Do I need 2 sets of wiring with relays or can I use one and bridge the pumps??

 

Yes mate to need to separate feeds from the battery or you risk not having enough voltage when your are going flat out.
Just make or buy two looms for each pump and use the same trigger for both.

Rich

 

Mine has a second relay both relays have there own earth and live feed then each relay feeds one pump. The ecu trigger wire go's to one relay then loops from that one too the other

 

My ATL Cell runs 2 internal 044's and wiring splits to run the both pumps inside the tank from standard
and powered from a single relay and I've never had any probs , I would say you'll be fine with one aftermarket loom running both as the problem was always voltage drop with old standard wiring , however I would split the wiring to both pumps and not bridge one to the other if you know what I mean

 

Running two consumers off one feed is never a good idea really

 

Yeah thought that was the case...


Thanks for the replies fellas

 

i can make twin pump looms up in needed

 

It's more the danger side I should think, i.e. the cable will not be rated for the draw to supply both of them.

So at best you would blow the fuse.

Martin

 

Hi James how much would 1 of these cost?

 

If you drop me an email james@evolutionchips.com I will have a look for you mate.

 

Would you not be tempted to run them in series? That way if one pump failed/went open circuit both would stop working, rather than one failing which could mean running lean?

http://www.bosch.com.au/car_parts/en.../fuelpumps.pdf

The 044 has a max continuous current rating of 15.5A so imagine a max continuous rating of 31A. 4mm2 tri rated cable would be fine for this with a resistance of circa 10m Ohms would mean a voltage drop of 0.31V. I suspect the pumps would on average draw less than 12A each.

The other option would be to use a circuit which monitored pump current and disabled both pumps together if one failed..?

 

First sensible suggestion. I was going to suggest that but you get experts who think they know everything posting & its not worth the aggro.


Always use a single pump is the best solution. A control circuit you suggest is built into my new pumps so I can go to 2 pumps for the first time safely.

 

lol your right Rod, I was expecting some comments! I went off and had a quick google and it looks like a few high powered Supras have failed due to one pump failing not both.

Rob,

 

The question wasn't about fuel systems, if it was I would always where possible advise the use of one pump, but even that has its risks
The OP asked if he could bridge one pump to the next, which given most fuel pump looms are 20-25 amp cable over the length of the run I would suggest not.
Also I've still never seen an 044 go open circuit,not saying it doesn't or cant happen, but it would be very rare. They just start to loose flow and wiring in series would not help in this case.
I can make the Looms up to any spec required, so if the OP wants to research options im sure we can help

 

Hi James,

Was really just thinking out loud. The question is, do 044 pumps loose flow because of mechanical wear of because of something else? In either case monitoring of current would tell you a lot about the pumps current state, more so actually than measuring the voltage at the pump. This is all probably pointless for the OP but interesting all the same.

As an example, I monitor ignition coil current, that tells me absolutely every thing I need to know about the coil. Short, open, coil saturation point for ideal dwell times etc. Its really very useful.

All the best, and I'm sure either way the loom will be of great quality.

Rob,

 

The only way to effectively monitor if the fuel supply is OK is on rail pressure and AFR, and even then you could have an injector fail... so AFR or EGT on each cylinder...
And i'll bet most dont have an ECU capable of monitoring so many inputs and good enough error strategies to do anything effective about it if a fault does occur.

 

Rob my comment really wasn't aimed at you mate, it was aimed at the "older" generation who like to put everyone else down and prevent good tech discussions ever taking place.




It is certainly an interesting subject and topic, fuel systems are very hard to get 100% fail safe, anything that can help towards this is only a plus really,


ive never taken an 044 pump apart, but when they have issues its normally a flow issue under high fuel demand and the rail pressure drops at high rpm, nasty really as you have no idea your about to have a melt down because the pump is still flowing plenty to run fine low down. Its only when you ask them to raise pressure they fail.
This is similar to if one pump fails on a twin pump system and you are relying on the supply from 2 pumps to meet demand,


Its also fine having gauges and dials everywhere monitoring all this but when your "on it" in the car you just don't have time to look at them all and take in all the information, so it really does have to be controlled by the ecu or something that can take action for you.
And then the issue of what action you take, cutting fuel all together in something like a track car on a busy track circuit could be pretty dangerous, getting rear ended at high speed wouldn't be much fun,
I would be trying to get a low fuel pressure warning or pump failure to cut boost so you still have the ability to move under your own steam to get out of the way of others. That's something people who drive in a straight line on their own don't think about.

 

Good stuff and thanks for the clarity James. Sorry to blab over the OP's thread its just a subject I have never given much thought to.

All the best

 

Thats sort of true, the trouble is that AFR and fuel pressure are post events, reactive. So the pump can fail/go weak and you can have a slight delay before you see an AFR or pressure change. By then the change happens very quickly and you have little or no time to reduce boost etcetc. Being able to see a pump fail or begin to fail as it happens with no delay would be a faster way to avoid terminal failure.

That being said, ultimately AFR, EGT and fuel pressure would still give you very useful info, having just one of those gauges in your car is more than most people have any way.... It always makes me laugh when you see a million gauges in a car, clock, volts, water temp, maybe an oil pressure gauge but rarely something as instantly useful as EGT or AFR..... Plus an AFR gauge has loads of flashing lights so you would think Kevin would love it?


Rob,

 

Mines on two pumps an 044 that's fed from the tank that feeds my swirl pot over kill I know but I had two of them. Then a second 044 that's fed from the swirl pot and feeds the fuel rail. That pump will be changed for a better pump with my 650 engine. Each pump has its own live feed via its own relay. My afr gauge may not be anywhere near as good as workshop equipment but will give me a quick indication if there's a fuel problem.

 

interesting topic.

 

Thanks for all the replies, something to thing about...


I have a 023 feeding the fuel swirl then 2 x 044's to the rail.


Just a thought but would both 044's need to be running all the time or could one be switch on when needed??