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-   -   series 2 fuel pump not engaging when cold (https://www.jaguarforums.com/forum/xj6-xj12-series-i-ii-iii-16/series-2-fuel-pump-not-engaging-when-cold-119897/)

Nic Graves 06-15-2014 01:30 AM

series 2 fuel pump not engaging when cold
 
Hi I have a 78 Daimler soveriegn, when the car is cold the fuel pumps are not kicking in when the ignition is turned on. After 3-4 attempts at starting the fuel pump will start humming away, and sure enough the car will fire up. Has anyone encountered this?

Thanks

Grant Francis 06-15-2014 03:27 AM

Yep.

Down below the oil filter you will find the oil switches.

One, largish, is for the gauge.

Second, usually below and to the side of that one, and is smaller (like any other idiot light switch) does the oil light.

Third, is slightly towards the rear of the oil filter mounting alloy block, and generally screwed directly into the engine oil gallery, looks the same as the other oil light switch, but it is NOT. This one is for the earth of the fuel pump relay, and works in reverse to the "normal" light switches. This one has EARTH when oil pressure is present. The oil light switch has EARTH present with NO oil pressure.

Simple fix is to remove that wire, change the terminal, and earth it under any convenient screw/bolt. That way, the fuel pumps will operate whenever the ign is ON. Some dont like this, choices we make in life. The car still has the inertia switch for impact protection. My S2's have all been that way, and no BBQ Jag to date. The older ones had no such switch, and the pumps simply "ticked away" whenever the ign was on, and never had any issues that I remember.

Those switches are probably still available if yopu want it as made.

Nic Graves 06-17-2014 04:25 AM

2 Attachment(s)
Thanks Grant, I had a look at her this afternoon. It seems to have only 2 switches the large one slightly to the right of the oil filter (if looking down) and the smaller to the left, Which i assume is the one i should be looking at. It has one cable, (earth, green/yellow) with a push on terminal. Maybe the warning light switch is part of the oil pressure switch on this model?? Just making sure im looking in the right place before i dive in!

Cheers for your help!

Nic

Grant Francis 06-17-2014 05:57 AM

OK, first things first, my apologies, I got it part wrong.

Went to S2 today, rescue mission, turns out he ran it out fuel, he will pay, trust me.

Looked at the switches, coz it had no fuel pump activity, and that is when I realised teh blunder.

Rear of the oil filter mounting housing, is an alloy block attached to the engine by a banjo bolt. This houses the 2 oil switches, one for the gauge, and one (in the end) for the light. Now, to rear of that is another switch screwed directly into the engine block oil gallery, this is the fuel pump relay earth switch.

I have tried to find a drawing of it, but no luck. The one is the snap is the light switch I think. Test it by removing that wire, ign ON, earth that wire, see if the light comes on, or the fuel pumps start.

The car I went to had the oil switch for the pumps basically under the rear carby (as a rough area guide), and the wire was earthed close by already.

Hope that clears things up a tad

Nic Graves 06-17-2014 06:51 AM

Thanks ill let you know how i get on!

Nic Graves 06-21-2014 03:00 AM

Hi Grant, turns out the switch in my picture is for the fuel pump. I earthed it on an engine mount and she started first pop. Thanks for your advise brilliant! I am on the look out for a replacement switch, as id like to keep her original but for now its a great fix.. Thanks again.

Nic

Grant Francis 06-21-2014 04:19 AM

SWEET.

Look around, I reckon I saw them on one of the Supplier sites I troll from time to time. Try JagDaim in Melbourne, SNG BArratt UK, or anyone over there in NZ that still has stock of Quinton Hazell/Unipart stuff. Triumph and I think? Rover, also used that same switch.

If I find a link, part number I will let you know via here.


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