Hi guys,

I have always much benefited from reading threads on this forum but now I have my own problem to report:

Last night I was with my girlfriend driving to her dorm when, all of a sudden on a busy expressway, the Jag just stopped giving gas. The engine stalled and I needed to be towed back home. When I got home, I read DTC P1775 and P0727. The Anti-Lock MIL was also illuminated. The car turns great but will not start.

I should note that I have been having the turn but no start problem intermittently for the past couple of weeks. I assumed it was because I had left the alarm on and had not driven the car and it had drained the battery. If I have the car some gas on Engine start, it would start and hold, but if I didn't, it would sputter out and die.

Am I correct to assume that my fuel pump is bad? Is there anything else I should check? Also, has anyone done a DIY fuel pump replacement for the 95 XJS?

Thanks in advance guys, you're awesome.

Taso

 

Not real familiar with the 4ltr XJ-s, hardly any down here.

The symptoms point to a fuel pump issue, and or a blocked (old age) fuel filter.

Not knowing the mileage travelled, I will also suggest the CAS (crank angle sensor) may be on the fritz, they do that. Simple check is to watch the tacho whilst cranking, if a 200RPM indication is seen, then the CAS is deemed OK, but not always. No tacho reading, CAS is dead.

Fuel pump is inside the tank, so tank out will be the required fix, not hard, just time consuming, and fiddly.

 

Thanks for replying, Grant. I ordered a new fuel pump and I'm planning on having a mechanic install it when it comes in next week. I'll write back with my status after that, hopefully the issue is solved.

Thanks again!

Taso

 

One more question:

I know that the Fuel Pump Relay is located in the Right Rear component panel of the XJS. Can someone tell me where this panel is on the 95 XJS Convertible? I checked the trunk and removed the carpet on the right side but was unsuccessful in finding the relays.

Thanks again,
Taso

 

There is a carpeted cover in the right rear of the boot (trunk) There is a little slotted cover connector, rotate it and pop open the cover. There are a number of components there including three relays, two blue and one silver. The silver one is the fuel pump relay.

I would definitely check that first before replacing and components.

Cheers,

Allan

 

An Aj16 that will not start...

Crankshaft possition sensor mentioned above

Fuel Pump relay mentioned above

Tripped inertia switch (did you go over a bump or did your girl touch anything on the area between her door and her knee bolster either with her hand or foot?)

I you drive your car in wet conditions water could have dripped to the ECU too

Good luck

 

Hi guys,

First of all, thanks for the replies.

I have attached a picture of what I see when I open up this compartment. Am I looking in the right place? I don't see any relays, be it blue or silver.


Where in the engine can I find this sensor? I was reading about it last night but I want to be sure I can locate it when I pop the bonnet.

I checked the inertia switch and pressed the button to reset it to no avail.

I don't think that it is the ECU, though.. I have never had any type of water problems with the car and every other system works. 30,000 miles on the car.

Thanks in advance!

 

Oops sorry, when you said right rear component location, that is the location but the relay is actually above the right wheel arch. Take the battery cover off and then the carpet panel to the right of it to expose the wheel arch. Stick your head in and look up and you will see the relays. The silver one is for the fuel pump.

With covers off


Looking up over the wheel arch

 

I see, thanks for the reply! Going to check it out right now.

 

The CPS is on the front of the engine mounted above the toothed ring on the front of the crankshaft.

One way to test it is to look at your tacho when you crank the engine. If your tach registers 200 rpm your CPS should be fine. If the tach doesn't move your CPS is probably faulty.

Cheers,

Allan

 

Checked the fuel pump relay, seems fine. Clicks when it's supposed to.

Checked the CPS as well. While cranking, 200 rpm is registered on the tacho, so I guess it's okay.

I went ahead and ordered a new Bosch fuel pump and I'll have the car towed to a mechanic to install it when it comes in. I'll also have him change the fuel filter while it's in the shop.

Updates to follow!

Thanks,
Taso

 

Taso,

Before going to the expense of having the pump replaced, have the fuel pressure checked at the rail. Your fuel pump may be fine and you may be experiencing other issues.

With these cars it is always better to take the time to actually diagnose the problem rather than throwing parts at what you think might be the problem. You can be chasing your tail if you don't

Cheers,

Allan

 

Hi Allan,

Thanks for the advice. When the car gets to the mechanic, I'll have him check the fuel pressure at the rail before going any further. Appreciate the input!

Best,
Taso

 

Is there a way I can check the fuel pressure myself before bringing it to the mechanic? What does the procedure entail?

 

Yes you can if you feel comfortable doing so. You will need a fuel pressure gauge. You can buy one or some auto parts stores will loan them out to you. I'm not sure on the AJ16 engine wether you have a schrader port connector or not for connection.

Basically you have to depressurize the fuel system by removing the fuel pump relay and cranking the engine a few times, then refit the relay.

With the fuel system depressurized, connect the pressure gauge to the fuel feed. Then crank the engine and see if you have fuel pressure and how much. If you have pressure and it is in spec for your engine, your fuel pump is operating. As always when working with the fuel system, be VERY careful, as fire risk is increased.

Do you have a service manual for your car? I highly recommend you buy one and familiarize yourself with the car's systems and components. The manuals will give you step by step instructions on how to repair or replace most of the systems on the car.

Cheers,

Allan

 

Just dropped the car off to a reputable Jag mechanic in NYC. I'm convinced that it's the fuel pump, but let's see what this guy says. Also getting the fuel filter changed. Since the car just hit 30,000 miles, I figured it would be a good time for transmission fluid change as well. Keep you guys updated on the repair!

Best,

 

Hey guys,

Picked up the car from the shop a couple of days ago. So far so good. Had the fuel pump and fuel filter replaced. I also had the transmission fluid and filter changed.

Only problem I had was that the guy who did the repair claimed that replacing just the fuel pump without replacing the whole module would lead to certain future failure. Should I believe that, or do you think that was something he said only because I supplied the fuel pump myself?

Anyways, he charged me for four hours of labor for the job. I'm happy because at least it seems to be running well with consistent starts.

Best,

 

Taso,

Did he actually diagnose that the fuel pump was faulty or did he just change it because you gave him the parts and told him to?

Cheers,

Allan

 

Hi Allan,

He independently diagnosed it as the fuel pump. I had the car towed to him and told him that it cranks but won't start. He called me back a few hours later and told me it was the fuel pump. I brought the part to him later that day.

Best,
Taso

 

Cool. When you say module, I'm assuming you mean the whole pump housing that contains the pump, filter and seals? Is this not what you provided him? Or did you just provide a pump alone?

Cheers,

Allan