dirty holley

[Anonymous]

hey guys,

i have a 600 vac sec holley on my new XC, yesterday i ran the fuel very low..... a cough and splutter into the petrol station to be exact..... after i filled up i had big troubles starting the car..... just didnt seem to want the petrol.... now i assume its probably picked up all the sh!t from the bottom of the tank, now will some carby cleaner fix this right up? or is it going to require me cleaning something more in the carb?????

cheers in advance

-matt-

 

[addo]

Electric pump or mechanical?

 

[Anonymous]

mechanical.... the filter just before the carby is completly empty.... i assume thats needs to be full otherwise it cant supply enough fuel.... i might blow back through the lines and see if its a little blocked... then hopefully the filter should fill...........

 

[xctasy]

First, check for dirt. Hope you don't have a full 125 litre long range tank, cause the first thing to do I'd do is drop it, and clean it. Holleys need clean fuel, and it if ain't clean, then you'll need to get a new stock Holley float bowl filter, remote filter as insurance, and you'll still maybee have issues.

Second, I recon what your suffering from is a hot fuel handling problem, but it is caused by dirt from excessive pump pressure. Holleys hate dirt.

Here's what you can do once you've checked the dirt issue.

All American fuel system are built with high pressure. Holleys run too much fuel pressure for modern fuels. 7 psi of stock pressure from the Carter fuel pump can be enough to stir up any dirt and crap in the tank or fuel bowl. The float levels are very dependant on there being lots of pressure on the needle and seat valve. Hot fuel soak is also common, and the fuel these days has a lower vapourises pressure than in the good old days of lead fuel. Our modern fuels are much worse than the old leaded RON 97 in this repspect. It's a factor in most Carter Thermoquad carbed Fords as well, and there are solutions:-

Option One is the best and cheepest. Spend a few hundred ping and get a pressure regulator valve and place it on one of the intake studs very close the the carb. Run a short length of the stock size line to the carb, and reduce the pressure to 2.5 to 3.5 psi max.

Ford never used Holleys in any of its unleaded emission era stuff unless it had some kind of bleed-off device, because of this issue. In 1969 when there was 105 ocatane gas at the pumps, fuel starts and hot-fuel soak wasn't an issue.

Option Two is to look for a carb with a return line, such as the US spec 4180 5.0 HO 600 cfm carb used on Mustangs from October 1983. Run the XE Falcon Carter fuel pump topper or the Mustang 5.0 mechanical fuel pump.

Ford did this in Oz with the Weber ADM 34 carb in the cross-flows with huge sucess. In the US, they did it with all 4-bbl V8 5.0 Mustangs, and 460 F150/250'as well.

You'll notice another thing with either one of these items. The fuel consumption will drop as the needle and seat is less affected by bumps, and your fuel problems should be a thing of the past.

 

[Anonymous]

thanks xecute,
ill look into it.... i sorted out the main problem i just recently had.... all i had to do was actually move outside and look under the bonnet.... i was just putting it off due to my hangover hahah but yeh anyway... the fuel filter had been put on the wrong way around! i guess its been like that for a fair while.... so the filter bowl was unable to fill, so i assume it just couldnt get enough fuel in to run properly.... it still does have some minor fuel issues... but i like the idea of sorting out the fuel pressure prob before it becomes a big pain!

cheers!

-matt-