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350 Start and Stalls

  
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350 Start and Stalls

 
gcpontiac73 gcpontiac73
New User | Posts: 3 | Joined: 08/10
Posted: 01/12/14
08:23 PM

I have a 73 Lemans 350. Had trouble getting it started for a while figured out it was the points. I swapped them out for an Pertronix Ignitor unit and bypassed the factory resistance wire with 12 gauge wire and the car ran great for months.

Recently the car starts and stalls. I sprayed the carburetor with brake clean started up then stalls.

I had the battery trickle charged. O'Reilly's always says the battery is no good. Left it over night. Hooked it up car cranks fast, starts and then stalls.

Amps light in cabin goes on when it stalls and Water light

Fuel issue when it stalls? Do I need to pour gas down carburetor? I'm thinking so.

Alternator tested and good. Only viable culprit would be the BAD BATT DIAGNOSIS AT PARTS STORE

STARTER CRANKING POWERFULLY AND CAR BATTERY HAS NOT DIED.

What do you guys think?  

ddemello ddemello
New User | Posts: 15 | Joined: 01/14
Posted: 01/12/14
09:43 PM

maybe the fuel pump is bad? maybe the fuel filter is plugged? maybe the rubber hoses are old and leak? maybe the carurettor needs to be rebuilt?  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 447 | Joined: 11/13
Posted: 01/12/14
10:21 PM

Hi,

What carb is it EXACTLY.



FUEL STARVATION- When it stalls/dies, do NOT pump gas or try to start it again.

Look in carb

open throttle only 1/2 way at moderate speed

you should see two fairly strong, thin streams of gas

if you have gas it is not likely starved for gas, in which case:

check float level, might be flooding due to a bad needle and seat or sunk float.

if that's ok it might be a leaking power valve if it's a holley. if carb is old just replace it. it most likely takes a 6.5, there will be small numbers on it telling you what it is.



2. PERTRONIX - They have an unusually high failure rate unless it is the III model, I would try the old points plate.  

wayne712222 wayne712222
Moderator | Posts: 235 | Joined: 10/13
Posted: 01/12/14
11:46 PM

you have SEDIMENT in the fuel system.   its keeping the check valves in the fuel pump part way open.. so when you stop running the engine or stop cranking the engine..

the fuel runs all the way back to the tank...  leaving you with only a part fuel bowl full of gasoline.. the engine starts and runs on the partial bowl for a few seconds then dies..  you have to crank the engine for one to two minutes to get it to restart...

does that sound familiar.???

on a cold engine.. disconnect the fuel line at the carb inlet.. extend the fuel line with a piece of fuel hose..  BLOW INTO IT.. i bet you can make bubbles in the fuel tank..  please don't try this in your garage... with that end of the car near the water heater..  you can blow fuel right out the filler neck if the tank is over half full.

i have taken to changing the fuel hose between the line coming out of the frame and the fuel pump inlet.. i create a LOOP in this hose.. i then.. cut into it and install a fuel filter.. usually something from a 90s ford product.. there are several styles.. some have a 5/16 tube size.. and others like early 2000 versions have a 10MM tube size.. either size you can push fuel hose over and clamp it.. these have a very fine filter element.. like 7 or 10 micron..  and enough area it takes a while to clog..

please also if you have your sending unit out.. drop some magnets into the fuel tank.. they will attract the sediment and keep it out of the fuel system..


if you disable the ignition system..  so no sparks can be created..  have somebody crank the engine with the fuel line extended into a clean.. clear plastic 2 or 3 liter soda bottle.. while you observe the pulses..  do you get a nice full pulse each time..  you should have over a pint of fuel after 15 timed seconds...

if it takes a while before the pulses start.. you have found your issue..

install the filter before the pump.. crank the engine another 3 or 4 fifteen second trials... pour gas back in tank..  the full flow of the clean fuel will usually clean the check valves in the fuel pump..  

you can also if you have clear hose.. hang that over the hood latch.. and hook it to the fuel line.  crank the engine till fuel is visible.. stop cranking.. and watch it vanish back into the line thru 2 check valves..

i have gone thru this on TOO MANY CARS...  its cheep... just a fuel filter and 2 feet of hose and 4 clamps..  under 20 bucks..  


and CLEAR FUEL FILTERS will not work.. sorry.. they don't have fine enough media to catch the debris... which is really fine RUST..

this is an FF744 with 10MM inlet and outlets that you might be able to shove greased 3/8 fuel hose over the ridges..

FF744 10Mm15bucks  

gcpontiac73 gcpontiac73
New User | Posts: 3 | Joined: 08/10
Posted: 01/13/14
12:29 AM

Wayne is the one who diagnosed my car the last time. He said...if its too close for missiles better check the points.

Now he's saying sediment in fuel tank. Sounds like a good place to look. Car has sat awhile.

I'll give you an update thanks again.  

shyrgfuh3 shyrgfuh3
Enthusiast | Posts: 447 | Joined: 11/13
Posted: 01/13/14
01:47 AM

You have not answered my question regarding your carb type/brand.  

gastiresoil gastiresoil
New User | Posts: 29 | Joined: 01/14
Posted: 01/21/14
08:23 PM

I'd start troubleshooting by squirting a little gas in the carb to attempt to keep it running, if it stays running, its a fuel issue, if not, its an electrical issue.

I have had this issue in the past, if fuel, I have found a hose gone bad internal sucking the line closed, change the hose.
If electrical, feel the coil, if its hot, good chance its shorted and will run shortly till the spark jumps internally, try a knone good coil just hook it up and lay it on the intake. Other possibility is the same issue with the condenser, its made the same way as the coil.

Good luck

GTO guy  

gastiresoil gastiresoil
New User | Posts: 29 | Joined: 01/14
Posted: 01/21/14
08:24 PM

I'd start troubleshooting by squirting a little gas in the carb to attempt to keep it running, if it stays running, its a fuel issue, if not, its an electrical issue.

I have had this issue in the past, if fuel, I have found a hose gone bad internal sucking the line closed, change the hose.
If electrical, feel the coil, if its hot, good chance its shorted and will run shortly till the spark jumps internally, try a knone good coil just hook it up and lay it on the intake. Other possibility is the same issue with the condenser, its made the same way as the coil.

Good luck

GTO guy  

gastiresoil gastiresoil
New User | Posts: 29 | Joined: 01/14
Posted: 01/21/14
08:24 PM

I'd start troubleshooting by squirting a little gas in the carb to attempt to keep it running, if it stays running, its a fuel issue, if not, its an electrical issue.

I have had this issue in the past, if fuel, I have found a hose gone bad internal sucking the line closed, change the hose.
If electrical, feel the coil, if its hot, good chance its shorted and will run shortly till the spark jumps internally, try a knone good coil just hook it up and lay it on the intake. Other possibility is the same issue with the condenser, its made the same way as the coil.

Good luck

GTO guy