Transam.82

My set up:
A 388 with an Edelbrock 750cfm and a electronic fuel pump.

My problem:
I can start the car and it will idle and even take a load, but after a minute or two it dies. It also dies if I open my secondary. I've changed my plugs and my cables are all good. I belive it's the fuel pump, is there anyway to test that? If not what's the best way to access the fuel pump?

RedLeader289

iTrader: (2)

Does it start back up imediately after dying?

do you have a pressure gauge on your fuel line? If not you should install one before the carb, a quick look at that will tell you if your pump is working properly, should maintain about 6-6.5 psi.

Did you tune the carb after installation or did you just slap it on and go?

I'm leaning towards it being your carburetor.

Transam.82

No it does not, I have to depress the gas several times and hold the key turned for a bit.

Also I do not have a pressure gauge, I will have to looknow at getting one.

The carburetor was tuned and the car was running for a while before I acquired this problem. I drove about 50 miles or so with no problem.

RedLeader289

iTrader: (2)

Ok, well once you get the pressure gauge you have your answer for sure. If it doesn't maintain pressure at idle and under load then your pump is on it's way out.

Transam.82

Okay, is there an easy way to access the fuel tank or does it need to be dropped?

RedLeader289

iTrader: (2)

If you have to pull the pump then the tank has to be dropped. Some people have been able to jack the car up high enough to wiggle it out but ususally you have to drop the axle to have enough space.

Transam.82

Okay, thanks. If the carburetor it can just be rebuilt or complete replacement?

Sorry for all the questions, still trying to learn all the systems.

RedLeader289

iTrader: (2)

No worries, asking questions is the best way to learn!

If it was the carb you could look at having it rebuilt if needed. Rebuild kits are fairly cheap too.

midias

Rebuild kit is about $25 and they are super easy to rebuild.

I have used a dozen of these with no issues.

http://www.ebay.com/itm/EDELBROCK-CARBURETOR-REBUILD-KIT-1477-1400-140-4-1405-1406-1407-1411-1409-/400874980047?hash=item5d5602c2cf&vxp=mtr

Transam.82

I can't identify my carb, it says Edelbrock Weber 8867...

Transam.82

Rephrase; I have not seend a rebuild kit or any information on my model of carburetor. Will the above mentioned kit also rebuild mine?

midias

Plugging "Edelbrock 8867" into Google it looks like an old part number for a 140X series carb. The rebuild kit should work but I would probably email the seller and ask him first.

Transam.82

I did that last night and only pulled up 600cfm carbs and I know this is a 750, so I wasn't sure. I just plugged it in again and found it was a 1407 and at 750cfm, I must have missed it. Thanks!

Night rider327

iTrader: (13)

What's the number on the base plate?
On front left hand side right under the mounting bolt hole.

Transam.82

1407 3336

I didn't even realize there were numbers there.

Night rider327

iTrader: (13)

lol, yep most people don't. That's your model # 1407 which is a man. choke 750 cfm

The webber/carter afb/edelbrock carbs are one of the easiest carbs to rebuild. Very simple to do. In fact depending on it's age you might not even need a 'rebuild' kit.

If you are careful removing the air horn (top) and the boosters, go slow, wiggle part, etc you can get them off/out with out tearing the gaskets and I have found you normal can pull these carbs apart 2 or 3 times before the gaskets have to be replaced.

Most of the trouble comes from gunk, dirt, trash in the seats and bowls.

Pull it all apart spray insides with can carb cleaner, soak main body and air horn (with gasket, floats, needles and seats removed) in a pan of gas, blow passages out with compressed air and put back together

naf

iTrader: (7)

Before taking the carb apart put a fuel pressure gage on it and observe the pressure as it fails.

If the fuel line, especially the return, has been boogered with the conversion then I would expect the symptoms you describe.

Transam.82

That would mean...replace the line? I know lines were rerouted away from the headers, but the shop said it would still work fine.

naf

iTrader: (7)

It's vital that the return line remain functional.

Irregardless, hooking up a pressure gage is a no brainer.

Shop?

Transam.82

I tried doing the 388 conversion my self, but when I moved to Waco for school I couldn't keep working on it. My 'rents had it taken to a shop to finish it, as they had the garage I was working it. They did it as a gift/favor, but its turing out to be more work.The engine was built already, all they did was install it and the trans.

Transam.82

So put the pressure gauge before the carburetor but after the regulator?

naf

iTrader: (7)

Yeppers

Transam.82

Thanks, I will get to this after finals.

Night rider327

iTrader: (13)

Yep test with gauge after the reg.,. I normal just do a quick 3/8" barb'ed T and rubber fuel line right at the carb's inlet.

You want 5 to 5.5 psi. Lower than 5 psi is no good and more than 5.5 psi can push the needles out of the seats on edelbrock carbs.

What elec. fuel pump was used on yours? This could also be part of the prob. Like if that used one of the little part store in line elec pumps, or even a good aftermarket pump but mounted it wrong.

Also what fuel pressure reg. was used?

Transam.82

I have no idea what fuel pump it is, I've never messed with it. The pressure regulator is a Holley. Is there an easier way to get to the fuel tank besides dropping it? Also anyway to test my regulator?

naf

iTrader: (7)

Return regulator?

Transam.82

The fuel regulator. If the relief valve can be adjusted, it could be set too low.

Night rider327

iTrader: (13)

The holley reg (depending on model) will not work with high pressure TBI or TPI in tank elec fuel pumps.

You might want to look under car and make sure you don't have a holley red or blue pump mounted in line on fuel supply line.

Yes you can cut an area out of the floor pan above the tank, then cut the fuel lines and pull the sender/pump out... That or dropping tank is the only two options. I cut the floor to get to mine. Be very careful if you cut, the tank is only 1/4" to 1/2" below the floor. I used an air powered 3" cut off tool with a 3" cut off wheel

Transam.82

Do you have a picture of that area or something I can reference? If I cut I want to make sure it right before I cut.

Night rider327

iTrader: (13)

Sure thing man. Here you go.

I taped out my cut lines 1st
https://www.thirdgen.org/forums/atta...icture-102.jpg

Then made cuts on left, right and front. Did not cut the rear.
https://www.thirdgen.org/forums/atta...icture-103.jpg

Cut the fuel lines using a tubing cutter, and cut the sender/gauge/pump wires
https://www.thirdgen.org/forums/atta...icture-104.jpg

Used rubber fuel line and hose clamps to hook lines back together. You could flare them and use fittings if you wanted too or even use compression fittings to join them back.
https://www.thirdgen.org/forums/atta...icture-108.jpg

I then folded the metal back down, and used some scrap I had laying around to rivet the metal back in place so it would hold done flat and flush
https://www.thirdgen.org/forums/atta...icture-111.jpg

Do not go cutting or dropping tank untill you check the fuel pressure and looking under car for aftermarket inline pump.

If you have the std. holley fuel pressure reg (like this one http://www.summitracing.com/parts/hly-12-803/overview/) with an in tank elec pump, the reg is the prob.

Those can only handle 8 or 9 psi max inlet pressure and stock in tank pump puts out 20+ psi.

If you have one like this http://www.summitracing.com/parts/hly-12-846/overview/ it can't turn the pressure down enough for a carb

This is the go to unit for these types of swaps http://www.summitracing.com/parts/maa-4307m/overview/ it can handle the higher pressure of the stock pump and can turn down as low as 4 psi so you can set your 5 psi to work perfect with a carb