Mechanical fuel pumps

[HotRodPC]

Thanks for the info guys... I'm wondering if fuel pressure is why it dies out when i slam on the gas. Its a new crate 350, timings set, carbs tuned, no vacuum leaks.. so o was gonna try a new guel pump..im stumped. I havent checked fuel pressure.. hmmmm

OK, so you're not even sure you need a fuel pump but you're going to change it???


So this happens when you nail the pedal? I'm not thinking it's a fuel pump. So long as there is fuel in the float bowl, then gas should be there. I'd be more apt to take a look and suspect the accelerator pump in the carb. Maybe even just an adjustment on the accelerator pump.

 

[DavesJimmy]

OK, so you're not even sure you need a fuel pump but you're going to change it???


So this happens when you nail the pedal? I'm not thinking it's a fuel pump. So long as there is fuel in the float bowl, then gas should be there. I'd be more apt to take a look and suspect the accelerator pump in the carb. Maybe even just an adjustment on the accelerator pump.

I got the fuel pump off craigslist when i bought the crate engine i just never pit it on cause of the differences in the number of connections... anyway that carb has 3 different settings for the accelerator pump i tried all 3. None worked pr made it a little better. So i took it to a shop and had them rebuild and tune it.. still didnt fix the problem ..

 

[hatzie]

Slobberjet to the rescue, I think not. Lol

I'm a fan of the Q-Jets. Not a performance carb but they've been dead reliable for me on a range of engines including a couple Chryslers that I still own. I have one on a 78 G20 van, 1969 Dodge Polara 383, and I'll be installing one on a 383 in a 1966 Dodge W200 4x4 pickup. The Rochester Quadrajet is far less fiddly than the Eddy and Holly offerings.
Yes, you can make the Eddy and Holley carbs work almost as well but I don't like screwing around with them for an entire weekend changing springs and jets to make em happy. The only reason the FE390 in my 72 F250 still has a Holley is it's the original carburetor that it left the line with in 1972. My 383 Chryslers had re-man Carter BBD carbs with the wrong part numbers for their year so both engines got spreadbore 4barrel manifolds and Rochester Quads.

 

[Rusty Nail]

Y this thread no haz picks?

 

[HotRodPC]

I got the fuel pump off craigslist when i bought the crate engine i just never pit it on cause of the differences in the number of connections... anyway that carb has 3 different settings for the accelerator pump i tried all 3. None worked pr made it a little better. So i took it to a shop and had them rebuild and tune it.. still didnt fix the problem ..

Ok, so if a shop rebuilt it, then it's safe to say the accelorator pump isn't the problem. There's no signs of leaking around it at all. If I'm understanding right about the complaint you mention, it just doesn't reason to me that it's the fuel pump. The float bowl should have fuel in it when you stomp the gas pedal and the accelerator pump is what makes sure to pump a squirt of fuel when you stomp on it. Fuel pressure shouldn't be an issue. Fuel Injection, fuel pressure matters. Not enough pressure, the injectors won't open. Carb for the most part is pretty much a gravity flow.

So does it really sound like it's running out of fuel or is it a stumble then catches up with itself? I think I'd take a look at timing. The Vac advance plate, the counteweights for the mechanical advance and things of that nature just for ***** and giggles.

 

[HotRodPC]

Y this thread no haz picks?

It does. You commented on that fuel filter with the return line built into it. I too have never seen one like that and found it interesting. I like it. I may have a use for that someday.

 

[yevgenievich]

I had edelbrock do similar. Ended up two things, the vacuum actuated enrichement spring and the vacuum advance

 

[Rusty Nail]

Lol...ya that's great and all but I guess my dumb ass keeps thinking the OP will post some pix of his edelbrock junk. He's prolly embarrassed, I would be.

For sale! Edelbrock 1406 with electric choke. $100!

xc_hide_links_from_guests_guests_error_hide_media

 

[HotRodPC]

Everyone has their preference. Some people even like the junk knowing it's junk, but it's something they know how to work on so they keep it. I've seen that many times. All 3 of the big names have a purpose IMO. For a DD, I think the well and properly built Qjet is best. That means, epoxied well plugs and bushed throttle shafts. You can work over an Eddy and make it good too. I don't care for Holleys since they tend to blow power valves fairly easy, but for drag racing, Holley is probably one of the best of the 3.

 

[Snoots]

I wish I had all the money I spent on Holley power valves back!

I know some people like Holleys' and that's ok.
But they gave me a BIG headache and I spent too much time trying to get it right and not on the road having fun.

 

[DavesJimmy]

Ok, so if a shop rebuilt it, then it's safe to say the accelorator pump isn't the problem. There's no signs of leaking around it at all. If I'm understanding right about the complaint you mention, it just doesn't reason to me that it's the fuel pump. The float bowl should have fuel in it when you stomp the gas pedal and the accelerator pump is what makes sure to pump a squirt of fuel when you stomp on it. Fuel pressure shouldn't be an issue. Fuel Injection, fuel pressure matters. Not enough pressure, the injectors won't open. Carb for the most part is pretty much a gravity flow.

So does it really sound like it's running out of fuel or is it a stumble then catches up with itself? I think I'd take a look at timing. The Vac advance plate, the counteweights for the mechanical advance and things of that nature just for ***** and giggles.

Im going to check the distributor. It does stumble then die! Im sure timeing is set right ill check internals, rotor, springs, vacuum advance ..etc... thanks hotrod.

 

[hatzie]

Im going to check the distributor. It does stumble then die! I'm sure timing is set right I'll check internals, rotor, springs, vacuum advance ..etc... thanks hotrod.

Big cap HEI aren't difficult to rebuild. All of the electric parts are available from AC Delco... the mechanicals can be had aftermarket and that's mostly just springs and plastic bushings. Some folks have had good luck with the Skipwhite units... I'd just re-work the GM unit.

The biggest problem I've found with old distributors is the end play between the gear and the housing. The second biggest are the advance weight bushings.

 

[Battlac40]

I had similar problems and it was all due to timing.
Ps the eddy is always going to piss you off, but it looks pretty, and everyone will always say " What a bad ass carb bro "
Whalst you are crying on the inside and saving up for sniper efi or a dominator&bigblock.

 

[HotRodPC]

Yep, What they said up there !!!

 

[Snoots]

The biggest problem I've found with old distributors is the end play between the gear and the housing. The second biggest are the advance weight bushings.

And the springs. OMG, was it this set or that one or did I swap the two into separate groups?