Fuel pump problem?

[Yoda]

After I put in my Petronix ignition about two months ago, the car ran great. A few weeks later I started having some trouble right after startup. I've tweaked the carb a bit, and replaced the plugs and ignition wires, but can't seem to improve things. The car starts right up every day and revs OK in park, but as soon as I put it in gear, and give it some gas, there is terrible hesitation and sometimes stalling. If I come to a stop or slow down, this repeats for the first 2-3 minutes that the car is running. If I get past the "bad spot" in my acceleration it runs OK. It feels a lot like bad points, but as I mentioned, I upgraded to the Petronix so there are no points.

After the first 2-3 minutes, everything is fine, however I'm starting to notice that the car trembles a bit if I really stomp the accelerator. If I accelerate at a more steady pace, the car is very responsive and feels 'strong'.

I'm not sure, but it 'seems' that making my carb mixture a bit richer helps things a little at start up. I don't think it is the electronic choke because I pretty much have the same issue whether the choke is open or closed and on both cold and warm mornings.

I know this could probably be a lot of things, but my gut is telling me that maybe my fuel pump is not up to snuff.

Does this sound reasonable? Any other ideas?

[boaterbob]

Yoda, I put Petronix on my car it ran fine. Then i put the Petronix coil on and had the problem you have. Went back to the regular coil from the auto store no more problems. I left the rest of the petronix alone.

[boaterbob]

Check for vacume leaks also

[Yoda]

So do you have a stock coil getting power after going through a ballast resistor and separate power for the Petronix or are you running a standard voltage non-resistor coil?

[boaterbob]

Stock coil

[Yoda]

Well, I put a standard voltage coil back on my car and still had the bad hesitation for a few minutes after startup. I'm using a coil with a built-in resistor because I've completely bypassed my transistorized ignition and therefore am not using the ballast resistor or a resistor wire.

When I put a vacuum gage on the car, its pulling a very strong vacuum so I don't think there are any leaks. New plugs, new wires, new coil, Ignitor II. I'm stumped.

It seems that my choke/high idle are coming off very quickly (its about 60 deg F in the mornings here now). Seems like I'm at low idle by the time I'm at the end of my driveway, so maybe I need to tinker with that a bit. Even though it is warmish here, I don't think the choke/high idle should come off until the car has warmed up a bit.

Any other suggestions are much appreciated.

[tbird5866]

Why don't you just check the fuel pump for pressure and volume? Thjat would be standard procedure.

[Yoda]

Finally brought the car to a good mechanic and discovered there was a two-part problem:

1. vacuum advance on the distributor was shot
2. my new Holley carb came from the factory with the rear float cranked all the way in so that no fuel was getting to the rear of the carb.

Turned out that after fixing the vacuum advance, my timing was right on (about +6 deg) and that my entire ignition system was firing well. My mechanic jetted the carb a bit and tweaked a few things here and there and now my otherwise stock, unrebuilt engine really goes. Roads were a little slick today so it wasn't much of a challenge, but I think the car will burn rubber on a dry day (not that I plan to do that very often).

$160 later and all is finally well. Wish I had brought it to a pro six months ago!