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fuel pump
https://slantsix.org/forum/viewtopic.php?t=35850
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Author:  urbanyi1 [ Mon Jun 15, 2009 1:17 pm ]
Post subject:  fuel pump

I have a 1976 Plymouth Volare and it has been running ok, but when you push the gas pedal down it sometimes wants to stall. Now today it will not start and I don't smell any gas in the carb. Do you think it is the fuel pump? That is what is sounds like to me. Help!!!

Author:  Andy's GT [ Mon Jun 15, 2009 1:37 pm ]
Post subject: 

did you check the filter? do you know the history or the car? ive had a LOT of fuel related issues with my dart since the PO let it sit in a barn for 9 years with a full tank of gas, ive redone the entire system but had the old tank in time before this one that i was able to drive it, and after i replaced everything else fuelwise, it stalled on me because my carb (which i rebuilt when i went to supersix) had picked up too much crap from the old tank. so you could have a clogged filter, or pump like you thought, or it could be all sorts of fun stuff like mine :/ filter would be the easiest and cheapest thing and a good place to start i would think, although it might be more then that. good luck!

Author:  65Dodge100 [ Mon Jun 15, 2009 1:40 pm ]
Post subject: 

It’s happened before so check that this isn’t the problem.

Your fuel filter could also be clogged.

You can open your choke and look into the carburetor to see if the accelerator pump is squirting gas.

Check your oil and see if it smells like gas or if you have way too much oil. That would mean the diaphragm in the fuel pump has ruptured. I don't think I've ever had a bad fuel pump that didn't leak somewhere.

Danny

Author:  Andy's GT [ Mon Jun 15, 2009 1:46 pm ]
Post subject: 

yeah, my stock one sprang a leak 4 hours from home one time, opened the hood at a gas station full of perfectly rebuilt mustangs owned by people with much more money than me, to see that. :oops: better out than in? eh? eh?

Author:  urbanyi1 [ Mon Jun 15, 2009 3:20 pm ]
Post subject:  Fuel pump

I changed the fuel filter a couple weeks ago, and when pumping the accelerator I can't see or smell gas in the carb. It has a full tank of gas :D I haven't checked the oil to see if it smells like gas, I will do that. I'll let you know the outcome.

Thanks for the suggestions.

Author:  Mister_Perkins [ Mon Jun 15, 2009 6:46 pm ]
Post subject: 

sounds like a bad accelerator pump. If you look down the throat of your carb and pump the throttle and you dont see a squirt of gas then your accelerator pump isnt working right. probably a ripped cup but further inspection is needed. Pull the top of the carb off and check the accelerator pump cup. Make sure your floats are adjusted right and re-assemble. If it idles alright but cuts out when you step on the gas, no gas squirting into the throat of the carb when you pump the throttle its probably the accelerator pump like I said.

Author:  urbanyi1 [ Mon Jun 15, 2009 7:07 pm ]
Post subject: 

When it was running it would idle great, but it did stall when the accelerator pedal was pressed, which could be the accelerator pump, but right now it will not start. Like I said earlier, I don't think there is any gas getting to the carb. Or does the accelerator pump suck the gas through the pump?

Author:  jdog [ Mon Jun 15, 2009 7:47 pm ]
Post subject: 

what about a sticking needle valve if its stuck close

Author:  65Dodge100 [ Tue Jun 16, 2009 3:44 am ]
Post subject: 

Another test for the fuel pump is to take the fuel line off the carburetor, stick it down in a jar and crank the engine over to see if it pumps fuel. The way yours is acting it should be pumping almost nothing if the pump is the problem.

If it is pumping I’d start looking at the carburetor then.

Danny

Author:  Mister_Perkins [ Tue Jun 16, 2009 1:39 pm ]
Post subject: 

if your running rubber lines to your carb, make sure a piece of rubber didnt break off and jam into the inlet on the carb. this happened to my truck and it wouldnt run at all. I pulled all the lines off and I was running fuel pressure test over and over and was getting 4.5 constantly but it wouldnt push it into the carb because there was that little piece of rubber holding the fuel back. Try running an inline fuel pressure gauge on the lines before the pump and after the pump. /6 is supposed to be between 3.5 and 5 Psi. if its any lower then you probably either have a weak pump or a vacuum leak (cracked fuel line). I agree with Doc on not enough fuel pressure. Also.. Might want to try grabbing an electric pump and testing that hooked up in place of the fuel pump. Depending on the motor status and mileage the camshaft might be wore down and the pump could be pumping less than 3.5 Psi of fuel pressure. I had that problem on my truck too. Currently I am running just an electric fuel pump next to the tank and I am happily getting 4.5Psi.

Recap:

1. Check/replace cracked fuel lines (cracked lines are most likely a vacuum leak)
2. Run a fuel pressure gauge with a T block to hook it up
3. Try an electric pump
4. Pull the top of carb off and inspect needle and seat, and accelerator pump cup.
5. Make sure to pull the main feed to the carb. and make sure the inlet is clear as well.

Good luck, I hope you can figure it out!

Gauge will look something like this. Has quick connects and all you need is a T style fuel block to split it off to the gauge.

Image

This is what it looks like with it all hooked up:
Image

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