Fuel questions HELP

[Rent-A-Racer]

1) How much fuel should one see in a clear fuel filter when car is warm and idling?

2) Besides a fuel delivery problem, what else would cause a car to idle fine, but sputter and back-fire under acceleration?

Thank you for any help you can provide!!

 

[bnickel]

1) should be almost full at idle and you should see fuel flowing through the filter at a fairly slow rate while at idle, you should also see bubles
2) could be anything really. ignition: weak spark, improper timing, crossed wires. fuel: delivery problem-fuel pump, clogged filter, etc. float level set wrong, bad power valve or accelrator pump.

if you think it is a fuel delivery problem, with the engine running bring it up to a good steady rpm around 1500-2000 and watch the fuel filter to see if the fuel is flowing through it well and it should be flowing pretty good at 2000 rpm, if that looks good then check the float levels and adjust as needed. if you still have problems get back to us with as much info as possible, such as is it falling on it's face at any rpm past idle, in gear or out, what rpm range does it start at, check the plugs are they wet with gas or do they look ok, that kind of stuff, let us know

 

[6Stang7]

I would saycheck you timing, but more importantly, your vacuum advance.

-Shaun

 

[Rent-A-Racer]

Thanks for the help guys!! I replaced the vaccum advance, all the line is new, as is the carb. fuel lines, plugs, rotor (Mallory pointless), cap, wires, and fuel filter. I'm installed an electric fuel pump (pusher style) in case it was a fuel starvation problem. The plugs look like they should when pulled

bnickle- the symptoms occur only when car is in gear, under medium/light acceleration. (it sputters/stalls and has backfired a couple of times

 

[6Stang7]

Hmmmmmm, well I would still check your vacuum advance (use a timing light to make sure it bumps the timing up the correct amount at a given RPM) and timing. This really sounds like an ignition problem.

-Shaun

 

[69stang351]

1) should be almost full at idle and you should see fuel flowing through the filter at a fairly slow rate while at idle, you should also see bubles

yes, but not too many bubbles, I saw too many because my fuel was boiling before it got into the carb... i had to put wooden clothes pins on the fuel line running into the filter to act as heat sinks to cool down the fuel before it got in the carb... worked great!

 

[Rent-A-Racer]

I notice when I have the problems I've described, that the filter is almost empty, compared to when it's at idle (over half full) took it out today, it ran well for about ten minutes. then started to miss and sputter as described above. popped the hood, filter very low. Pulled the fuel line off the tank, and its seemed empty. I sucked on the line going to the tank pick up and got 60% air. I see no visual defects with the pick up /strainer or lines. THe car is full of gas! WHAT GIVES??

 

[6Stang7]

Do you have a mech. or elec. fuel pump?

Edit: Hahaha, you already answered that. I would check your fuel pressure at idle and at different RPM's.

-Shaun

 

[xoxbxfx]

is the filter dirty?? Sounds dumb but my car had the same problem. The sediment would fall to the bottom of the glass and it would get sucked back up onto the filter when you get on it and the car would starve for gas.

How do you have your pump wired up?? Is it possibly gettting grounded while you acccelorate? Not enough electricity or too much while accelerating causing the pump to stop?

 

[bnickel]

i guess i'm not understanding what you were saying. did you say you pulled the line from the from the tank to the pump, at the pump, or did you pull it at the tank? if you pulled the line at the pump and got air you probably have a rubber line somewhere between the pump and the card that is rotten. there are three total rubber lines from the factory between the pump and the carb. the on from the pump the the metal line by the shock tower, there is one that connects right under the driver side floor and the one at the tank pickup over the rearend. then you siad you have the electric fuel pump too. i'm assuming you have it plumbed with a ruber line on each end of it. i would start by replacing all of those and make sure they are sealed good, my bet is that will solve your problem. the only other thing i can think of is that that the filter sock on the pickup in the tank is disentegrated and causing a clog in the system there. let us know what you find out

 

[Rent-A-Racer]

thanks for all your input guys!! I'll keep you updated

 

[Rent-A-Racer]

THANK GOD!! I finally got the 'stang going! It was a pin hole in the tank pick-up tube. It only showed when I tapped one end and used commpressed air! well, after swapping parts for almost 2 weeks, I'm just glad to have it running right!! At least it wasn't anything major. My Dad always said "Boy, those old cars will nickle and dime ya to death!" He was right, but I still love 'em. I guess it's just the nature of the beast!

 

[6Stang7]

So true. Not only do they nickle and dime you to death, but you're never "finished" with them.

-Shaun