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quote:
Originally posted by Danny Z:
...I have no doubt that everyone else will say I'm FOS. The single biggest problem with the P series 454 was vapor lock.
I would never tell you that you're FOS because...
quote:
Originally posted by Bill N.Y.:
...unless I'm diagnosing it myself I can only guess at a few different things.
It very well may be vapor lock.
quote:
Originally posted by Bill N.Y.:
I could go on for awhile asking you to check this that and the other thing. I wish I could just tell you what it is...
...but I can't.


˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

Regis Widebody1990 Barth Regis Widebody
8908 0128 40RDS-C1
L-10 Cummins
Allison MT647 Transmission
Spartan Chassis
Regal Conversion1991 Medical Lab Conversion
9102 3709 33S-12
Ford 460 MPFI
C6 Transmission
Oshkosh Chassis



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Posts: 7298 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
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I would think it was vaporlock if this happened in traffic but on the open road doubtful. That 454 is sucking a lot of fuel at highway speed and that alone is keeping VL at bay to a pretty good degree.
I stand in the line that says electricity. Especially if you can get to the road fully warmed up before having the problem.


Money can't buy poverty
 
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quote:
Originally posted by ccctimtation:
I would think it was vaporlock if this happened in traffic but on the open road doubtful. That 454 is sucking a lot of fuel at highway speed and that alone is keeping VL at bay to a pretty good degree.


Lots of vapor lock out here on hot climbs at 60 mph.


.

84 30T PeeThirty-Something, 502 powered
 
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Okay, still think electricity but an electric fuel pump is s pretty good addition for under a $100, diy.


Money can't buy poverty
 
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Yes, a $100 dollar investment might sound like a good idea to you, me, Bill H and several others...

But, there are some out there that like to see instant gratification when they have a problem. Especially one who travels with a wife, kids, or friends and who also have to deal with their concerns.

If each time you go out it becomes a mechanical adventure... Well, for me it would just be another day because I do this for a living... But, for the vast majority it would cause several real, and not so real, medical terms to come into play. Psychiatrist, General Practitioners, Nurses and Heart Specialists could make a mint helping out stranded RV'ers the world over.

Let's get back to reality and keep this thread in the real world for a few seconds... We each offered great advice, and we know that the day the Barth left the factory it didn't suffer from this problem. This developed over time and maybe even neglect.

Neglect is a strong word and it isn't used to describe a willful attempt to starve something of needed attention. It is meant to describe shortcomings of the people who maintain said items.

I've neglected things and I've had to pay the price... thankfully my neglect translates into stuff like calcium deposits on my water well pump hi/low psi switches, stubbing my toe in the dark because of a long burnt out light (Ok, that was just laziness) and tree branch maintenance before a snow storm. Big Grin

The saying, "You don't know enough to know, that you don't know... you know?" comes into play. If you agree with the sentence then you have hope for learning what it is.

We need to take it systematically and check off items on a long list. Older things could have several issues that could come into play that needs addressing. Here is an example.

Your 454 is suffering from a loss of power and you are the 4th owner...

Your temp controlled vacuum switch is stuck and the last mechanic adjusted the distributor advance without noticing this. The new owner has replaced that rusty thing around the gasoline door with a nice new plastic locking cap that isn't vented. The dirt worms have built a plug into the end of the rubber vent tube and the power tap that was installed on the ignition switch is drawing too many amps.

The new mechanic has just found a weak fuel pump that could be caused by... plugged vent tube, wrong fuel cap, collapsing fuel line under a load or a bad pump. Diagnosis is to replace the pump because his test has determined weak fuel psi... Maybe the right play, maybe not.

Tank is 1/2+ full and now has some breathing room to allow you to go a little farther without replaying this scenario out.

Maybe what we have here is that key tap is now allowing 7.2 volts to go to the coil when it's been on for awhile... Or that key tap has turned a 6 volt electrical sensor into a 3.8 volt sensor and now something is out of range.

Testing of all systems and realizing what can happen is the first steps... telling him to loosen up a fuel tank cap wasn't done as a joke, but was an attempt to isolate out a plugged vent tube or a bad fuel cap for free. If this takes care of his problem he has scored big, if not he can tell the next mechanic what has been done to this point that also includes this.

My Nova suffered from a stalling condition when making a hard right turn. Being 16, I had to finally figure out that the last 4 mechanics who soaked me for some cash that I didn't have should have found that bad transmission mount. Each time I went around a corner the transmission slid over and shifted it into reverse because the linkage bound up and pushed it back. Once straight it would start up and run normally again.

I hope that the next mechanic is allowed the needed time and diagnostic opportunity to check out all things. I'm relatively sure after he put in the pump he took it for a test drive and even told the owner to come back if it acted up again. But, being 100+ miles away... which incidentally sounds like he went farther than before, is keeping that one from happening too.

If it is acting like it did before and the new pump made it run normally for a much longer time then maybe it is fuel related. Maybe not...

We had one member who spent big money and many hours trying to fix his loss of power. He was then quoted several thousand dollars for a new fuel injection pump and injectors. After talking to me he spent under 200 dollars and has increased his power, lowered his fuel cost and is much happier with his coach. And all he did was replace a shutdown solenoid... err' an electromagnetic plunger. Wink

To all... Don't get discouraged because of problems... Don't go out and buy a 100k plastic pig... Don't work yourself into a tizzy. - Do have the time, patience and understanding to realize that not all of your problems can be fixed in a 1/2 hour sitcom. We'll just call this act, "To Be Continued..." Wink


˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

Regis Widebody1990 Barth Regis Widebody
8908 0128 40RDS-C1
L-10 Cummins
Allison MT647 Transmission
Spartan Chassis
Regal Conversion1991 Medical Lab Conversion
9102 3709 33S-12
Ford 460 MPFI
C6 Transmission
Oshkosh Chassis



Quick Link: Members Only Link To Send Me A Private Message
 
Posts: 7298 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
Glassnose Aficionado
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Picture of Danny Z
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I'd never recommend an electronic fuel pump as a do it yourself job, unless yourself really knows what he's doing. Years back I had a friend who bought a van from a used car dealer. Custom paint and interior, all set for his wheel chair lift and hand controls to be installed. The next morning he climbed in and started it up, then moved to the back in his wheel chair to wait for his buddy to drive him to get the goodies installed. The engine quit, but he just left it not running for a minute or so till his buddy got in the drivers seat and hit the key. They all got out but I got there in time to see the flatbed haul away the burned up frame and melted wheels. Someone had installed an electric fuel pump that was wired to the ignition switch, and when the engine quit the pump just kept on pumping and when the sparks from the starting ignited the gas it blew the doghouse clean off.
Of course it was installed wrong, but it could happen to anyone who wings it without knowing all the facts.
Back to the thread, does this cutting out occur after lifting on the throttle, such as going downhill or stopping at a light, then taking off under throttle for maybe 10 or 20 seconds before the cutting out starts? Only when hot? After many miles of serious cruising?


79 Barth Classic
 
Posts: 3592 | Location: Venice Fl. | Member Since: 07-12-2004Reply With QuoteReport This Post
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quote:
Originally posted by Danny Z:
Someone had installed an electric fuel pump that was wired to the ignition switch, and when the engine quit the pump just kept on pumping


Barth built mine like that. That is how Chevy says to wire it.


.

84 30T PeeThirty-Something, 502 powered
 
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Picture of ccctimtation
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quote:
Originally posted by bill h:
quote:
Originally posted by Danny Z:
Someone had installed an electric fuel pump that was wired to the ignition switch, and when the engine quit the pump just kept on pumping


Barth built mine like that.

I installed mine with a momentary switch for starting. During run it is held in with the oil pressure switch.


Money can't buy poverty
 
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