Fuel delivery issue on Twin 45 DCOE's

[sleeky]

Hi ive recently added a pair of 45dcoe's onto my 2T-G got it tuned and it went fine.. but whenever i go up or down a hill it stalls almost instantly.. on straight road its fine so i know that my fuel pump isnt strong enough to push enough fuel for them to keep the car idling or going... so my question is, what other options for fuel pumps are there ? i currently have an electric pierburg pump.

cheers.

[Crazyracer]

If its happening going up or down hills its probably a float level issue and not the pump. Check that the float levels are set correctly and that the floats don't have any holes or splits. If the Webers have the brass floats, any holes can probably be soldered up, but if they're plastic and split they will most likely need replacing.

If you're worried about the fuel pump get either a Facet or Holley pump. Some of them can pump too much pressure however and overcome the needle valve, so you may also need a fuel pressure regulator (one designed for carbies, not an EFI one). There are some with adjustable pressure around.

Also worth checking that your fuel filter and the gauzes in the fuel entry port to the webers aren't clogged with crap. If water has got into the filter it can reduce the flow of fuel and you won't be able to see it.

I may have a fuel pump and a regulator to spare. PM me if you're interested.

[Andrew162]

also fwiw, check vacuum lines and EGR if it's enabled. I had a similar problem on a car I once owned with twin 42mm DCOE Web's as well, and the EGR had been disabled, resembling similar symptoms to what you're describing here. also I had water in the system once and that was causing all manner of headaches.

[Rodger]

sleeky,

I suggest more driving tests. You say it runs ok on the flat road. Is this just cruising at say 100km?

You say it dies, looses power going up a hill. Do you need to push harder than normal on the accelerator to maintian speed, ie to WOT or does it just get worse as you open them up a bit more?

Going down hill, maintaining a speed uses only a little throttle so those symptoms should not be present.

If the engine drops to idle, say if you disengage the clutch whilst going down hill, does it then stall (a symptom of poor idle speed/mixture)?

I suggest take it out on a long flat road or to the track or onto the dyno. If the fuel pump is not supplying enough flow it will quickly show up at WOT on a long run, as a power role off and then turn to missing an dpinging as it goes way lean.

A split float will cause that carby to flood and that shows up different symptoms.

At cruise the Pilot jetting may be correct but the main jetting may be lean so as you move more onto the main system it starts to run lean and rough.

Anything stopping good fuel flow will drop power off at high load and throttle openings.

More testing and info please.

Regards

Rodger

[sleeky]

Basiclly.. it doesnt matter if i cruise at 60 or 100 foot to the floor or only just touching it, it goes perfectly fine. However, if im cruising at 60 or any speed at all and go up a hill or down a hill, within a few seconds it will stall. i pulled out the top hose that first enters the front carburettor and when i turn my fuel pump on it basiclly trickles out.. im getting full voltage on my pump aswell which is weird and im sure nothing is cloging it, ive seen it flow out alot better.. ???

[joecoolmk2]

if it dies instantly, then either the pump doesn't supply enough fuel, or the floats are set way low.

with the fuel pump though, for it to stall instantaneously, the fuel bowls can't be full, i.e. your pump is only just keeping up when you're driving on flat roads, and when you go up a hill the motor starves of fuel.

i'd get a better (higher volume) pump, and if it still does it then you'll have to pull the carbies apart.

[sleeky]

if it dies instantly, then either the pump doesn't supply enough fuel, or the floats are set way low.

with the fuel pump though, for it to stall instantaneously, the fuel bowls can't be full, i.e. your pump is only just keeping up when you're driving on flat roads, and when you go up a hill the motor starves of fuel.

i'd get a better (higher volume) pump, and if it still does it then you'll have to pull the carbies apart.

thats what i said before, because i got the car dyno tuned (100HP atw) and it was fine.. but yeah im thinking my fuel pump isnt strong enough and or/ the floats are set too low.. what other pumps are out there thats sutied for my setup?

[joecoolmk2]

what have you got now anyway???

there's FEDTRO high volume low pressure pumps on ebay for $59. I had one of these on my 18RG and it was good. here's a link: http://cgi.ebay.com.au/ELECTRIC-FUEL...QQcmdZViewItem

[sleeky]

what have you got now anyway???

there's FEDTRO high volume low pressure pumps on ebay for $59. I had one of these on my 18RG and it was good. here's a link: http://cgi.ebay.com.au/ELECTRIC-FUEL...QQcmdZViewItem

i run a low pressure Pierburg pump.. thanks ill look that up.

cheers.

[The Real Roadrunner]

if you just got it dynoed it should have shown a pump problem then.
have you checked the pickup in the tank or wether there is something in the filter or lines before the pump.

[Dazza]

If your fuel pump was weak you wouldn't be able to use more than about quarter throttle even on flat ground.I would say that your float level is set too high so that fuel runs into the air corrector jets on uneven ground.

[Andrew162]

Basiclly.. it doesnt matter if i cruise at 60 or 100 foot to the floor or only just touching it, it goes perfectly fine. However, if im cruising at 60 or any speed at all and go up a hill or down a hill, within a few seconds it will stall. i pulled out the top hose that first enters the front carburettor and when i turn my fuel pump on it basiclly trickles out.. im getting full voltage on my pump aswell which is weird and im sure nothing is cloging it, ive seen it flow out alot better.. ???

ok first thing I think of is filter, or fuel lines as roadrunner said too... are either of those easily accessible to inspect?

[Dazza]

It could be that the check valves in the pump don't seat properly when at certain angles. Try mounting your pump at 90 degrees from how it is now, so what is now the front faces one side.

[sleeky]

If i plant it, itl go, but it doesnt go anywhere near as hard as the 40mm solexs i had on there before, could it be to do with the tune/diff main jets etc? The pump has always worked well on my 40mm it only has been doing this when i got the 45s put on.

As for fuel lines and anything being clogged up ive taken the pump off and inspected it for anything and nothing has come up, ive also taken my tank out and cleaned that out.


What do you think of this??

http://cgi.ebay.com.au/Electric-Fuel...QQcmdZViewItem

cheers.

[Talasas]

If it is the pump and you want to try, you can get an electric fuel pump from a Subaru EA82 engine, they are small, light and designed for carbies. They are cheap and work really well.