electric fuel pump

[bigg_vin]

just wondering how many of you out there have changed your fuel pumps. i have a 253 VH, and am looking at putting in a holley blue pump. would that provide adequate figures for my engine?

any advice?

[bigg_vin]

..........................*bump*.................. ...............

[253@7k]

should be fine for a 253, you will also need a fuel pump block off plate.
Then its just running a line to the pump and then to the carby.

What carby are you running?

[bigg_vin]

block off plate?

its the stock quadrajet

[253@7k]

You will need to remove the mechanical pump. (not needed)

This will need a block off plate to stop all your oil coming out.

Search on ebay if you want an idea.

[bigg_vin]

ah, you can leave the old pump in though yeah?

and would you reconmend mounting the pump somewhere other than under the hood, or it wont matter?

thanks

[253@7k]

You can leave the pump but why? It will just sit there and pump air.

Yes mount in engine bay or you could go under the body on the chassis but I would not recomend it.

[bigg_vin]

you wouldnt reconmend the chassis? so it wont get too hot under the engine?

i will end up removing the pump, but i am planning on installing the holley tommorow, and i dont have a blocking plate yet!

the power to the pump needs to be with ignition on only yeah? or can you run straight battery power?

also, it goes, tank - filter - pump- regulator - carby correct?

thanks

[253@7k]

It will just get battered with crap on the chassis. If you get crafty then you could make a block off plate and weld a bracket to it for the holley pump. Yes will need to go to the ignition though I would recomend using a relay. (ask if you need wiring diagram) And yeah that is the correct order.

[bigg_vin]

do you have a wiring diagram with the relay?
that would be fantastic.....

i am planning on installing my immobilizer relay on the fuel pump, so will the one relay work?

thanks

[bigg_vin]

also, any hints on the best place to draw the 12v ignition where the voltage wont drop to 0v whilst cranking, cos im guessing if it does drop to 0v, then the pump aint gonna work, and the engine wont crank!

i cant really go through all the wires in the wiring harness at the moment, cos i cant connect my battery......

[253@7k]

Sorry it took so long my comp just shat itself for some reason. Wierd, rare occurance with mac's.

here, just put the power to the starter motor insted of battery.

[253@7k]

Oh and dont laugh, I am not good with wiring diagrams, just so long as you can understand it.

[bigg_vin]

nah its fine, nice and clear.

so i do need to use two relays dont i......

any ideas about the ignition 12v source?

thanks

[bigg_vin]

so, started motor solenoid gets 12v only when ignition is switched on? can i tap into this for the 12v igniton source?

[bigg_vin]

do i have to use a relay? in this situation, why did you reconmend using one?
thanks

[253@7k]

Ok, talked to some mates, you should just be able to connect to the battery, failing that the + on the starter solonoid? will be fine.

As per relays. Yes use relay because power from ignition may not be adequate. A relay uses asmall current to connect a big current so when the ignition is turned on it will trigger the relay to connect the direct current from the battery.

The second relay (immob), that is your immobiliser switch. (power comes on when immob is pressed/turned off). That should cut through your ignition wire somewhere so when immobilised the fuel pump will not work. I think thatis what your on about.

Steve.

[bigg_vin]

ok, all is going well. i am about to connect the new fuel line to the carby.... do i need to do anything about the fuel return line that is currently there? or can i just "piss it off" !

[253@7k]

Fuel return????????

Carbys dont have them.

[bigg_vin]

yeah thats what i thought until i looked into it...

i noticed a small, must be low pressure, line going back into the fuel lines before the filter. where the metal fuel line joins to the carby, at the front, there is a thing that looks like a small vac diaphram, there is apparantly an inbuilt filter here, and the line coming from the little nozzle of the "vac diaphram" is labeled as a fuel return line in the gregorys manual?

i should be able to just block it i think

[Emski]

hey mate i have one in my 308 vk, and they are pretty reliable, but it may be an overkill for a 253, but if you do get one , make sure you get a regulator, and set it to 4- 4.5psi, goodluck

[bigg_vin]

how do i know what it is set at from the regulator?

also, when you were installing the connectors and fuel line, how far in could you screw the connectors? i could only go half way then i was scared of cracking the housing so i stopped.....

[bigg_vin]

ive just been reading about the holley blue, and it says that the fuel pressure regualtor is pre set at 14psi... which is slightly high for my application....

does anyone know round abouts how much to turn the lock nut anticlockwise to decrease pressure without using a fuel pressure guage....cos i dont have one!

thanks

[Emski]

hey buddy i should have added you need a pressure gauge to tell you the psi level, a holly needle and seat will only handle 9 psi, so 14psi is way to much but the pressure gauge will tell you where your at, to answer your other question from looking the fittings go about 3/4 the way in i used abit of plumbers tape to get a good seal, no leaks to date, good luck

[bigg_vin]

ok... connected everything up....

nothing works.....!!!

the pump would not even turn on.

i gave the pump direct power after trying to get it to turn on with the ignition
but even this did not make the pump turn on

any ideas?