1985 Series 3 Suspension / Fuel Pump issues
 

Hi I have a 1985 Series 3 Sovereign which we bought in 2005 she was in good nic for her age but always had a Mini Minor type ride on the back end very very firm and thudding. I have a good independent mechanic but he can be a bit easy going and wants to put XJS springs on the rear. I want the car to drive as it did when new or at least have the same spec of spring and shockers on it.

I continually see springs for sale for Xj6 but they seem to be sporty or bot correct so I am wondering if anyone here knows where I can get springs which match the original ones and shocks too?

I would really like to replace sub frame rubbers..springs ..shocks and get that back end and front too riding like it should.

The other issue I have had for a long time is the noisy crappy Bosch Fuel pump..its louder than the dam engine..my mechanic has complained to Bosch and they say its normal....I have gone through three of these things at $300 each...I would gladly pay more for one that does not make noise...again I wonder what the original one was?

I hope someone here knows where I can get my hands on the good stuff..Cheers Paul.
https://cimg8.ibsrv.net/gimg/www.jag...e92840ecdd.jpg
Our 1985 Series 3 Sovereign " Bessie"
https://cimg9.ibsrv.net/gimg/www.jag...77833e7b6a.jpg
https://cimg1.ibsrv.net/gimg/www.jag...c3f1f65fa1.jpg
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SNG Barrait Group is the supplier with maybe the best selection of original spec parts. I have to imagine the fuel pump should be Lucas and not Bosch. I see your car is right hand drive. Where are you located?

Can't help on where to buy springs. I avoid replacing them because too many others have reported incorrect ride height after doing so. Too many vendors selling 'almost correct' replacements.

From the pics, at least, your ride height looks OK so, personally, I wouldn't replace them at all. They are probably not the cause of your rough ride.

For shocks, most recommend Boge....but opinions vary.

Jaguar used Bosch pumps, and it should be virtually impossible to hear. If yours is loud I wonder if the rubber insulator is missing ...or similar problem....allowing noise to be telegraphed through the body

Cheers
DD

Hi,

do you know for a fact the rear springs and shocks have been replaced? That would have been a rare ocurrence. Maybe someone was trying to make the rear suspension "harder"? My 1984 built in 1983 still has the original springs AND shocks!! The ride is medium-soft. but softer than medium if that makes any sense! I would just replace the 4 rear shocks and see if that makes any difference. The original shocks were made by Girling Ltd. up to around 1985. Nowadays all you can get are the wimpy Boge shocks, equivalent to the US-made Monroe standard shocks.

As to the fuel pump, it is a Bosch pump with a Lucas sticker, that's all. It should be quiet, and you should only hear it "buzz" when engine is OFF and you turn the ignition switch to START.

In my experience replacing the fuel pump, I went through 3 used and new pumps until I found a quiet one. But $300.00 is way too much . There is a seller at eBay UK who sells the new Bosch pumps for $61.00 USD delivered. I ordered one but unfortunately it was also noisy.

Then I went to a salvage yard and pulled one from a 1986 XJ-6 and BINGO!!, it was quiet like the original pump was. I paid $6.00 USD (six dollars US), and that was 2 years ago, it is still working fine.

So, I guess it is hit-and-miss with these pumps.

My rear shocks on my ‘87 are original too and the car rides great. I did replace the front shocks because one was clunking over bumps.

Regarding the fuel pump noise, I can hear my fuel pump too but my issue is, the pump seems “normal” noisy when I’m using the right tank but when I switch to the left tank it gets twice as loud and starts vibrating. I have drained and rinsed both fuel tanks with fresh gas. I got a lot of rust debris out when I did so that was a worthwhile project. The lines are clear and so is the left return valve and the changeover valve. I even put a fuel filter on either side of the changeover valve. The noisy fuel pump persists using the left tank and now I’m afraid if I use the left tank, I’ll wear out my fuel pump. I was convinced there was some kind of blockage in the lines or the left return valve causing the pump to work harder using the left tank but that’s not the case. It makes no sense to me. Should I just replace the fuel pump next?

I sure don't know. A very unhelpful mechanic told me I had air in the system causing the fuel pump to make the noise. "Cavitation" he said. Chinese to me. How the hell do I bleed the air from the fuel system? I asked. No reply. Up your behind I told him.

I guess he wanted to charge me.

Danny:

I've no answer. Pump noisy on one tank, but not the other ! But, another pump is not likely to do any better. If the pump was bad, it would be noisy on either tank. I smell "occlusion" ! In the lines involving the left tank, or the changeover valve itself.

Jose :

I'm not quite that quick to condemn your unhelpful former mechanic!! In theory, any closed hydraulic system under pressure can have air. The fuel system included. Some musing might come up with a way to bleed it. At the regulator? Down stream from it, there is less pressure, and upstream even less. Leaking internaly the regulator???

My son was having FP issues on his Cummins powered Dodge. Leaky "quick" couplers !! Fixed hose and good clamps fixed it.

Now, my dead VIZIO ! My task for the day after chores and an errand or two.

Carl .

Carl, There is no bleed-the-fuel-system-from-air procedure in the Service Manual.

I'm not the only one conplaining about that mechanic, Saul of British Autowood also complained about him being so arrogant.

My conclusion is that the fuel system in the XJ-6 does not need any bleeding. We would know by now if it did.

Danny, I think Carl is right. It has to be in the line from the tank to the switchover valve or the valve itself is not opening all the way. I would blow out that line and bench test the valve. Blow into the left feed port and then apply power to the valve. Then do the same with the right side. One side should be open with power and the other side without. Be careful when opening the line as fuel will gush out if the tank has gas in it.

My experience of an XJ is that the rear springs last a very long time, and I had mine 14 years ! However the shocks are another matter. Nowadays the choice is much more restricted than in my day (car sold 2002). Supplier David Manners seems to have the broadest choice with prices from £31 to £88 for Konis and even £99 for SPAX adjustables. If I was a long-term owner I'd go for the Konis but it's is a lot of money as four are needed.

Thank you, both!

I agree with both of you and I had asked my mechanic to check the fuel lines and the return valve and he said they were clear. I don’t know if he checked the changeover valve. Maybe it isn’t opening all the way. We’ll check that for sure. I’ll post back after.

Danny

It needs bleeding, but there's no action for us to take. Jaguar took care of that for us :)

The air bleed is item #3 in the illustration below:

https://www.jaguarclassicparts.com/u...nd-hoses-trunk

I've never opened one up to see what makes it tick. However, it's plausible that an internal fault could create noise.

Cheers
DD

The fuel changeover valves fail mechanically but they also fail electrically. I found a fantastic write-up (check out the author of the article).

Fuel Tank Switchover Checklist, Series III XJ6

In my book any 30 year old Jaguar electrical connection is immediately suspect. Here is a photo of the wires going to the fuel changeover valve.
https://cimg1.ibsrv.net/gimg/www.jag...fee85301d5.jpg

The fuel return system on my 87 SIII has always has acted weird, changing symptoms from time to time. Finally got it up on jackstands and the wheels off. Turns out it was just the bullet connectors that supply the valves power and ground. Nipped the connectors off and replaced with new ones and voila, now working perfectly. We all know about corroded connections in our cars but all the discussion about faulty return valves had me convinced it was something more convoluted. The moral of the story is to check those connections first.


I had read several places that you can see the fuel returning to the appropriate tank by looking in the filler cap. It's very tricky but you can in fact see a metal tube down in there with a flow of gas much like a drinking fountain. Use a non-metallic stick (I used a popsicle stick) to hold open the spring loaded flap under the gas cap, then take a flashlight to take a look. The problem is that your head, the flashlight and your hand holding the stick are all trying to be in the same space at once. But you get lined up correctly and you can clearly see the fuel flowing in. I hope this helps.


Jeff

Curious. I propped the AFM flap open and turned the ignition to 'on' to see if the system was working correctly after cleaning the switchover valve in the boot yesterday.

I stuck a 3/8" wooden dowel down the fuel filler and thought I'd see a witness of return fuel striking the dowel - nothing on either side. Took an LED flashlight and looked down the filler necks and couldn't see anything either.

I closed the boot, turned the stereo off in the shop and put my ear to the fuel filler hole and could clearly hear the fuel flowing back into the tank. The noise came and went just as it should when the selector on the dash was exercised.

Just another way to see if everything is working ok, I suppose.

At times, ears are better than eyes? In my case, each compromised!! Perhaps with my newer "high tech" hearing aids??? Or with my brand new glasses and cataract in one eye gone?

But, yes, seeing an almost clear liquid in a confined space???

Decades ago, as I worked in the cabin on my engine replacement, working on the electrics, I thought I heard the fuel pump !! Naah, the radio was "on". volum way down!!!!

Carl

Was looking at a house we had painted yesterday, and my wife was pointing out spots in the wall paint where she thought the paint job was defective. I could only see a few of them.

Looks like in my old age I'm only going to be able to diagnose problems where I can both see and hear them.

Of course the fact that the more paint problems she pointed out to me meant more touch up and repaint that I'd likely have to do get it looking right - I'm sure that had nothing to do with whether I could see them.

Phil

I replaced my changeover valve and now the fuel pump sounds the same using both tanks. I do think my fuel pump is on the noisy side but at least it isn’t noisier using the left like it was. The only difference I hear now is I think I can hear the changeover valve buzzing using the left tank but not the right. I assume that’s normal.

Thank you for the advice JagCad and Yellow series3!

Danny, when everything works as it should, there should be no noise, zero, nada. I'm thinking it is the pump. I went thru 3 pumps. The third is completely quiet. No more buzzing after the system is pressurized.

There is an article about opening up the these pumps and fixing the noise, I just can't find it.

It’s pretty loud. I can hear it inside the cabin. I guess it’s time for a new one. I’ve redone everything else with this fuel system, why stop now?? :-/