I seem to have a fuel delivery problem...

[Grec]

A bit of background:

1973 Challenger with a '68 440HP. 4-barrel Holley. Mopar high-rise intake. 915 heads. 4-speed.

Car was has always been a bit touchy as far as nailing the gas from a dead stop. I've found it best to ease into it. If not, she tended to bog down. It was worse when she was cold, but it happened even it she was warmed all the way up. Also, she tended to feel a little winded when you'd get up into the higher RPMs. Not having any prior experience with a Chrysler 440, I was never sure if that was just a charactistic of the engine or not. In between, though, she felt nice and strong. A good chirping of 2nd gear was never a problem. :-)

She's been like that since I got her a few months ago.

Just a couple weeks ago, though, she started stalling on me.

It tended to happen when I was coming up to a stop light and let off the gas, but it also happened a couple times on take off. She would stall and then have a bit of trouble getting up again. I'd have to wait a minute of two, give it a few tries and eventually she would fire back up.

That ended last weekend when she stalled for good. I was unable to get her to crank again.

I've got gas in the car and I have spark.

I'm thinking it is probably either:

Clogged fuel filter
Dead fuel pump
Worn down fuel pump rod

That said, I have no idea what to look for when I pull these parts to tell if they ar shot.

Anyone have any advice?  Also, if my description of her problem brings something else to mind...

[422STROKER]

I had this prob w/my holleys, check the float adjustment on the carb to see if it's too high?  It does sound like a lean bog off the line.  Dirty needle/seat maybe.  Just throwin out some ideas for you here.


Tom

[Bullitt-]

Grec, I'd start by checking for fuel getting to the carb. Just disconnect the supply hose & put it in a container, turn the motor over a few seconds & see if you get at least a cup of gas. If not backtrack removing the filer, remove the supply line to the pump & see if you can siphon from the tank(could be a clogged tank fuel sock), wherever the problem disappears the last item removed is probably the problem. If there is adequate fuel getting to the carb, it probably is the carb.  One more issue is bad gas, maybe water in the fuel, you will be able to see that with the first test.

Here is a good article to help understand how a carb works.
http://www.chevyhiperformance.com/techarticles/83118_carburetor_basics/

[Grec]

Gotcha.

Thanks, guys... as always. :-)

[Chryco Psycho]

I keep finding bad fuel pump push rods , that being said you need to pull it out of the block , there is a pipe plug under the fuel pump , just remove that & the rod will slide right out  , the push rod has a raised center protion & is smaller diameter on each end , both ends should be equal length if they are not the rod is worn down & needs to be replaced But this may not cure the problem as often the cam get damaged as well , youy can try a new pushrod to see if it works if not you will need a new cam or you will have go to an electric fuel pump
when installing the push rod coat it with thick grease  , it will help it stay up log enough to get the fuel pump mounted under the pushrod , if it slides down it will block the installation of the pump 

[Grec]

Well, here's to hoping it isn't the rod. Sounds like that would be a bit of a pain.

On the bright side, it would make for a good opportunity to switch in a hotter cam!  :-)

[MEK-Dangerfield]

I had a worn rod once that took me forvever to figure it out  . It looked good, but darned if it wasn't 1/4 inch shorter than the new one I bought. Yep, it is a little bit of a pain to remove and replace the first time. Just have heavy grease or Vasoline coated on the one end to hold it up in the block while you re-install the fuel pump.

If you take Bullitt99's advice, and see if you get nice gas flow into a cup while someone cranks the engine, then we can tell if it's the carb, or if we have to work backwards down the line. The fortunate thing is the filter, fuel pump, and pushrod are all pretty cheap fixes. It would be nice if you had a mechanical fuel pressure gauge to place in your fuel line to see what kind of pressure you have now. Good luck, and let us know what you discover.

  Mike

[426 pentastar]

Use a vacume/fuel pressure gauge to see how much fuel pressure you have coming to the carb,also low float level will couse this,if its a holley you may need to change the power valve/step up.That depends on the vacume your motor is making.Power valve will couse a bog but run well in mid-range rpm then lay over at higher rpm.

[chevyconvert]

take out the filter and back flush it to see what's in it.
I was biting the bullet and rebuilding the six pack carbs.
Didn't want to recontaminate the new carbs and keeping in mind these cars are 30+ years old, under closer inspection:
1. the sending unit was shot. only way gas was getting through it was the filter sock was split
2. the gas tank had crud in it and was corroding
3. etc.etc..

So now with a new gas tank, sending unit, fuel/vapor/return lines, fuel filter, fuel pump, and vapor canister to go along with the six pack rebuild, my Fuel side issues should be over for good.
Now I'm hoping (not finished yet) it's just fresh fuel, sta-bil, and

Point is that the fuel side is only as good as the weakest link.

[Grec]

Agreed. That old weakest link thing.

Well... the good news is that my fuel system seems to be working from the tank to the filter, as I disconnected the filter and dumped the line from the pump into a pan while turning her over.

After around 10 seconds of turning I had about a cup of water-free gas.

The filter was definitely a bit dirty so I'll be replacing that. If that doesn't fix 'er it'll be on to the carb.

[Grec]

Woohoo! A new fuel filter and fuel lines (one looked a bit collapsed and the were all splitting) did the trick! :-)

Still having a bit of a lean issue with the carb, but she's running... and better than before she konked out.

Thanks for the help, guys!

[Bullitt-]

 

[MEK-Dangerfield]