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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Thu Jul 29, 2010 4:05 pm Post subject: Fuel system issues |
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Ok so I'm still having issues with my fuel vaporizing out of my tank after the car is warmed up, then parked. My fuel lines are kinda funky though so that may be the problem . I wanted to run it by you guys before I start throwing money at it. Right now I have a stock fuel pump from Napa, with no return line output that I could see. I had the return line plugged (probably a no-no), and one day I unplugged it, and it had a massive amount of pressure in it (car was off). My charcoal canister is also unhooked and plugged. Once the car is warmed up, then parked, the gas smell from under the hood is overpowering. After sitting for about 10-15 minutes the car is hard to start, and it cranks for 15 seconds before even trying to fire. When cold, it starts without making a full revolution, easier than easy. Any suggestions? |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Thu Jul 29, 2010 4:55 pm Post subject: |
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You have to vent the tank somehow. Best way is to put a vented gas cap on the car, or put a spare fuel filter in the vent line (under the hood) then dump it down into the fender Ian-style.  |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Thu Jul 29, 2010 5:52 pm Post subject: |
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| I thought I did have a vented cap but I guess not if it had pressure, huh. Lol oops. So I should vent the return line? That won't cause the fuel to evaporate out of that line? |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Thu Jul 29, 2010 5:54 pm Post subject: |
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Do not vent the return line, only the vent line. That verbiage ain't just for show. . Flip your cap over. It will be obvious if it is vented or not.
Fuel will evaporate out of any vent. That's why they call it the EVAP system. It's the nature of using a liquid fuel. |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Thu Jul 29, 2010 6:45 pm Post subject: |
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Ok so the vent line can be found where...? Lol sorry I don't mess with stock systems much . I'll just plug the return line back up for now. I get paid tomorrow so I'm going to be redoing the fueling system with a good pump, filter, pressure regulator, and pressure gauge. Any suggestions on brand, etc.?
I'm just kinda paranoid about the evaporation thing since right now I lose at LEAST 3 gallons every time I park the damned thing. But thats better than the 4+ gallons that used to disappear. |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Thu Jul 29, 2010 7:20 pm Post subject: |
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| townaj wrote: | | My charcoal canister is also unhooked and plugged. |
That was your tank vent. Pull the bolt back out of it.
I bought a Summit brand fuel pressure regulator. Rebadged Holley unit. Was very pleased with that. . Also running their brand of fuel pressure gauge. Do not buy a liquid filled gauge, they read low when hot.
I've used RobbMc filters before:
http://www.robbmcperformance.com/products/filters.html
Massive overkill, but I got sick of having to stop and blow the Mr. Gasket ones out all the time. |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Thu Jul 29, 2010 7:32 pm Post subject: |
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Lol ok cool thanks!
Ok well I was going to get a Holley regulator, but I'll go with the Summit brand since I know its good. Can you point me in the direction of a gauge? I can't decide what I need. I'm hooking it up to a carb system, so theres not a 1/8 NPT fitting to attach to. I was looking at this pump: http://www.summitracing.com/parts/HLY-12-327-13/ |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Thu Jul 29, 2010 11:46 pm Post subject: |
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If you need both ports off of the regulator, then run a T-fitting for the gauge. If you only need one port for fuel then put an adapter in the other one and run the gauge like so...
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Fri Jul 30, 2010 3:30 pm Post subject: |
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Of course lol. Thanks for the help! I'll put in an order to Summit tomorrow. This puts off painting it though . But the things gas mileage is already so horrible I don't need it using fuel while its not running too. Also after I turn off the car I can see something that looks like steam coming out of the carb if the air cleaner is off. I heard the fuel is boiling in the bowl...is this true?
Ps: thats a good looking motor. Even if it does look to be a Furd.... |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Fri Jul 30, 2010 5:29 pm Post subject: |
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Fuel is getting too hot. Needs a carb spacer, or something. Does the engine run hot?
When I had that low-rise intake on the Monterey I ran a 1/2" phenolic spacer under the Holley. When I went to the mid-rise intake I couldn't fit it under the hood with the choke horn on the carb, so I ditched it. Now the fuel boils after hard runs follow by sitting (freeway offramp for example). Tried double-stacking gaskets to no avail. Need to find a 1/4" insulating spacer. Need to get an electric fan on that car too. Clutch fan doesn't kick in till the car gets way hot, but direct-drive fan sucks on the freeway. |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Fri Jul 30, 2010 7:11 pm Post subject: |
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I wouldn't call it hot, the gauge usually reads 160*. Sometimes after hard acceleration, traffic, etc. it heats up about 20* over normal. I'll order a spacer too tomorrow then. I have a low rise intake right now, but the air cleaner only had about a centimeter of clearance from the hood. I made a 2 inch cowl hood though so it should be good now.
I gotta go to some yards and see if I can find an electric fan, or dual fans, and a nose.
Edit: The engine runs cool, but the underhood temps seem really hot. The headers really pump out the heat, so maybe that contributes to the fuel boiling? |
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chevymad Master B
Joined: 11 Jan 2004 Posts: 5476
1987 Pontiac Formula
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Posted: Fri Jul 30, 2010 7:47 pm Post subject: |
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| What kind of carb are you running? Holleys usually stay pretty cool, AFB/edelbrocks boil the fuel every time. Part of the problem is our awesome 10% alky fuel. Alky boils real easy. |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Fri Jul 30, 2010 8:05 pm Post subject: |
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| Its a Holley 650 spreadbore with vacuum secondaries. It gets pretty effing hot. But hopefully I'll be getting a 750 double pumper though. |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Fri Jul 30, 2010 8:09 pm Post subject: |
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| Need to swap intakes, then. Might consider an Air Gap. Never ran one, but heard good things, and definitely should help in the fuel boiling department. |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Sat Jul 31, 2010 8:26 am Post subject: |
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| Yeah once I'm done screwing with the paint my next step is gonna be an Air Gap intake, the carb, and a Posi. But I don't know what order I should do them in. That peg leg rear is driving me INSANE!!!! |
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rjmcgee The Hammer

Joined: 08 Jan 2004 Posts: 2328
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Posted: Sat Jul 31, 2010 11:44 am Post subject: |
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| aaron_sK wrote: | | Need to swap intakes, then. Might consider an Air Gap. Never ran one, but heard good things, and definitely should help in the fuel boiling department. |
My airgap gets pretty f'ning hot. I just installed a heat spacer a couple weeks ago and that seemed to help. I made 13 passes at the track on a hot day and it started pretty good everytime. |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Sat Jul 31, 2010 2:54 pm Post subject: |
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| townaj wrote: | | But I don't know what order I should do them in. That peg leg rear is driving me INSANE!!!! |
I've put many miles on vehicles with open differentials. Hell, my truck has two of them right now. Get the carb and fueling situation figured out first IMHO.
| rjmcgee wrote: | | I just installed a heat spacer a couple weeks ago and that seemed to help. |
Pulling the one off of the Monterey was stupid. As soon as I did it I started having crappy idle and long restart times when hot. When the 4160 comes off for the secondary jet conversion, I think one of these puppies is going back under it...
http://www.summitracing.com/parts/CTR-85-154/
That's the curse of a big engine under a low hood.  |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Sun Aug 01, 2010 6:53 am Post subject: |
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Yeah I'm definitely painting and getting the fueling done first. I just want a posi so maybe I'll have a little more traction. In the rain I can't take off without spinning. No matter how lightly I feather the throttle. I need better gears too, so I might just get a junkyard rear end.
I've heard good things about the air gaps, but I don't know how much that will help, the air under the hood gets crazy hot. Probably from the headers, but I don't want to wrap them, and can't afford to coat them. So I'm not sure what to do . |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Sun Aug 01, 2010 9:46 am Post subject: |
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| How's your timing curve? To retarded can cause a lot of extra heat. |
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townaj Member
Joined: 04 Dec 2008 Posts: 326 Location: San Antone, TX
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Posted: Mon Aug 02, 2010 6:43 pm Post subject: |
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| Thats a good question. My cheap summit light broke so I have no way to check it. I took it to get tuned and the guys said it was way too advanced and was detonating. Though I didn't hear anything. It was a performance shop too. Maybe I'll pick up a decent light and see what it says... |
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