She won't stay running! Any Ideas?

[mr.bridger]

Finally got Ursula running,she idles quite nicely,very responsive when given throttle,once I drive her around the block a few times(10 minutes or so) She acts like she's starved of fuel,runs rough,then splutters out. Then I have to wait about 2 hours to get her to start again,she acts like nothing happened,until she does it again! I have rebuilt the fuel pump,it seems to be fine.Cleaned out the lines again from carbs to tanks. Rebuilt the carbs earlier,they seem to function in unison.Some friends have suggested it may be vapor lock,not sure what to do at this point...any suggestions for this S5?

 

[alpine_64]

It does sound like a heat related issue with the carbs.. are they the Stromberg 150's? After it stops and you try restarting, what does it do?

Is there a strong fuel smell, is it possible the choke is not shutting off completely.. might explain nice idle at start and then while cold.. then when hot floods the carbs?

the other option might be something electrical,

 

[tony perrett]

Check that the tank vent is clear. When the car stalls, open the fuel cap and listen for the hiss of air entering the tanks.

 

[junkman]

When it dies check for spark the coil may be dying, classic bad coil symptoms.
Jeff

 

[Chuck Ingram]

By any chance did you forget to change the fuel filter?

 

[anduril3019]

Sounds like fuel tanks

You said you cleaned the lines, but have you checked the inside of the tanks and crossover tube between tanks (assuming you don't have a SI or II). Even if the line isn't clogged, the large paint flakes in mine used to float and settle over the outlet to the fuel line and block it intermittently, it would even flow fine when I disconnected the line to check, and the line would be clean from tank to carbs. The driving symptoms sound almost exactly like what I experienced.

 

[mferris]

After my last experience - I'd always start with the lines/tanks.

After it dies - disconnect the fuel line (on the tanks side of the pump) and see if you have any volume of gravity feed when held lower than the tanks.

Mine had similar symptoms - and I disconnected the line but only a few drips, blew it backward into the tanks with an air hose (carefully) - then a strong stream would flow - until the output of the tanks was blocked again by the flakes from the inside of the tanks.

I was dumbfounded by the fact that my carb was flooding the intake manifold - which made me think it was an oversupply of fuel. My presumption is that the the line was getting clogged at the tanks, and the fuel pump would pull a vacuum, then once enough pressure was built up to clear the blockage - blow past the valve in the carb (32/36) and flood the engine. (or at least I think).

Removed the tanks, and cleaned/recoated and everything worked great.

Your mileage may greatly vary.

 

[RootesRooter]

You mentioned the fuel pump is fine, but have you checked for black paint flecks in the recesses?

I suggest shooting a little starting fluid into it after it dies. That should resolve whether its fuel or electrical.

 

[mr.bridger]

Thanks to all! I will start fooling with it this weekend,hope I can finally go for a nice long drive,my neighbors are sick of me going around in circles! I will let you know how things progress...