Phenomena at Acme

[70NPORT]

Opinions please.........

After making a pitstop this morning at the local market place I got in and tried to start the car. No deal. It turned and turned and turned. So rather than killing my battery I popped the hood and did a methodical inspection in attempt to find the problem.

Bingo.

No gas getting into the carb, so the motor is just sucking down air. The fuel pressure gage indicated no fuel pressure whatsoever. There is usually around 5 or 6 psi for a good long time until the car is cold and sat for awhile. I was only in the market about 45 mins.

Want to take a shot at happened here?

Fuel pump is stock mopar 383/440 mech fuel pump. Its only 3-4 years old. It got the car started again by litereally pumping the pedal 15-20 times. It sort of stumbled to igniting and then running and then ran normally on the way home.

Vapor lock, bad pump? I'm not sure how to call it at this point, esp. since the original fuel pump lasted almost 45 years. I would think I could expect at least half that amount from the newer one.

 

[commando1]

What was the air temp, Gary. Trying to rule out vapor lock or not.

 

[1978 NYB]

Thermostat......LOL!

Did it start after the engine cooled down?

 

[detmatt]

Check the length of your rod.

 

[commando1]

Ouch, Matt. Go to your room.

 

[70NPORT]

What was the air temp, Gary. Trying to rule out vapor lock or not.

It was very warm out at the time Stan (78), but not "summer hot" yet if ya know what I mean.

 

[70NPORT]

Thermostat......LOL!

Did it start after the engine cooled down?

It started before cooling down. It only sat parked for a bout 45 mins or so. So it was still hot.

 

[70NPORT]

Check the length of your rod.

I hoping there are no issues there. lol.

 

[70NPORT]

While the hood was up I had the air cleaner off and while staring down the carb throat and hand actuating the throttle I could see that barely any gas was squirting out from the nozzles. The carb is on a 1/2" thick wooden spacer. I used to get vapor lock all the time before putting the spacer underneath the carb.

 

[detmatt]

I wasn't really kidding with my suggestion, that's exactly what I went through repeatedly. Sometimes it would do that but others it would fire right up, it had me scratching my head for a long time. Gary, I know you drive your car regularly and that's all the more reason to check it and at least rule it out.

 

[70NPORT]

I wasn't really kidding with my suggestion, that's exactly what I went through repeatedly. Sometimes it would do that but others it would fire right up, it had me scratching my head for a long time. Gary, I know you drive your car regularly and that's all the more reason to check it and at least rule it out.

Matt I believe I understand what you are saying....the fuel pump is not getting full stroke and therefore adequate pressure is not being achieved? This can be an intermittant problem?

 

[53ryder]

I wasn't really kidding with my suggestion, that's exactly what I went through repeatedly. Sometimes it would do that but others it would fire right up, it had me scratching my head for a long time. Gary, I know you drive your car regularly and that's all the more reason to check it and at least rule it out.

You talking about that rod that hits the tongue of the fuel pump as the engine turns over?

Glenn

 

[detmatt]

It was for me and on its own I think the system can deal with it but it makes it more sensitive to things like vaporization due to higher temps. If the rod was not worn and you're boiling fuel in the carb it doesn't take too many cranks to fill the bowls back up and start the car. If this is happening and your rod is getting shorter it's going to take longer to fill the bowls and start the car.

 

[bluefury361]

I'm surprised no one thought to check the filter.... It's an old car. I carry a spare filter everywhere I go.

 

[70NPORT]

It was for me and on its own I think the system can deal with it but it makes it more sensitive to things like vaporization due to higher temps. If the rod was not worn and you're boiling fuel in the carb it doesn't take too many cranks to fill the bowls back up and start the car. If this is happening and your rod is getting shorter it's going to take longer to fill the bowls and start the car.

Guess this means pulling this pump.

 

[70NPORT]

I'm surprised no one thought to check the filter.... It's an old car. I carry a spare filter everywhere I go.

Filter is clear but since I'm gonna have the car down for a couple days soon good excuse to change it out for a new one.

 

[bluefury361]

Filter is clear but since I'm gonna have the car down for a couple days soon good excuse to change it out for a new one.

Theres a "sock" at the end of the pick up in the tank also. You might consider checking that too Gary.

 

[bajajoaquin]

I wasn't really kidding with my suggestion, that's exactly what I went through repeatedly. Sometimes it would do that but others it would fire right up, it had me scratching my head for a long time. Gary, I know you drive your car regularly and that's all the more reason to check it and at least rule it out.

This was my thought when I saw the thread. After reading your issues and resolutions, this was my guess.

Matt I believe I understand what you are saying....the fuel pump is not getting full stroke and therefore adequate pressure is not being achieved? This can be an intermittant problem?

Yes, that's what he's saying.

I'm thinking back to the discussion about my hard-starting problem when hot. There was a comment that it was the carbon build up in the manifold that was making it hotter. That may be true. But if my rod is too short (heh) maybe the fuel pump just isn't refilling the bowls fast enough.

I get some pinging under load on the freeway, too. I wonder if my timing isn't so advanced, but the carb is leaning out..... Hmmm.

Looks like I'll be checking that.

 

[bluefury361]

A simple fuel pressure check will answer that.

 

[Wildaugust]

I was thinking that something had temporarily clogged the carb jets, but you said your pressure gauge showed no fuel pressure.

It does sound like it may be a clogged filter. I had a clogged in-tank filter (sock) that would allow me to drive for ten or fifteen minutes before the engine would die. Then I'd have to wait ten minutes or so, before I could start my engine, only to repeat the entire scenario all over again.