OK, hereÆs the story as best I can remember it all.

I got my Æ90 XJS Convertible about a month ago and have been driving it around enjoying the ride and the southern California sun. No real problems except that the transmission would not kickdown, the cruise control didnÆt work and it never showed a ôFast idleö (always right on 750)
Last Sunday, after reading a post by Doug Dwyer about how easy it was to fix the kickdown problem
(ôSo, I did some exploring and discovered that the little round plastic throttle stop below the throttle pedal was adjustable. I screwed it inwards several turns. Now the kickdown *really* works.ö DD)
I decided I would go fix that problem. I adjusted the little plastic thingy. Then I went exploring around under the bonnet and found the three-conductor plug going into the cruise bellows was partially disconnected. I seated it properly. Then while looking around some more I found one vacuum hose off the Vacuum Solenoid Valve. After hooking that back up I closed the hood and headed for the highway. (About a mile and a half, or so) After getting on the freeway and up to about 55 I went to WOT. The kickdown worked!! (I was suitably impressed. I instantly understood why I bought this black beauty. Then almost as instantly (I was up to about 80) the engine stumbled and coughedàtwice. I grabbed the next exitàshe seemed to be doing all rightàso I turned her around and headed back. I tried setting the cruise at about 60MPH and it worked also!! But, once again, just as I was getting that ôHighö from something working rightà she coughed again. From there on it ran fine, as long as I didnÆt move the gas pedal. TPS pot my rookie brain said. So I took it home and checked the Pot ~.2 Volts. So I said Aha and adjusted it. Seemed touchy to me, but what do I know? Took it for a 100-foot cruiseàstill hesitates. So, after buying a new one of those (must be golden) potsà I installed it adjusted it (much easier this timeàSet to exactly .320 Volts) No real change to the symptoms if anything, they got worseàdidnÆt really want to idle, considerably more sensitive to gas pedal movement. After fooling with re-breaking some of the things I fixed. With no improvementsàit now doesnÆt want to run at all. It will start and idle for around 1 û 2 seconds then die.

Does anyone have any words of wisdom for this bewildered Jaguar Novitiate?

TIA

Mike Smith

Submitted by fccm.sw@cox.net on Tue, 07/06/2004 - 17:29

Looks like #3 wins. I had a bad pump. Whir.........whir.........whir, etc with the relay jumpered. It Would kind of pump the rail up, but didn't have a chance of keeping up with a running V-12.

A NAPA store in the area actually had one!!!
So, on sunday morning on the fourth of july in the USA I was able to buy a XJ-S fuel pump!!!

Well, at least they thought they had one. I now know why they had it. Someone bought it, found the fittings to be wrong (the electrical connections are wrong also) and gave it back.

I did buy it and I managed to change the fittings so that it fits and my fuel rail pressure maintains 45PSI under all conditions. (I rigged it so that I could drive with the pressure gauge connected. The pump is NAPA Brand part number P60423. but, if you use it, remember you are going to have to get some hose barbs of the correct size to fit it.

In order for me to feel warm and fuzzy about my pump I intend to order me up a Genuine Lucas part. It would appear the original lasted 14 years. If, I can get that out of a replacement, I will be happy.

Even though the filter seemed clear, I will replace it also. All I know about it is that it isn't the original (it is Bosch brand)

Mike

------------------
Mike

'90 XJ-S Convert
'79 MGB LE

Submitted by NE52-32043 on Tue, 07/06/2004 - 13:53

Mike,

Any luck locating the problem?

If the pump is working, you should hear it in the boot when you turn the ignition on. I'd still check the fuel filter. And the pickup in the tank for corrosion blockage. It's more common than you'd think, especially if the car was sitting around at all.

A good source of information on how the fuel system is pieced together is the parts catalogue, believe it or not. It's got detailed pictures of all the components and shows how they piece together. Check the connections on the fuel pump and in the fuse box. As I recall, there is a ECU in the boot as well that calls for fuel. Connections there can be corroded or loose as well. Obviously, if the fuel pump itself is bad, that could cause the problem. Be sure to replace that fuel filter in any event.

Let us know what you end up finding.

Steve Weinstein, JTC-NJ
'72 E-type 2+2 (for sale)
'70 XKE FHC

Submitted by fccm.sw@cox.net on Sun, 07/04/2004 - 00:55

Steve,

Thanks for the help.

After spending way too much time rigging a connection for Fuel pressure monitoring... I have determined that I have no pressure. After turning the ignition on and off multiple times the needle did not even move. I would assume that my pump is not working at all. Tomorrow I try to figure out why.
I would guess the options are:
1 the relay is never being commanded on... is this even likely?
2 The Relay is broke.
3 The Pump is Broke.
4 There is a broken wire/connector somewhere.
5. A fuse? (are there any specifically for the fuel pump?)

Anyway, at least now it appears it is once again Lord Lucas' fault... and he and I are old friends.

Thanks for the help, so far, and if anyone wants to chime in with more suggestions, I am still listening.

Mike

Mike Smith
90 XJ-S Convertible
79 MGB LE

Submitted by NE52-32043 on Fri, 07/02/2004 - 10:37

Did you check the fuel filter? I've had similar problems with several cars and it is almost always the fuel filter. Your car is 14 years old, and the gas tanks in the XJS are notorious for corrosion. It's possible you've got some junk being sucked up and blocking the filter. It's worth a check. Also, check the connections on the fuel pump and make sure that they are not corroded/loose, etc.

Just a thought.

Steve Weinstein, JTC-NJ
'72 E-type 2+2
'70 XKE FHC
Former '89 XJS Owner