Voltage drop and electric fuel pump question (2 Viewers)

[69FJ40NJ]

I have a 69fj with a sbc350, automatic, HEI dist.

I replaced the HEI coil about 8 months ago, and have been driving it since with no issues. Two weeks ago I pulled into the garage and next time I tried to start it, it would just keep cranking. Tested wires, 12+ volts at battery and 7+/- at the coil. Has new plug wires, plugs, now a new HEI distributor. I guess my next test is take out the ignition and test the wires there, any other suggestions?

Also, my rig has a electric fuel pump. The mechanical pump has a block off plate. Is there a typical reason in a SBC conversion why this would be done? It is not a 'worked' motor as far as I know. I would really like to go back to a mechanical fuel pump so I have one less future electrical issue to worry about.

Thanks for the help!

DM3

 

[427060]

7V at the coil? Shouldn't those stop working at 9? I wonder if you are losing voltage between the battery and distributor.

 

[lcwizard]

Depends how "old school" the 350 is and the way it was wired.
Back in the carburetor days, the voltage to the coil was taken off a now never used terminal on the starter.
That terminal supplied voltage to the coil. However if this engine had a points style distributer at one time,
some were wired to have 9v to the coil at run but 12v at cranking..
Or you might just have a week battery. You need to test the battery voltage while cranking to see if there's a
significant drop while cranking. That would indicate a bad battery. Your local Oreilly or Autozone can test that
with their battery tester.

 

[69FJ40NJ]

So I just wired directly from the battery to the dist and it fired right up. I was told by a shop to search 70 71 Chevelle when looking for parts.

 

[charliemeyer007]

So how old is your ignition switch? They do go bad, I think I'm on my 3rd one for my 72. Disconnect your battery then start cleaning every wire connection plug. Look in both ends, use some spray and a small scraper to make sure the contacts are clean and bright, a little dielectric grease will help them stay that way. Look carefully at the wire where the connections are crimped - corrosion can crawl up the wire under the insulation. A 30 cal. bore brush works nicely on the fuse box tabs for the fuses.

 

[69FJ40NJ]

Ignition switch looks old, my key looks like an original.

 

[B y r o n]

GM used HEI distributors on a few models in 1974 but became the standard in 1975.

Electric fuel pumps started to be used in the 1970's. Some of the reasons were they could be mounted just about anywhere, including in the fuel tank, and they were also considered more reliable and lasted longer. I'd say if yours is working fine leave it alone, don't try fixing what isn't broken. You may want to find out what make and model it is so you can find a direct replacement. Easier than trying to mount and wire another brand when your not at home with all the tools available.

 

[69FJ40NJ]

I figured if i replaced the electric pump with a mechanical pump, I would avoid that issue.

 

[pb4ugo]

You need 12volts and a 12 or 14ga wire going to a GM HEI dist. I've always run a mech pump snd a HEI dist. I prefer a return line too. If your going that direction you should pull the block of plate and see if the push rod is still there. Later blocks might not be drilled for the push rod.

 

[pb4ugo]

Where are you getting power for the coil?

 

[69FJ40NJ]

Update: replaced the coil wire, it was spliced 5 times. Rig fired right up.