Fuel dumping w/ Edelbrock 1406 [Archive] - Team Camaro Tech

: Fuel dumping w/ Edelbrock 1406


boboftherockies
Sep 6th, 07, 08:05 PM
My 69 w/ a more or less stock 350 has what appears to be fuel dumping. When it's been driven for a while and I shut it off and come back to start it in 30 min.....It won't idle, smells like gas and stalls. It eventually settles down after holding RPMs up for about 5 min. Engine temp never gets above 190, so heat soak doesn't seem to be it.
It has a new Edelbrock 1406 carb with the heat insulator under it on a performer EPS manifold. Plugs are new and are not fouling, timing is 12 deg advance at 750 rpm. New AC Delco stock style fuel pump. In line Russell filter.

The carb has been tuned for my altitude in Denver (about 6000 ft at my place) by jetting down 2 steps and rod changes - according to the tuning guide. I checked and double checked the floats... all is to spec. I've even tried to lower the floats a bit, cleaned out the idle ports, made sure there's no vacuum leaks but it's still doing this..

What might be causing this? :confused:What's next in working out a solution?.... pressure regulator? Trash the Eddy for a Holley? Is the still a problem with Holleys?

I know others have worked through this.... please help!
Thanks
Bob

stamatisg1977
Sep 6th, 07, 08:11 PM
mine did the same thing. just add a 1/2" spacer under it and the problem will be cured

parkbrau
Sep 6th, 07, 10:20 PM
Sounds like you have the same problem as I do. I have same set up except I have a edelbrock manifild. I drive it around, come back home park it and it smells of fuel. i lift off the air cleaner and I can see fuel pooling in the carb. Anyway, I e-mailed edelbrock. The guy with the 30 pound head says that the stock fuel pump is putting out to much pressure. So i bought the Summit pressure regulator and am now waiting for my plumbing fittings to get here. Once I get it all plumbed i'll let you know.

Newbomb
Sep 6th, 07, 11:01 PM
I had the same problem!

72Tugboat
Sep 7th, 07, 12:32 AM
I had the same problem, and found that the plugs in the bottom of my carb (Edelbrock 600) were leaking, causing the problem in my case. I put some epoxy over them, problem solved!

Good Luck!

DenRS
Sep 7th, 07, 06:27 AM
What's your fuel pressure? If your not running a stock fuel pump you most likely need a fuel pressure regulator. I have mine set at 5.5 psi and my 69 camaro runs great with the 1406. The manual says anything over 6psi is too much so i set mine at 5.5 to be on the safe side.

boboftherockies
Sep 7th, 07, 09:20 AM
What's your fuel pressure? If your not running a stock fuel pump you most likely need a fuel pressure regulator. I have mine set at 5.5 psi and my 69 camaro runs great with the 1406. The manual says anything over 6psi is too much so i set mine at 5.5 to be on the safe side.
I don't know what the fuel pressure is, but the pump is an AC Delco stock-style pump (got it from Ricks 1st gen). Doesn't seem like it should run more than 6 psi, but I just can't say for sure.

How much of a pain is it to put in a regulator? Are there pumps that do a better job of regulating psi that's a cleaner solution than an external regulator?

Bob

Brentmc
Sep 7th, 07, 09:22 AM
Do you really need a pressure regulator with a stock fuel pump?......

deerhunter
Sep 7th, 07, 09:31 AM
Yes. I have one of them and even with the stock pump I had to install the regulater. This is one of many issues that make me prefer Holley carbs.

Brentmc
Sep 7th, 07, 09:41 AM
So the stock delco pump puts out more the 5.5 and therefore needs regulated in order to properly feed the 1406?

boboftherockies
Sep 7th, 07, 09:44 AM
Yes. I have one of them and even with the stock pump I had to install the regulater. This is one of many issues that make me prefer Holley carbs.
Which Holley is a good replacement for the Eddy 1406. Street application.

boboftherockies
Sep 7th, 07, 10:54 AM
So the stock delco pump puts out more the 5.5 and therefore needs regulated in order to properly feed the 1406?
I have a theory... I'm at 6000 ft in elevation. The air pressure here is 25% less than at sea level. So... wouldn't a pump that produces 6 PSI at sea level produce 25% more pressure (from less atmospheric resistance) at 6000 ft? That would be 7.5 PSI... and enough to cause the problems I'm seeing.

What do you think?

forttusken
Sep 7th, 07, 11:22 AM
I have a theory... I'm at 6000 ft in elevation. The air pressure here is 25% less than at sea level. So... wouldn't a pump that produces 6 PSI at sea level produce 25% more pressure (from less atmospheric resistance) at 6000 ft? That would be 7.5 PSI... and enough to cause the problems I'm seeing.

What do you think?

Pressure of a liquid is hardly affected by the atmospheric air pressure at all. We are just went over this in my fluids class. The atmoshperic pressure does have a huge affect on fuel mixture but you seem to have that sorted out. I can't get my engine to start with my new Edelbrock, I guess I will try with a regulator.

deerhunter
Sep 7th, 07, 01:51 PM
Which Holley is a good replacement for the Eddy 1406. Street application.

I used the 670 Street Avenger and right out of the box it worked fine.

77wolf10.85
Sep 7th, 07, 02:13 PM
PSIG is gauge pressure.

PSIA is Absolute pressure, or gauge + atmospheric

6PSIG at sea level is about 20.7 PSIA
6 PSIG at higher elevations is less. I work at 3000' a lot and we use 13 for atmospheric. So 19 PSIA, and in Denver it would be about a pound less.

But The 6 PSI is relative to the geometric advantage of the particular float and needle/seat. Atmospheric doesn't come into play here.

Bob didn't you have another thread with the same problem? Or am I confused between posts again:D

My 2 cents

edit: by the way gauges have to be calibrated for altitude. Cheapo gauges don't have that capability.

boboftherockies
Sep 7th, 07, 02:55 PM
PSIG is gauge pressure.

PSIA is Absolute pressure, or gauge + atmospheric

6PSIG at sea level is about 20.7 PSIA
6 PSIG at higher elevations is less. I work at 3000' a lot and we use 13 for atmospheric. So 19 PSIA, and in Denver it would be about a pound less.

But The 6 PSI is relative to the geometric advantage of the particular float and needle/seat. Atmospheric doesn't come into play here.

Bob didn't you have another thread with the same problem? Or am I confused between posts again:D

My 2 cents

edit: by the way gauges have to be calibrated for altitude. Cheapo gauges don't have that capability.
Tim;

Thanks! Yes, the other thread started with vacuum leaks and other idle issues. Got those solved, but this fuel dumping problems remains.

Bob

JimM
Sep 7th, 07, 04:13 PM
I realy don't think this is fuel pressure related.

Have you opened the carb and checked the needle and seats, and the float level, recently? She mighta swallowed a wad of crap or smomething.

Badbird
Sep 7th, 07, 04:49 PM
Does the engine appear to be loading up and running on the rich side?.....Are you running a lopey camshaft?.....How many inches of vacuum is the engine pulling?......It sort of seems to me that the metering rods are not staying down at idle......Did you use the same color metering rod springs when you rejetted?

boboftherockies
Sep 7th, 07, 05:10 PM
I realy don't think this is fuel pressure related.

Have you opened the carb and checked the needle and seats, and the float level, recently? She mighta swallowed a wad of crap or smomething.
Jim;
Yes, opened it yesterday to check the floats (again) and don't see any junk in the bowls. I also blew out the idle needle seats last week to no avail... It always does the same thing.... it acts like it's flooded after driving, then shutdown and in 15 - 30 min restart.... won't idle and smells flooded. If I wait a few hours before restart, it's fine. I have the heat insulator installed....no help. It never gets above 190 deg.

Bob

boboftherockies
Sep 7th, 07, 05:15 PM
Does the engine appear to be loading up and running on the rich side?.....Are you running a lopey camshaft?.....How many inches of vacuum is the engine pulling?......It sort of seems to me that the metering rods are not staying down at idle......Did you use the same color metering rod springs when you rejetted?
Ron;
It's actually running 2-3 steps lean (jets + rods) on the Eddy tuning chart... I'm at 6000 ft in the Denver area. Very stock-type cam. Don't know the in-vacuum, but it seems ok. Haven't changed springs on the carb yet, so they are stock.

boboftherockies
Sep 22nd, 07, 01:20 PM
Sounds like you have the same problem as I do. I have same set up except I have a edelbrock manifild. I drive it around, come back home park it and it smells of fuel. i lift off the air cleaner and I can see fuel pooling in the carb. Anyway, I e-mailed edelbrock. The guy with the 30 pound head says that the stock fuel pump is putting out to much pressure. So i bought the Summit pressure regulator and am now waiting for my plumbing fittings to get here. Once I get it all plumbed i'll let you know.
Just finished adding a Holley pressure regulator...and, viola! All starting and idling problems are solved. Apparently, the Eddy carb is very sensitive to fuel pressure. I also added a Summit fluid filled gauge to determine what the pressure is at the carb. It's not working right, though, as the pressure starts out at 5 PSI (just about right for the Eddy) and drops to 0 in 15 minutes or so. Engine does not change while this happens, so it must be a gauge issue. I mounted it on the outlet side of the regulator in a vertical position. Are there any problems with that way of setting up the gauge?

kgmunro
Sep 23rd, 07, 07:35 PM
my kitty likes sitting and looking out the window.