Cam driven or electric fuel pump ?

J

James

Member
Fellow Frogger
Joined
Aug 28, 2000
Messages
232
Location
St Mary's Pennsylvania
Heading back to NZ for a month's holiday from Canada. Before I can drive my 405 (XU9J2 engine) I need to fix the damn fuel pump. Since putting the 45 DCOE Webers on I have had to make some adjustments. As the Webers like about 3psi I have a Holley fuel pressure regulator feeding them via the cam driven fuel pump. This is leaking and I think I have a fuel supply problem at the top end.
Is it as easy as removing the pump and blanking the hole off. Then installing the electric pump ? question

<small>[ 09 May 2002, 09:09 AM: Message edited by: James ]</small>
 
Hey man,
a bit off topic as I cant help with your fuel pump, but where in NZ you coming back to?? Christchurch right?? If so I'd be keen to meet up and have a look at this tricked up 405 Mi16 (is that right?) of yours.
Hope you get your fuel pump sorted.

Izza
 
Hey James, I had a 160hp 2110cc VW motor running twin Dellorto 45s, the standard cam driven fuel pump didn't have a prob with supply.

I might suggest if it's not supplying enough fuel, maybe looking for worn parts in it maybe a cheaper option... ie the rod that the lobe pushes up and down might have worn down over time?
 
Most aftermarket electric fuel pumps like to "push" rather than "suck". ie they need a head of fuel to prime them. Why not use a std. FI pump in the tank, then use a regulator to drop down to 3-4 psi?
 
We were having a fuel surge problem on the CX GTi when we got it at first due to pump location etc. My son fitted an electric pump (capacitator type) at the rear of the car and used it to blow fuel through to a "surge tank" or swirl pot under the bonet which in turn fed the fuel to the FI pump. After stuffing around making swirl pots etc, it was found that a filter off an EFi Commodore V6 was a good size & efficiently did the job.
This is a variation on PeterT's idea, only this way you end up paying $30 for a big filter and $60 - $70 for a pump, instead of $300 + for the pump plus whatever else you might need.
These pumps work at around 5 psi from memory and simply cut out as the pressure is reached. May even be good enough to handle the job without resorting to swirl pots anf cam driven pumps.
Fairly simple job tp wire into the ignition circuit.

Alan S
 
I think that if the mechanical pump is capable of enough flow, then stick with it. You can be always sure that a mechnical pump stops when the engine stops (i.e. in a crash). With electrical pumps, even with inertia switches, you still have the possibility of a relay shorting closed, etc. I'm not saying that electrical pumps are dangerous, just that mechanical pumps are a bit simpler and generally more fail-safe. Mechanical pumps are also dirt cheap to replace compared with electric pumps (e.g they're usually under half the price).

Dave
 
If you do decide to go down the mechanical route, one trick my brother and I did on an old worn VW pump was to weld a tiny bit more length onto the rod driven by the lobe - worked a treat! :)

I have no idea whether the 405 has the pump driven in this way though?
 
Thanks for the replies guys, I will tinker today and see if I have any luck. From what I can see the cam driven pump just needs a new gaskit. Have taken some shots on the digital cam so will have em posted under my car on the Pic site soon.
I returned to Auckland not Chch sorry.
Im one of those 'Ponsonby Wankers' with a Peugeot in the drive.

Later.......... :cool:
 
You must log in or register to reply here.
Top