Is It The Fuel Pump?

[LyinBrian1]

1972 Dodge Dart Swinger. 318, Eddy 600, dual exhaust, automatic, suregrip 8 3/4, factory air,

Was having a hot start issue and after great advice from this site, it is a lot better. We took the advice of many, closed off the crossover vents, added a spacer, insulated the fuel line, made some carb adjustments and it was running great. Sitting at a light, no power brake and punch it and she'd light 'em up until...

had her at a car show where we had sat for close to four hours, she started right up and as a bunch of MOPAR guys were leaving the lot they were lighting it up so I decided to jump in and she stalled.

Started right up punched it again and same thing.

We brought it home and by the time we got home it was running great.

A couple of days later we started it up, drove twenty minutes to a friends and started looking everything over and it was running great. Chalked the tires and burnt out in his garage.

Three days later another car show and as we were leaving we went up a pretty steep hill and she stalled. Really didn't punch it just gave her some gas to make the incline.

Next week we went to a car show and I babied her and had no troubles but it was really bugging me so someone suggested I change the fuel filter.

This past Saturday it started right up and I drove to the parts store and as I pulled in their lot which has a slight upgrade, she stalled.

Bought the filter but didn't get installed. Later that night at a show we were talking with a couple of MOPAR guys and we explained the trouble and they suggested the fuel pump.

They felt like when she's sat there is no pressure. Run a while and everything is fine.

They suggested an Eddy EDL-1720. 6 psi.

Thoughts?

 

[dart_68]

Usually if it stalls right when you punch it it's a problem with the pump circuit in the carb.

 

[72bluNblu]

Honestly it sounds like most of your stalls were going uphill. What's the float level set at?

The other thing is, carbed engines need to warm up. If it sits for 4 hours and cools off and you just punch it from stopped you're probably not up to temperature. Obviously some combinations are more "cold blooded" than others, and it depends on your timing settings, carb tuning etc. But until the engine is up to temp you're not going to get full performance, it's not fuel injection. What kind of choke do you have on the car?

 

[diymirage]

Fuel pumps are go/no go
I would check the float level first
Then double check timing...and if all else fails, someone might suggest setting the sync ports

 

[AJ/FormS]

So what is your idle vacuum,and idle timing? and
is the Vcan working and plumbed to the spark-port? and
what are your cam-specs,and either; true compression ratio or cranking compression-psi?
and TC stall? and rear gear?

Because it starts right up, I think your pump itself is fine.
Because it usually stalls with throttle tip-in, this is lean-running; usually an accelerator pump issue.
Because it has also happened on other occasions, and associated with inclines, and no tip-in? , fuel-level in the bowl, is a good place to start.

But
because it always starts right up, AND is seems to always be associated with transitioning from idle/near idle, IMO, the fuel level is pretty close to perfect, and the A-pump itself, is probably OK.
Since you didn't mention an idling issue, or a change in idle quality; Ima thinking the low-speed circuit,the T-port sync,the fuel itself, and liquid fuel level are all OK.
That just leaves the pump-shot timing,it's quality, and it's linkage adjustment,and/or the idle speed, and/or......... the power valve system.
Of those, I would check the linkage first and then the PV system.
The pump must deliver fuel the instant the throttle-valve is tickled,however slowly.And the fuel must be "streaming" liquid fuel, not dribbling,or full of air bubbles.
The powervalve system, metering rods in your case, must be activated at about 10 inches of manifold vacuum. This can be varied downwards for a bigger cam that idles at less vacuum; but I find 11 to perhaps as low as 8 to be very driveable.

So I would check/adjust the linkage first, and then I would install a manifold vacuum gauge with a long enough hose to be viewed from inside the car, and then go for a ride. I would try to associate the issue with a particular manifold vacuum, and a particular throttle position, and a particular road-speed.If you can do that, perhaps you will discover that the PV system is tardy.More powerful springs will be the next change, and a new roadtest.But the pistons must stay down at idle! And if they come in too quick, fuel consumption will suffer. They must also stay down at 65mph under steady-state cruise; so check your vacuum at 65 mph. This is usually not a problem.

The Vcan may not become active until 15/20 mph or so. Because of this we often run a tad more idle-timing, and get the mechanical advance mechanism started as soon as possible perhaps as soon as 200 or 300 rpm above the idle speed.This will increase the engines very-low-rpm torque, and help cover this sometimes hard-to-solve issue.
I good results with the the following
idle timing from 8 to 16 degrees,(the smaller the cam the less the timing). But I try to get the advance system going by 1000 rpm and for it to be around 28* by 2800, 36 by 3600 or sooner.The higher the compression ratio, the faster it usually takes it. But some combos will detonate under load if it comes in to heavy or too fast.
If your idle-timing is too high,it will upset the T-port sync.If it comes in too fast, you may get detonation, especially in conjunction with V-can timing.
If the idle-timing is too low,or too slow; torque suffers and you may experience driveability issues.

So what is your idle vacuum,and idle timing? and
is the Vcan working and plumbed to the spark-port?,and
what are your cam-specs, compression ratio or cranking compression-psi? and TC stall? and rear gear?

 

[nm9stheham]

Has it been hot each time this happened? And which Ashland are you at...KY?