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TurboVan
04-03-2002, 10:56 PM
A while back a bypass filter was discussed to relieve the fuel pressure after shutting off the engine.
I picked up a couple of them, each has a 1/4" return line with an .060" orifice.
For 3/8 hose: Carquest #86041
For 5/16 hose: #86040
TV

65dream
04-04-2002, 11:06 AM
tv can you explain what this is for caus e my van smells lkike gas . thanks from frank

TurboVan
04-04-2002, 10:15 PM
It lets out the fuel pressure to the carb immediately after the engine shuts off, so the carb doesn't "overflow" during heat soak.
It also reduces the fuel pressure during running a little bit, but not enough to have any effect. I wish I had some way to diagram the plumbing.
TV

Tnicean
04-05-2002, 07:26 AM
Hi 65 Dream, sounds like your float in the carb is not shutting the gas off completely. When you shut the engine off, the gas continues to seep into the intake and fumes come out the top of the carb. The 2 barrels are easy to rebuild. If you have a four barrel, you may want to get someone to look at it.

painterchris
04-05-2002, 09:20 PM
My van often smells like gas after I shut it off and it seems to be from the pressure buildup already discussed. When the van is turned off, the line pressure is so high that I actually get a tiny jet of gas squirting out of the mixture screw onto the manifold. The hot manifold immediately evaporates it, causing the smell.

TV, if you ever draw up a plumbing diagram, I could use one.

Later,
Andy.

leadfoot
04-05-2002, 09:40 PM
be careful that HOT manifold
"evaporates" that fuel but it's not the liquid that burns it's the fumes -
i knew someone who had a leaking injector on a honda and they thought the same thing
"it's not that bad and the little that leaks out "evaporates""-WELL POOOOOOOOF!
he went out one morning started the car to warm up and go to work-went inside the house -came out 5 minutes later-honda BBQ
buy a fire extinguisher and fix it
hate to see anything like that happen
be safe VAN~ON

[This message has been edited by leadfoot (edited April 05, 2002).]

Tnicean
04-06-2002, 07:34 AM
My fuel pump was leaking a bit on my '69...drip...drip...drip kind of thing. I noticed after I got to work one afternoon at the truckstop where I worked then. I got off at 12AM and started home. Figured I would check it out the next day. Afterall, it wasn't leaking much. About halfway home, I had to stop at a stop sign and I noticed the reflection of flames on the dirt bank next to me. I jumped out and looked underneath the van and the motor was on fire at the fuel pump. I figured that while I was moving, the wind kept it from flaming up, but when I stopped, the exhaust ignited the gas or fumes. A car happened by and they went and called the fire department. (days before cell phones too). They arrived after about 5 - 10 minutes. The fire overheated the radiator, blew the top off and blew the motor cover open. I got in and closed that back down. Damage was all wiring and hoses burned off. Filler neck was blown off the radiator. Side of driver's seat burned. I was lucky I didn't loose the van. Don't take chances. Get it fixed.

[This message has been edited by Tnicean (edited April 06, 2002).]

TurboVan
04-08-2002, 07:51 PM
That's why I always carry a fire ext in the van. (my old van club required it, had one ever since)
TV

TurboVan
04-08-2002, 08:16 PM
Mine does it, and I know the needle, seat, and float level are OK.
I think the fuel expands and the pressure rises because of heat, and overcomes the float pressure, gas spills over onto the throttle plates, into the engine and out the throttle shaft onto the manifold. To fix it , install one of the filters previously mentioned, run the 1/4" return hose back down to the fuel pump and tee it in at the pump inlet hose.
TV

vannman67
04-09-2002, 09:23 AM
TV, does it matter where you install this pressure relief filter in the line? I assume it must be installed between the fuel pump and the carb, but is there a BEST place to put it?

------------------
Vannman67
aka Bryan Corbitt
Vancouver,Wa
1967 Chevy Sportvan 108"

painterchris
04-09-2002, 07:24 PM
TV, I was about to ask the same question. My fuel line is steel from the fuel pump to the carb. Where is the best place to cut it so that I won't have rubber hose against the engine anywhere (which is a fire hazard)?

Later,
Andy.

TurboVan
04-12-2002, 12:28 AM
Anywhere, as long as it's in a straight section, and not too near the ends.
Use a small tubing cutter (not a hacksaw!), and be sure to double-clamp the hoses on the tubing (but not on the filter).
Another way is to get barbed fittings for the fuel pump and carb and use all hose.
TV

JD
04-12-2002, 11:42 PM
Hey Turbo , where does the 1/4 inch bypass hose go? Does it just vent underneath? I know the newer cars have them but they return the fuel to the tank. I had kind of similar problem with some of my cars in the past (hot climate) and I installed aluminum insulator plates between the carb and the manifold and seemed to fix it.. I just got a rebuild on mine and the damn thing is puddling on the manifold again (from air/fuel mix screws).......Thanks.....JD

TurboVan
04-13-2002, 01:59 AM
The bypass hose tees in at the hose coming from the tank to the fuel pump, anywhere in this hose, it doesn't matter. That's how it returns to the tank.
TV

gregw98
04-13-2002, 07:03 PM
Bought and hooked up my bypass filter and also bought a fire extinguisher today. T.V., your advice makes good sense. Thanks for bringing this to our attention.
Greg

TurboVan
05-01-2002, 12:41 AM
I just hooked up the bypass on TacoVan today, and to make it easier, I used all hose, and two of those filters: one just before the fuel pump (replacing the original filter and providing a convenient "tee" for the 1/4" return hose), and another, turned around backwards, between the fuel pump and carb (to let out the residual pressure).
I did have a problem though. It wouldn't start! Since the system was dry, air just went around and around in the hoses, and the system wouldn't prime. So I temporarily pinched off the return hose with vise grips, and it started right up!
I suppose I'll have to do it again if it ever runs out of gas...
Anyway, well worth the trouble to eliminate the flooding, hard starting, and gas smell!
TV

vannman67
01-26-2003, 01:24 PM
So you install the new filter with the 1/4" outlet in reverse? So the 1/4" hose is already heading down?

------------------
Vannman67
aka Bryan Corbitt
Vancouver,Wa
1967 Chevy Sportvan 108"
www.home.attbi.com/~bcorbitt68

gregw98
01-26-2003, 03:10 PM
2 filters, good thinking TV. Makes it a quick and easy setup. I forgot to mention about the dry start.
greg

vannman67
01-26-2003, 04:24 PM
Well, I got it all hooked up. Had enough fuel line to get up away from the block and manifold. That should make a difference in itself. I aimed the 1/4" outlet down toward the ground, opposite the flow direction. Started right up. When I shut it down I could hear the extra fuel draining back into the line before the fuel pump. Great idea. Hope it takes care of that damn smell.

------------------
Vannman67
aka Bryan Corbitt
Vancouver,Wa
1967 Chevy Sportvan 108"
www.home.attbi.com/~bcorbitt68

tanglefoot
01-27-2003, 04:47 PM
OK,
I read what everyone had to say about the cure for the gas smell problem.
so here was my approach.
www.sonic.net/tfoot/smell.htm (http://www.sonic.net/tfoot/smell.htm)

Thanks,
Foot

jimrhoads
05-05-2003, 12:44 PM
I had the gas smell/gas running out of the carb/flooding problem too but I replaced the chrome gas cap my vans previous owner put on with an original style replacement cap and all the problems seem to be gone. I smell gas once in a while, but since I'm sitting next to the motor I would expect that, but the gas running out of the carb and flooding has stopped. My mechanic thinks the problem was due to pressure buildup caused by improper cap venting.

TurboVan
05-06-2003, 11:48 PM
That's a good idea.
I guess if when you take off the gas cap and you get air escaping, you better change the cap, otherwise the bypass will not help.

TV

Tnicean
05-13-2003, 08:52 PM
When you loosen the cap and you can hear air, it is air going into the tank if you don't have a vented cap. The fuel pump is sucking a vacuum on the tank. I replaced my original cap with a shiny new (unvented) cap and the fuel pumps (I replaced several) were sucking a vacuum to the extent that the tank flexed so much that it cracked. I have had it repaired several times over the years. I hope to get a tank from BZ and maybe it will be the end of that problem.
Tnicean.

TurboVan
05-13-2003, 10:19 PM
The cap should be able to breathe in or out, to avoid problems.

TV

leadfoot
05-19-2003, 08:22 PM
now here's a stumper-
i have one of them new chrome caps
breather on top only lets air in
-i also have one of them tin twist cheapy caps.. and that one only vents out
....still smell gas after shutdown
using both of em
maybe if i drill a hole straight through the vent in the cap....mmmmm
where's my cordless drill LOL- yes i'll take the cap off the van first haha
-the vent line return line is probly the best fix i've heard yet
VAN~On

shorty
01-04-2006, 07:49 PM
I'm using a chrome cap I bought from lmc truck. In the summer The van smells like gas BAD. After shutdow the manifold shows signs of seepage also. When I remove the gas tank cap on a hot day the gas cap is hard to turn, and when i can finally get it off there is a swooooosh of air coming out of the tank. I am going to do the return line swap this weekend. If the chrome type cap is no good what should i use? Or is there a way to make the chrome cap went properly. Shorty

gregw98
01-04-2006, 11:12 PM
All you need is a vented cap. I ran a drill bit into the little plastic tip inside of the cap.
greg

shorty
03-13-2006, 07:50 PM
Did the conversion this weekend. Turned out pretty slick thanx for the tip guys. I drove all the way to car quest and they didn't have one, so then i went to napa and had them cross the car quest #, then they dint have one so I went to VIP and had them cross the napa and the car quest and they didn't have one. I ended up picking one up off the shelf and replacing all of my fuel lines to make it work. The double filter is the way to go seems a lot safer to me and easier. I am going to replace the plastic "T" with another filter this weekend. Shorty

chevy van 5150
03-13-2006, 10:46 PM
I have a locking chrome gas cap I got from Brothers I think it was for a 68 P/U it is vented and looks like original. I have a 4 barrel carb. and an open element air cleaner but have never smelled gas? wondering if I should do the mod? what do you think TV?

TurboVan
03-14-2006, 09:36 PM
Probably not.
Keep it simple.
If it ain't broke, don't fix it!

TV