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Fuel Pump GRRR


Shackleton
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Err was all ready to fire the 3.9 for the first time. Turned the ignition on - loads of relay / stepper motor noise etc... excellent.

Turned ignition to crank - nothing, not a peep. Eventually found a rogue live that I'd missed when connecting the starter wiring - sorted. She's cranking beautifully.

Wanted to get an audible confirmation from the fuel pump, so got a pal to stick his ear in the filler - nothing. Checked the fuse and it was blown so threw another one in and it popped as soon as I turned the IGN on.

After a number of checks and five 10amp fuses later I still have the problem. A very friendly mech came up and said that the pumps can jam if you have them out and jostle them about. I did have the pump out cause the live terminal atop the pump was loose so I re-soldered both terminals.

Now I'm thinking maybe I mixed them up - that'd blow the fuse straight away wouldn't it???

Other stuff is the 3. 9 exhaust will foul the LT95 and will need to fine fettling to make the full system sit right, the 3.9 rad will foul the battery clamp if you don't pare down the O/S rad mount bracket - the alternative being use one of the less substantial later battery bracket and lastly make sure if you've taken the amplifier off the distributor that you put it back on first less the inboard bolt, then mount the P/S pump bracket and bolt it up and lastly offer up the remaining amp bolt - a tip is to cut a grove in the bolt heads with a hack as a screwdriver is a much easier way of tightening these tiny bolts...

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Re the fuel pump (internally) the termainals for + and - are different sizes, so unlikely you have then mixed uop, top wise they can be switched around but again are you sure you have done this as its clear which is which ?

Re the Hotwire there are about 3 wires you have to connect

Big wire - Main power

Cranking and ignition feed, the fuel pump is driven by the ECU

I can't for the life of me (years and years ago) remember all the colours, I think Big Brown Main power, red white cranking and white Purple fuel pump but maybe you best bet is to post up here the wires and colours on the HW loom and what you have connceted to which, then it will make sense

Should be an easy fix methinks.....something simpleish :)

Nige :blink:

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I thought hotwire was much fussier than flapper?

The connections to get flapper working are:

Brown Battery + (Permanent Live)

White Switched 12v from ignition (on when engine running)

White / Purple feed to Fuel pump

White / Red Start / Reset, to the starter motor solenoid feed, on when cranking. (Not always needed)

White / Black or White / Blue To ignition amplifier TACH feed (if you have one) or -ve side of ignition coil

Black There are several earths on the loom with tags, they MUST be bolted to a good earth.

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Thanks guys - no I have her turning over, thats now sorted.

RE the fuel pump - I had it off to resolder the live wire into the top of it - but there was signs of corrosion at the terminals so I pulled both wires off cut them back a bit and resoldered them both on.

I distinctly remember going 'oh carp which way around were they' and came to what I thought was a fairly sure conclusion.

Now I'm thinking I must have gotten them mixed up, what I'm relaly asking is if I have actually reversed the polarity would the symptoms be an instantly blown fuse?

I'm such a dumbass :D

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Now I'm thinking I must have gotten them mixed up, what I'm relaly asking is if I have actually reversed the polarity would the symptoms be an instantly blown fuse?

Maybe, it depends if one wire earths through the pump body as well as the earth wire. Measure the resistances to earth of both legs - if one is dead short then that's the earth leg. Or your pump is deaded :(

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Don't think it should blow a fuse. If you reverse the polarity the pump would just run in reverse....

Thanks guys - no I have her turning over, thats now sorted.

RE the fuel pump - I had it off to resolder the live wire into the top of it - but there was signs of corrosion at the terminals so I pulled both wires off cut them back a bit and resoldered them both on.

I distinctly remember going 'oh carp which way around were they' and came to what I thought was a fairly sure conclusion.

Now I'm thinking I must have gotten them mixed up, what I'm relaly asking is if I have actually reversed the polarity would the symptoms be an instantly blown fuse?

I'm such a dumbass :D

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