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Fuel pump - electric or mechanical

Posted: 05 Jun 2016, 13:47
by ads288
Hi all

My van has had some work done and is finally starting again :)

I've taken it for a few runs to the local shops and back and everything seemed hunky dory. Famous last words.

But.....when I took it for a longer drive and hit over 30mph Im having issues. It stutters and loses power. It will start pretty much straight away. But symptoms return fairly quickly. It's also running much hotter than usual. No popping sounds or backfires.

I'm thinking fuel starvation. Tank is fine and I've got new fuel lines and filters. Carb has been throughly cleaned and had a service kit with all the new bits.

As such the only fuel part left is the pump. It's got an electric one at the moment.

Just wanted some advice to replace with either an electric or back to mechanical?

It's a 1.9dg with a Weber carb.

Mocki mentioned a cheap electric one on eBay in a previous thread:

https://club8090.co.uk/forum/viewtopic.php?t=149081" onclick="window.open(this.href);return false;

I like the price! And for that amount of money it may be worth a try

Re: Fuel pump - electric or mechanical

Posted: 05 Jun 2016, 14:48
by bigherb
That pump is too high a pressure especially for a Webber.
This is the correct one.
http://www.ebay.co.uk/itm/Facet-Posi-Fl ... SwAL9UeXYH" onclick="window.open(this.href);return false;
But before you go replacing parts check the fuel flow rate from the fitted pump.
Usually the pump manufacturer state a litres per hour just, time how long the pump takes to fill a measured container.

Re: Fuel pump - electric or mechanical

Posted: 05 Jun 2016, 15:40
by ads288
That's for the reply big herb

I think the existing electrical pump is very generic so maybe unable to find any manufacturer specifications.

Previously it had filled up a small cup fairly rapidly. But that's not a very scientific way of doing things. I will see how long it takes to fill a 5l petrol can.



Sent from my Redmi Note 3 using Tapatalk

Re: Fuel pump - electric or mechanical

Posted: 05 Jun 2016, 16:00
by bigherb
Sorry I linked to the wrong pump edited it now.

Re: Fuel pump - electric or mechanical

Posted: 05 Jun 2016, 18:24
by ads288
thanks for the help - much appreaciated.

Think Im going to buy one - just a couple of more questions :)

NPT fittings - the pump linked doesn't come with any - so I guess I need 2x male 1/8 NPT with a 8mm diameter? ( i think thats what my fuel lines are)

Currently the pump is located near the carb - the ebay listing says it should not be mounted above the tank. Should I put the new pump where it currently lives or somewhere else?

Image

Re: Fuel pump - electric or mechanical

Posted: 05 Jun 2016, 19:27
by CovKid
As close to tank as possible. My guess it was mounted there as it was the easiest solution at the time but its not the right place for an electric pump. They can 'push' but are hopeless at 'pulling' fuel that distance.

Re: Fuel pump - electric or mechanical

Posted: 05 Jun 2016, 19:28
by ads288
thanks CovKid

Re: Fuel pump - electric or mechanical

Posted: 06 Jun 2016, 15:49
by bigherb
ads288 wrote: NPT fittings - the pump linked doesn't come with any - so I guess I need 2x male 1/8 NPT with a 8mm diameter? ( i think thats what my fuel lines are)
You need 8mm for the inlet check your outlet it could be 6mm
Mount the pump something like this, note the pump outlet should be angled higher than the inlet to stop trapped air.
Image

Re: Fuel pump - electric or mechanical

Posted: 06 Jun 2016, 21:14
by garyd
Given that the pump appears to mounted in the 'wrong' place, it might be worth re-locating the old one before spending money on a new one.

The work involved won't be wasted since any new one needs to be by the tank anyway.

Re: Fuel pump - electric or mechanical

Posted: 06 Jun 2016, 21:31
by Mr Bean
When I eventually moved into the world of fuel injection I had to abandon my (some might say quaint) preference for mechanical fuel pumps. This is based on the fact that with a mechanical pump stops when the engine stops while the ignition remains on. Like probably in most crashes unless the vehicle has an inertial fuel cut out.
Apart from this fad there are a few arguable pros and cons:

Engine compartment:
Pro's - accessibility, shorter pressurized pipe run, ability to suck or blow down pipe to check for or clear suspected blockages.
Con's - proneness to starvation due negative fuel head (Less pressure difference) and evaporation/cavitation due to engine heat.

Down near tank:
Pro's - pump primed at all times, fuel pushed rather than sucked up to carburetor, bulk of fuel line run at pressure.
Con's - poor accessibility, not possible to check or clear blockages by blowing down fuel line, more joints to leak.

IMO and unless anyone has any more contributions down by the tank is better.
CS

Re: Fuel pump - electric or mechanical

Posted: 07 Jun 2016, 14:42
by ads288
Thanks for the replies everyone - very useful info.

I've ordered a new pump - as for £27 is a fairly cheap part and worth it for piece of mind. I'll keep the other as a spare.

I think moving it is the best option - The Van currently has an immobiliser (which I have no idea how it works) which turns on /off the fuel pump.

Re: Fuel pump - electric or mechanical

Posted: 30 Jun 2016, 07:53
by ads288
The garage have fitted the pump near the tank - but Its still having problems.

It will start then die so the garage thinks the pump isn't strong enough. They recommend trying to get hold of one with a bigger flow rate.

The older pump I have seems to work a little better.

Just wondered if anyone else had any ideas?

Re: Fuel pump - electric or mechanical

Posted: 01 Jul 2016, 07:57
by ads288
Does anyone think this page makes any sense?

http://www.racetep.com/manufacturer/web ... pumps.html" onclick="window.open(this.href);return false;