I have 1977 XJS Lucas ignition.

Has been in garage for many years.It turns over and there is spark.

I have disconnected fuel line at fuel filter to see if ant fuel delivered and no fuel is pumped on cranking.

Electrics to fuel pump seem ok I have connected multimeter to monitor ignition sequence and voltage is delivered to pump on ignition.

i have removed old pump and replaced with new pump as i thought pump was dead.

Refitted new pump same issue no fuel pumped.

Any ideas?

 

Stored car, long list.

Best way at the moment is establish if fuel is gravity flowing from the main tank, to the small supply tank under the battery. If this is OK, next is to establish gravity flow from that small tank to the inlet of the pump. If that is OK, then establish that fuel is being spurted out of the outlet spigot of the pump with each ON of the ignition switch.

STATING THE OBVIOUS.

You will be messing with raw fuel, so PLEASE take the required precautions. You dont want to set fire to it just yet.

Next:
Remove the pump, observe the + and - terminals on the bottom. Ensure the wire with 12v in it when the Ign is ON is connected to the + terminal. NO I AM NOT BEING A SMARTY, some pumps have the large terminal as the + (normal), and some have the large terminal as the - (not normal). I have been caught out. The pump will run either way, but only pump fuel in the correct terminal placement.

Next,

Fuel filter, replace it, again taking care it is fitted the correct way round.

Next,

Remove the fuel supply hose AT the fuel rail, remove the fuel hose AT the fuel filter, and supply compressed air to that line. I suggest the engine bay end be extended outside the engine bay, as some crud could do some harm.

Next,

Look under the car, on the RH side, and just on the inside of the front and rear jacking points is a steel pipe. That is the fuel SUPPLY line from the rear to the engine. It gets damaged by silly people jacking the car without using the supplied jacking points.

There is a similar pipe on the LH side. It is the RETURN line from the engine to the tank, and yes, it also gets damaged.

IF there is significant rubbish blown out with the compressed air, I suggest the fuel rail and injectors be removed for proper cleaning.

After that you should have fuel AT the engine. Then comes the magic of Injector pulse, and with the PreHE that is a special item indeed, and can be discussed when and if needed.

 

Ok I will run through this list.

Thanks

 

Every thing Grant said , my 77 was stored for a long time and found that the metal pipe from the tank to the pump, was blocked solid, it took a fair while to unblock it with all sorts of wire prods before it cleared . Firstly I drained the tank then cleaned it through the tank sender as I did not want to remove it, then worked on the metal pipe and then flushed the tank and fitted a temporary filter before the pump . Do not make the mistake of turning the engine over before going through the process Grant has said .

 

Ok i have had a productive day.

Ran through the list.

Good gravity feed to fuel pump.

Removed pump from holding bracket and inspected wiring and polarity.

Connections were to the correct terminals but the live wire had pulled free from the connector so no contact.I think this is because the replacement fuel pump Goss GEO34 is larger in size than original Lucas pump and when I refitted it it had too much tension on that lead and came apart form connector.

So I freed off some slack wire to give more play on the pump and recrimpped the wire to the connector.(I know I should solder but couldnt get that happening)

Disconnected outlet and ran pump and it successfully pumped fresh fuel .

Reconnected outlet hose and disconnected hose before fuel filter in the engine compartment and fed into small milk bottle.

Cranked engine and 2 small bottles of very red and syrupy fuel expelled.

3rd crank and fuel was fresh.

At this stage I was a very happy XJS mechanic !

Reconnected hose at fuel filter and cranked engine again.

3 leaks noticed in engine bay 2 from loose hoses on injector rail.

3rd leak from hose just after entry to engine bay through firewall.

Dismantled air cleaner for greater access and examined hose and seems ok.

Now i am guessing I have hole in metal fuel line at firewall or behind.

It is spaying into engine compartment so the leak cant be that far down the line I think.

Any ideas on this much appreciated.

I am rating today as good progress but a little concerned about fixing this leak .

Cheers

 

Well done.

Certainly a productive day.

A strong suggestion from over here. Replace ALL the fuel hoses in the engine bay. No matter how "good" they may look. The V12 will catch fire in less than a heartbeat, and I am over rewiring these cars now, age related, but I have done 7 to date, and fuel line weeps, quickly becoming a leak, caused all of them.

I doubt the steel pipe is the root cause, and it is fiddly to get at. If it is the fault, I would simply cut it off near the front jacking point, attach a hose to the engine bay piece, and pull it out thru the engine bay, 2 person task, and thus drag the hose with it, and reconnect using good old Melbourne imagination, haha.

 

YUP, great diagnostic path. I can only add a caveat, probably unnecessary, but, I'm quite "fire sensitive". My former profession lingers.


Use only top grade FI hose and shield it with metal for impact protection if possible.
Or up a notch and use braided FI fuel hose.


Carl

 

Ok I have been busy and now I am finally getting round to replacing the fuel hoses.

I am confused as to what diameter hose I need.I have read on these forums both 9/32 or
5/16 .So that is 7mm or 8mm as far as I can see.

Any ideas on this would be appreciated.

 

PreHE is 5/16, which is sold as 7.5mm EFI rated hose.

Brands vary with their stamping. Goss is usually 8mm, and is fine.

Dayco is 7.5 and also fine.

Chinese stuff, all over the place, and should say in China.

 

Hi All

I have now completed the fuel line replacements and are pleased to say this has been a good process with great help from you all on this forum.

Turned engine over and it fired and ran for very short period and then I retried a couple of times and had same result.I stopped the cranking and let it sit for about 20 minutes then tried again and it fired and get running.Maybe I had flooded it the first time.Anyway pretty much starts up and runs on the first crank now.

So what next ?

I do not think I have any transmission at this stage and the wheel nuts seem like they will not shift.

I am thinking I will need to drain the transmission and replace the filter as a bare minimum.

The wheel nuts are worrying me as I dont have a wheel brace in the car and I cant seem to get a socket to fit well enough to get some strong action ,

Cheers for now.

 

The wheel nuts are 22mm. Use a single hex socket on them, and if they will not shift, get an electric impact gun (a rattle gun, as used, though air powered versions, in tyre changing places). Do not just use a very long lever or you stand a good chance of sheering off the stud.

 

Thanks Greg

Much appreciated I will try the hex socket .I am glad you have cautioned on the long lever as I was heading in that direction.

Cheers

 

Well done on a running V12, drinks all round me thinks.

Get some Diesel fuel, and ATF (Auto trans fluid). Mix it 50/50 in a spray bottle. Spray the wheel nuts, really soak them, have a beer or 3, soak them some more. Sometimes they grow to the alloy wheel, as well as the stud, so as Greg has said, take your time.

Trans fluid and filter would be a very good idea. that will be fun.

Whenever you start thr PreHE, DO NOT shut it down, unless some serious issues require a quick shutdown, until some heat is in the engine, usually 5 minutes. They will flood. Yours probably has "cold start" Injectors??, if so, remove them, both mechanically and electrically. They are not needed, and reek havoc.

Well done again.

 

Grant's mixture a great plan, but I say make it 33% diesel,33% ATF and 33% acetone.
Greg