Hüco Fuel Pump Set Up??

[donaldb7]

Hi all,

So I've ordered myself a Hüco fuel pump from FRC as well as an eBay inertia switch for safety and a three pin connector. I am a total novice when it comes to electrical systems so I will need this explained to me in layman's terms!

I've been going through the previous topics, reading about other people's experiences with the installation. From what I can tell, I don't have a ballast resistor. I'll be replacing the old mechanical pump with this new electric pump, and mounting it somewhere on the inner right wing I reckon. So, some questions...

- What wire gauge should I be using for this? And does colour matter?
- Will I need a fuse if I'm going to be using an inertia switch? If yes, should the fuse be in the fuse box?
- Will I need a relay?
- Is it important to use an inline filter before the pump? I already have one after the pump, before the carb
- Where should I take the 12V power from?
- What electrical connections are best to use? Spade connectors?


I'm sure I'll continue thinking of questions, but this is starting to fry my brain already....

Many thanks for any help in advance. Any advice is welcome!

Donald

[mangocrazy]

I'm currently using a Huco pump and find it works well. I have a relay, fused connection and inertia switch ready to fit but Covid has meant I've had little chance to get to the car (it's in the south of France). I'm like you as regards electrical things, in that I need a diagram to work from and clear instructions...   Here is my take on your questions; I'm sure others will be along to correct and/or flesh out my replies..

- What wire gauge should I be using for this? And does colour matter?

The Huco pump comes with two 'tails', a positive (red) and negative (black). Wire gauge is quite light, so current draw is not excessive. I'd stick with the same colours to avoid confusion. Vehicle Wiring Products are an excellent source of wiring consumables including cable (https://www.vehiclewiringproducts.co.uk/). I'd definitely use thin wall cable, and you'd probably get away with 1mm/16.5 amp cable, but I'd probably use 2mm/25 amp to be on the safe side. You may need heavier gauge cable to connect to battery and/or relay, but others can advise on this.

- Will I need a fuse if I'm going to be using an inertia switch? If yes, should the fuse be in the fuse box?

You will need a fuse, but I believe an inline fuse on the lead to the battery will be fine. Again, I am happy to stand corrected on this.

- Will I need a relay?

Yes.

- Is it important to use an inline filter before the pump? I already have one after the pump, before the carb

I'd recommend using a filter before the pump. If so you may be able to dispense with the filter between pump and carb, but I don't think that double filtration will harm anything.

- Where should I take the 12V power from?

I've attached a wiring diagram which hopefully will help. I had to do this for myself, to ensure I understood what I was doing (will be doing...) You need a switchable 12v source that is energised by the ignition. I chose the ballast resistor, but any circuit which is activated by the ignition being switched on is fine.

- What electrical connections are best to use? Spade connectors?

Insulated spade connectors (6.3 mm) of a size to suit the cable you are using. The ones that have heat shrink pre-applied are very good. VWP have them. For a tidy looking job, use heat shrink on all cable runs.

[peteracs]

Hi

Having had a quick look at the Hugo low pressure pump (I assume you have that?), I also noticed a comment re the Huco relay 132020, which appears to add engine non running cutoff as well as obviously allowing for adding the inertia switch. This relay, which is fitted to various moderns, appears to have a built in timer, so on ignition turn on it powers the pump for a set amount of time to allow the car to start. They are available pretty cheaply at around £20-£25.

On the Huco pump it takes max 5 amps, so 16 amp wiring is plenty.

If you need any help with electrics feel free to message me.

There are various refs in forums to this setup, here is a comment form one of them
(https://www.tr-register.co.uk/forums/index.php?/topic/70559-electric-fuel-pump/)

“Hi

Just fitted a Huco Fuel Pump (Hueco - German company now owned by Hitachi).

HUCO 133010 low pressure suction pump fitted in engine bay
Malpassi 85mm Filter
HUCO 132020 Fuel pump relay
Inertia swith (Ebay but with connector & flying leads)

Power feed from ignition switched battery supply, through fuse (7.5A, pump requires 5A max), through inertia switch to power contacts on relay (#30 & #87), to fuel pump


Relay control. Feed from Coil +ve (which is supplied from ignition switch) to #15. Contact #31 to ground (chassis)


The fifth connection  #1 takes a signal from the Coil -ve and enables the relay as long as the engine is rotating and the coil is generating a pulse via the distributor.


The fuel pump stops in any of


Ignition is turned off
Engine stops turning
Inertia switch is triggered”

[mangocrazy]

Hi Peter,

Is what I wrote correct, or are there errors in it? And I presume using a general purpose relay rather than the Huco one is still OK, even if lacking some functionality?

Graham

[peteracs]

Hi Graham

What you wrote is fine, just thought the extra safety with these purpose built relays was interesting to note and if you were buying new, worth the extra money.

Peter

[WestonE]

Hi Chaps

I would put the inertia switch on the earth side to the relay and have a 7.5amp in line fuse on the main power feed.

Buy the highest quality crimp tool and wire strippers you possibly can and tug test EVERY connection you make. I prefer the kind which have a separate insulation sleeve you slide on after the job is done. For inline fuse holders the blade type with water proof cover are preferable.
Everything you can do to have tidy well secured wiring with well insulated water protected connections will pay you back with reliability.

I have by now made 1,000s of wiring connections. I do not recommend soldering it leads to wire breaks later. Shrink wrap can be used to seal connections simply and is easy with little more than a disposable lighter needed. NB I use a purpose made heat gun these days.

Eric       

[mangocrazy]

Hi Eric,

Thanks for the suggestion. Is this amended diagram more representative of how you'd do it?

Graham

[peteracs]

Hi Eric

I did debate about the position of the inertia switch, but could see pros and cons both ways, but little to choose. Why would you prefer on the earth side?

Peter

[WestonE]

Hi Peter

A general principal of minimize the breaks in live feed connections with shorter direct runs. If a wire falls off on the earth side the circuit stops working. If it falls off on the live side sparks and blown fuses if there are fuses.

Eric 

[peteracs]

Hi Eric

Yes, good point. I had looked at it on the basis of length of wire run, rather than length of live run and connections.

Peter

[donaldb7]

Thanks for all the help guys.

I've order the relay now as well as all of the connection materials!

Will update you guys with how it turns out!

Cheers

[donaldb7]

Hi Eric,

Thanks for the suggestion. Is this amended diagram more representative of how you'd do it?

Graham

Hey folks,

Finally got some time at home and got round to fitting all of the components. Does it matter that the numbers on the Hüco relay don’t match up with the numbers on the diagram?

Cheers

[WestonE]

Hi Donald

Find an old relay and pull the case off. You will see a coil which connects contacts when it is energised (connected to power from a switch and earth). These contacts face each other in a line and when connected you can hear the relay click. When the contacts are closed it provides high current to the fuel pump. Most relays have a little diagram on them showing the contacts for the coil (feed from switch usually 86 & Earth usually 85) and Supply usually 30.

The relay is just a remote switch to keep heavy load off the switch circuit.

Eric   

[donaldb7]

Looks like the problem was in the relay! Must’ve been sold a bad one as a quick bench test shows that switch isn’t opening when hooked up. Will order another and cross the fingers!

[donaldb7]

Big thanks to everyone on this thread for their advice. I ended up taking a 12V ignition feed from the windscreen wipers so that I wasn't interfering with the ignition coil!

[squiglyzigly]

Hi Eric,

Thanks for the suggestion. Is this amended diagram more representative of how you'd do it?

Graham

I’ve had a little think about this and come up with an alternative as I’m also going this Huco pull pump route. (Should of been done by now but I got a duff new pump delivered).

My thinking is that maybe the inertia switch would be better positioned on the ignition coil and with the pump earth run through the relay connected to an oil pressure switch using a relay with a pair of normally closed contacts. (Usually black relays on various old fiats and lancias). The relay will need ignition live to hold it open when ignition is on and engine is stopped. Then as soon as oil pressure is achieved during cranking, the relay drops and the pump gets its switched earth to run.

My reasoning is that in a accident you want the engine to stop ASAP along with the fuel pump. (A bit like a modern car)
The inertia switch will stop the coil sparks and as soon as the engine has stopped it opens the relay via the oil pressure switch. And hey presto it’s all stopped. Engine, pump, the lot.
Modern injection cars will stop very quickly when the injection pump is cut off but a car with a carb full of juice will keep running for some time.

I completely agree with Eric’s comments about keeping live connections to a minimum and think this method also does that as you are only switching earths on and off.

Does this make any sense?

[peteracs]

Hi

Took me a few read through, but yes makes sense for carb car, not needed for FI as you say, though depends if you are wanting to stop the engine immediately rather than just having the pump turn off which is the main event to avoid petrol being spilt everywhere.

Peter

[JohnFol]

Would you extend the same logic to the fuel cut off solenoid buried in the carb?

[peteracs]

Hi John

I guess there are no down sides to doing that, so for me that would be a yes, good idea.

The only downside overall is if that pressure sensor fails, then starting would need a quick rewire.

Peter