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914World.com _ The Paddock _ Fuel Pump Question
Posted by: BadToTheBown Sep 7 2020, 08:42 PM
I'm the new proud owner of Tom's old track car (914/6 2.4) and I'm getting ready to club race it (SWMS in ABQ NM) and I have a strong gas smell in my garage with it in there and trying to run it down. I know the fuel cell bladder was well inspected and got new foam last year and is using 2 older (pre-2013?) Mallory electric fuel pumps (pics below). I've read the smell can come from them and I'm looking at rebuilding them but cannot tell which model they are and asking if a member recognizes which they are?
Posted by: brant Sep 8 2020, 10:19 AM
I'm only guessing... look like holley low pressure maybe...
but the fuel smell could easily be coming from the carbs.
if the car has ran in the garage... then the 4 fuel bowls are full to the carbs... I sometimes drain the bowls. mine will evaporate completely in about 24-36 hours into the atmosphere on my -6 in the garage
Posted by: BadToTheBown Sep 8 2020, 07:03 PM
I'm only guessing... look like holley low pressure maybe...
but the fuel smell could easily be coming from the carbs.
if the car has ran in the garage... then the 4 fuel bowls are full to the carbs... I sometimes drain the bowls. mine will evaporate completely in about 24-36 hours into the atmosphere on my -6 in the garage
Thanx for the follow-up. They're Weber 40 IDA3Cs, I have a lot to lean about Webers, not to mention Porsche boxers, are the bowls hard to drain and I'd be interested in some pics of how you painted your car, I might make some changes to mine and looking for ideas...
Posted by: stownsen914 Sep 9 2020, 01:34 PM
Especially if you are running pump gas, draining the float bowls is a good idea when the car sits. Today's pump gas gums up carburetors.
This may be what Brant was saying, but another reason for gas smell on a carbed car - if you run the fuel pump for a while with the engine off, gas will overflow from the float bowls and start dumping into the engine. This isn't great for obvious reasons, two of them being gas smell and potential fire hazard.
Nice purchase, by the way. I noticed the car for sale and thought it looked like a good deal. And welcome to 914 World!
Posted by: BadToTheBown Sep 9 2020, 01:43 PM
Especially if you are running pump gas, draining the float bowls is a good idea when the car sits. Today's pump gas gums up carburetors.
This may be what Brant was saying, but another reason for gas smell on a carbed car - if you run the fuel pump for a while with the engine off, gas will overflow from the float bowls and start dumping into the engine. This isn't great for obvious reasons, two of them being gas smell and potential fire hazard.
Nice purchase, by the way. I noticed the car for sale and thought it looked like a good deal. And welcome to 914 World!
Thanx and Tom's a great guy. Wish we could hang out but he's 2 state too far away.
They are 2 low pres pumps, looks like 4 lbs on 1 pump and close to 9 lbs on 2 pumps. I'm still figuring out why I have 2 pumps. I see 4 lbs for idle (to not overcome the bowls) and I can see 8 lbs for WOT but I think I need a lot more HP to need the 2nd pump. This engine probably only makes 180 or so HP.
I don't know how to drain the bowls (is on pump gas, 93 octane), so I'm guess I'm going to learn, thanx...
Posted by: brant Sep 9 2020, 02:07 PM
I can't really tell the routing and plumbing from your pictures.
usually 2 pumps are used when there is a surge tank
I have that set up in my -6 race car
do you have a separate surge tank that one pump fills?
on most systems... one pump fills the remote tank
the other pump feeds the carbs from the remote tank
the surge tank is used to prevent fuel slosh in the big tank that would cause pick up problems in a corner
(it was created for FI systems that are more sensitive to pressure changes than the bowl of a carb. would be)
each carb has 3 throats... but only 2 bowls
a brass bolt, 10mm head... is the drain to the bowl
the bowl is between two of the throats
if it wasn't snowing.. I'd go get you a picture..
so draining the bowls: I use a butter container... small margarine or even yogurt container
it has to be small to fit up tight to the screw... pull the screw, drain the fuel into the plastic container and put the screw back in.
you don't want to over tighten these hollow brass screws... that thread into fragile castings
Posted by: BadToTheBown Sep 11 2020, 09:43 PM
I can't really tell the routing and plumbing from your pictures.
usually 2 pumps are used when there is a surge tank
I have that set up in my -6 race car
do you have a separate surge tank that one pump fills?
on most systems... one pump fills the remote tank
the other pump feeds the carbs from the remote tank
the surge tank is used to prevent fuel slosh in the big tank that would cause pick up problems in a corner
(it was created for FI systems that are more sensitive to pressure changes than the bowl of a carb. would be)
each carb has 3 throats... but only 2 bowls
a brass bolt, 10mm head... is the drain to the bowl
the bowl is between two of the throats
if it wasn't snowing.. I'd go get you a picture..
so draining the bowls: I use a butter container... small margarine or even yogurt container
it has to be small to fit up tight to the screw... pull the screw, drain the fuel into the plastic container and put the screw back in.
you don't want to over tighten these hollow brass screws... that thread into fragile castings
Saw you guys got snow. Sandia down here did too. I'm in the foothills, so just rain. I'll find it, thanx for pointing me. I'm going to map out the oil cooling and fuel systems and I'll look for a surge tank...
Posted by: 914 Ranch Sep 17 2020, 01:45 PM
I had the same problem, I installed a off switch on the ground circuit to the fuel pump. When I shut the car down I turn off fuel pump and run her out of fuel.
No more gas smell in the garage unless there's a problem.
Posted by: BadToTheBown Sep 18 2020, 12:10 AM
I had the same problem, I installed a off switch on the ground circuit to the fuel pump. When I shut the car down I turn off fuel pump and run her out of fuel.
No more gas smell in the garage unless there's a problem.
Hmmm....I'm wired to do that now, I'll try it, thanx....
Posted by: PlaysWithCars Oct 5 2020, 09:47 PM
Be patient. It will probably take longer to run the bowls dry than you think it should. You can probably hear your fuel pumps running. Rest assured that if they aren't running when you start the car, that you're just running on the fuel bowls and they will eventually run dry.
Posted by: BadToTheBown Oct 5 2020, 10:08 PM
Be patient. It will probably take longer to run the bowls dry than you think it should. You can probably hear your fuel pumps running. Rest assured that if they aren't running when you start the car, that you're just running on the fuel bowls and they will eventually run dry.
Did it, it doesn't take long to run out, still have gas smell but less, thanx...
Posted by: 914 Ranch Oct 6 2020, 08:02 AM
That completely cured mine. My tank vents my fuel in the tank dry and I don't smell anything. Before I installed the off switch I went looking for a leak every where, I found a couple of places that were wet and fixed them but when everything was dry I still smelled fuel. I kept sniffing around the tank but it was not the source. It was the carbs so I installed the switch. The fuel lineholds a miniscule amount of fuel and tightening up the connections stopped the wet spots. Now I smell gear oil like 90 weight. But it doesn't bother me. My fuel tank is made for a drag boat and is conical at the bottom. With a very large vent at the top. It seems to breathe fuel cause it's always dry.
Posted by: BadToTheBown Oct 6 2020, 07:42 PM
That completely cured mine. My tank vents my fuel in the tank dry and I don't smell anything. Before I installed the off switch I went looking for a leak every where, I found a couple of places that were wet and fixed them but when everything was dry I still smelled fuel. I kept sniffing around the tank but it was not the source. It was the carbs so I installed the switch. The fuel lineholds a miniscule amount of fuel and tightening up the connections stopped the wet spots. Now I smell gear oil like 90 weight. But it doesn't bother me. My fuel tank is made for a drag boat and is conical at the bottom. With a very large vent at the top. It seems to breathe fuel cause it's always dry.
It's better, not cured. I've also read it can be the fuel pumps (membrane in them) but cannot see any clear evidence of that. Their race Mallorys...
Posted by: Charles Freeborn Oct 22 2020, 09:29 AM
Mine runs a Holley. I'll snap a pic when I'm in the garage next.
When you have a minute could you post a pic from further back of the bracing in your front trunk? Mine has had the bulkhead wall cut out too but no reinforcement. That's a project for this winter on mine. Thx.
Posted by: BadToTheBown Oct 22 2020, 07:38 PM
Mine runs a Holley. I'll snap a pic when I'm in the garage next.
When you have a minute could you post a pic from further back of the bracing in your front trunk? Mine has had the bulkhead wall cut out too but no reinforcement. That's a project for this winter on mine. Thx.
As requested...
Attached image(s)
Posted by: Charles Freeborn Oct 23 2020, 10:36 AM
Thanks!
I'll uncover mine today and get a snap of the FP. I'm planning a fuel cell swap this winter and while that's all apart it's a good time address some stiffening issues.
-C
Posted by: Charles Freeborn Oct 23 2020, 06:25 PM
My pump and filter. Holley “Red Electric” 
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