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Sputters and dies while driving.

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Old 02-20-2011, 10:18 PM
  #1  
Wildcat09
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Default Sputters and dies while driving.

I just recently bought a 74 mustang 2 under the impression that it just needed a carb rebuild. Which it did, driving it home it sputtered and had no power going up hills, crawled up most of them at about 15 mph. Got it home and rebuild the carb and it is still sputtering. Only now it sputters going up hill, or on flats. Not sure what could be wrong, vacuum leak, the electric fuel pump that was added or messed up on the rebuild. The odd thing is that it runs just fine when not in gear, also running a c4 tranny. Any and all help would be awesome. Thanks
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Old 02-21-2011, 12:22 AM
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sethalot
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could be a warped cylinder head. had a Chrysler conquest that acted just like that
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Old 02-21-2011, 12:32 AM
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Gun Jam
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I like how you said it only sputters now on flat ground or up hills LOL!

Sounds a whole lot like a fuel delivery issue primary to lack of fuel volume. Low fuel volume secondary to:

1) rusted and obstructed fuel line
2) Failing fuel pump
3) Plugged filter


Remove the fuel line from the carb and place in a large glass jar. Crank the engine for 3 to 5 seconds if there is less than 2 cups of fuel in the jar I'm probably right. If there is 1 cup of less i am right.

Having someone watch helps too the fuel should surge out of the line and splash out of the jar and the guy watching should say "whoa..whoa okay stop its getting everywhere" If it kinda pisses out of there after a while and takes its sweet time and is not real dramatic...you know what to do.

If you do find it to be fuel related I would just go back to a mechanical fuel pump rated at 6psi...The carter 120 GPH is a well built system... also since you have the electric system finding a way to check fuel pressure at the carb would be good...maybe the pressure at the reg is just too low...hell maybe its too high (anything above 6 psi is too high and anything below 3 might not give enough volume) The regulator its self might be bad too.

-Gun

Last edited by Gun Jam; 02-21-2011 at 12:38 AM.
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Old 02-21-2011, 10:34 PM
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Wildcat09
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Going to double check all the filters tomorrow, but don't know if it will help. Talked to a few guys at the ford dealership and they said could be the points, so I checked them, the wire running from the coil to the distributor condensor was spliced together, so I ordered a new one, don't know if that will help or not. Everyone I talk to seems to think it is the fuel system so I will double and even triple check it. As for a mechanical pump, how hard is it to install one, I believe this car had one but the guy replaced it with an electric and I think that could be part of the problem. Also is there any way to update the ignition system from points to the modern form?
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Old 02-21-2011, 11:59 PM
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Gun Jam
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not real sure what your fuel lines are doing but generally switching back to mech should be pretty simple.

Check the fuel volume as I described unless you start actually testing things and reporting back all these suggestions and ideas amount to precisely.... jack. We cant verified or eliminate possible issues unless you take our advice and you end up chasing ghosts when the solution to the problem was posted back a week ago.

Happy hunting.

-Gun
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Old 02-23-2011, 04:25 AM
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tx65coupe
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My first thought is trash in the fuel system too.
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Old 02-24-2011, 09:40 AM
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Wildcat09
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Pulled the fuel line off of the carb and tested the fuel like Gun Jam said to. Gas was rust colored and after letting the fuel sit for a few minutes there was quite a bit of rust that settled to the bottom. So I am guessing that the fuel lines are rusting out and thus giving me the problem. Does anyone know how many lines should be running from the tank forward, I want to say a main line and a return line. Also anyone know how many feet fuel line is needed to replace the old?
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Old 02-24-2011, 10:46 AM
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Gun Jam
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So was the volume of fuel unimpressive as well? As in: did it just trickle out of the fuel line?....I guess at this point that's a fairly mute observation because of the amout of rust you saw.

1) your carb is now full of rust as well and must be cleaned again

2) The rust has plugged any filter up that you have installed and the filters are not working very well if that much rust is passing though.

3) it only takes one grain of sand or 1 flake of rust to stick a float open in the carb and flood the engine or make it run like crap.

4) Because of the impressive quantities of rust coming out of that fuel line the entire fuel system needs to be replaced. The fuel pump impeller is probably beat up as it has a somewhat close tolerance between the case. The pressure regulator is probably sticking as its filled with rust mud. The fuel lines as you figured are full of rust and can not be cleaned so they must be replaced as well. MOST IMPORTANT the fuel tank is probably the source of the rust and must be replaced it can not be cleaned practically and new tanks are not expensive. Seriously you are looking at a 100% new fuel system minus the carb. Unfortunately trying to skimp on this stuff will only haunt you for as long as you own the car unless you want to be a world champ and clearing stuck floats every month or so its gotta be all new.

5) I suggest going to mech pump and eliminate the electric system, the regulator, and the pump. As I said that stuff is probably messed up anyhow and the mechanical pump will be more reliable, less expensive, and easier to install. These pumps are driven off a lobe that fits in the timing cover. On the drivers side near the timing cover there should be a plate that is held in with two bolts its kind of a diamond shape. That is your mech fuel pump mounting area. Remove that plate and see if you can see the pump cam its simply a round piece of metal that is bolted to the lower timing gear (I think) should be visible. If not you'll have to install one.

Good Luck


-Gun
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Old 02-24-2011, 12:54 PM
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Wildcat09
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Fuel lines aren't an issue, I just need to find out how long they are so I can get the correct amount of tubing. Filters and carb are also a non issue for me, but replacing the tank and pump are. I am working on a very low budget seeing as I am a college student, so what would you recommend doing to reuse the tank, it at all possible?
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Old 02-24-2011, 01:13 PM
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Gun Jam
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Well you'll have to pull the tank drain it and then attempt to inspect it. Maybe you'll be lucky and find that everything simply washes out and the inside is bright and shinny. Im guessing that its going to have small sections of bright and shinny metal with large pockets of rust patches on the bottom of the tank that probably are very close to rusting through and cant be cleaned.

Maybe you could find a good tank in a junk yard or something.

First step is to inspect the tank...I have zero experience with the 74s but its a pretty safe bet you'll have to drop the tank to get a good look at it.

-Gun
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