Help Please

[Steve Clarke]

I have driven my 1934 Ford street rod for some 5,00kms including to the Australian Street Rod Nationals in Queensland. Draged it, Skid pan and circuit raced with out a hick-up.
During the last 2 days of the journey it began to fault.
While crusing along, say 1000 rpm, the engine quits (as if the key had been turned off) slip it into neutral and it restarts.
This happened about 10 times in the one day!
That evening we travelled to Tasmania on the overnight ferry and I turned the battery off.
Next day travelled 2 hours and it stopped again, this time it would not restart
I checked the fuel filter and pump all OK
Went to the first of the 2 fuel lines at the engine (the return line) opened the banjo fiting, wound it over and a large amount of air blew out followed by fuel.
Engine restarted
30 kms later same routine
40 kms later could not get it to restart
towed the last 5 kms home
next day would not start but did not check spark or injector firing but fitted a fuel pressure guage
next day started
next day drove it 30 kms and left it idling for several minutes and it stopped dead, restarted immediatly (it also has a higher idle that normal )
any ideas ????
my rod uses a standard crown computer and cut down wiring loom so im guessing that the code test pin will be inoperative although i've never checked it

 

[Peewee]

So you've diagnosed that you are getting air in the fuel lines?

Have you got a proper efi tank? or maybe a surge tank?
Is all that working? no leaks?

Electrically look at the crank angle sensor, make sure that it plugged in and tight.

 

[chrisman]

it could be a ton of things,, but since it sounds like a new project, im wondering if it something simple..

first of all,, it does sound like a fuel prob to me..a couple of basics first.. does the fuel tank have an adequate vent? you could be creating a vacum in the tank which puts a strain on the pump which may starve fuel..
is the engine getting hot? we used to have problems with vapor lock-before efi- and the symptoms sound familiar...
it could be an electrical prob also,, but you will need to check for codes somehow.. anyway, il keep an eye on the thread..

 

[Peewee]

How was the fuel pressure on the guage?

 

[Steve Clarke]

Thanks Peewee and Chrisman,
Problem solved (I hope)
When I restarted the car with the battery disconnected for 3 weeks (away with work) It played-up immediately
stopped about 10 times in 15 minutes
I was running my hand around the wiring loom looking for kinks and breaks and found that the "circut open" main relay was warmer than the others
exchanged it and it ran for an hour or so last night (until It ran out of fuel) and never missed a beat so I hope that is it
To answer the questions,
I built the aluminium tank which has 4 compartments with the return entering the centre compartment where the outlet is (sort of surge tank
The tank is fitted with a late model Unleaded cap and kneck and is vented
The car ran for 5000kms before the trouble started so I am reluctant to think its a design fault, although I still cant understand why I was getting air out of the fuel rail
Is the vaccum controlled valve in the return line a pressure regulator??
The fuel pressure is 280 KPA
thanks again all
I'll post the result after the weekend

 

[Peewee]

I'd say the VSV on the charcoal canister line would just switch off under certain conditions, like full throttle. But that is just a guess.
Factory fuel pressure should be 290kPa, but this is at full throttle, not idle.
Unplug the vacuum line on the FPR and see if it goes up to 290kPa.
If it doesn't, perhaps the fuel pump is too small? I doubt that though.

Air in the lines is a strange thing indeed.
Only place it can come from is the tank. Unless the FPR or dampener is leaking?

 

[Zuffen]

Have you explored the possibility of an air leak before the fuel pump.

It may not be big enough to leak fuel but once the pump starts to suck the air will bleed into the line by the venturi effect.

May bbe a little out of left field but worth a look.