Fuel pump problem?

[Mr Bling]

Has anyone had a similar problem to this.....
engine starts ok, idles ok and pulls away fine. After a mile or so and usually when in fifth gear, the engine starts to hesitate then cuts out completely. Fuel pressure gauge at this point reads zero so I know it is fuel starvation. Checked all wiring connections and circuit is working, earths etc all ok. Pump seems to stop intermitently. having said this she has just driven 15 miles and the problem did not rear its head. Not consistent so I don't know what to try next. The pump is a Holley Red Top, only 18 months old and done 2800 miles. Mounted below level of fuel tank next to gearbox. Was working fine before winter set in. Don't really want to replace it until i am sure where the problem is. All suggestions gratefully received.
Cheers
James

[mylesdw]

Well I guess if the pump stops occasionally it is more likely to be a wiring problem. What did you need to do to get it going again?

Is your pump wired through any sort of safety cut-out, inertia switch, oil pressure switch? Does it coincide with something else, maybe the fans coming on?

I have run Holley red tops for a good many years and have not come across any reliability problems with them.

[Mr Bling]

Thanx Myles
I have a cut out switch but tested this and seems ok. Does not seem to be related to any conflicting circuits.
J

[wilf]

Is your fuel pump wired through an oil pressure switch? Sometimes done to stop the fuel pump from running after an accident. Not a bad idea, really.

Might be something else to check.

Can you temporarily fit a light from the "hot" (+ve) side of the fuel pump and earth, visible in the cockpit? If the light goes out, power has been lost to the pump, therefore wiring/relay fault.

If the light stays on, yet the pump stops, earth or pump fault.

Edit - oops, just saw that Myles had covered the oil pressure switch thing already.

[mylesdw]

Can't think what else to suggest. The Holley is a very simple beast; the two wires on the top of the pump simply join by two short links to the motor brushes. There's nothing much to go wrong, especially intermittently. It is quite simple to take it apart but a little tricky to get back together (you need some little ty-wraps to hold the brushes in during assembly).

Are you sure it is actually stopping? another thought is that the built in pressure relief valve is sticking occasionally.

[neil still building it]

hi this pump couldn't be running hot/overheating ....
or is there any restriction on the inlet side or fuel pipe collapsing.....
ie do you have a good thick wall rubber pipe,or lack of air getting in the tank....just a few reasons perhaps ...
i had a 'problem in saudi with my 'vette....finally traced to a trapped fuel line (pinched between a tank securing strap and tank body...!) it took perhaps 2 weeks of messing about and it wasn't till i dropped the tank (all with not many tools!) that i stumbled across the real problem! DOH!!! after checking for air leaks, fuel blockages, restrictions etc ....
hope it 's simple to find...!
all the best
NEIL

[Purple AK]

James.
I had exactly the same sort of thing. It turned out to be dust/crap that had accumulated in the tank during the build period blocking the filter in the pump and causing low pressure. I cleaned it out and fitted a new filter between the tank and the pump and it's been ok ever since. As a test, remove the outlet hose from the pump and run a hose from the pump into a jerry can. It should pump about 70 gals per hour. Mine was a trickle

[Mr Bling]

thanx guys - some really good pointers there. Will check all at at w/e

cheers
J