Hi there, as per other threads, finally my fuel pump is having problems.
Description of the problem:
when just started from cold, the fuel pressure goes to sharp to 32psi, at 1k rpm and when hitting on the gas pedal reaching the 3k rpm, it goes to 25psi sharp. After a while when hot, the needle start oscillating from 25psi to 32psi. , and as the time goes and the engine start heating on, it oscillates and lower and lower fuel pressure level, so as when hitting the gas pedal the fuel pressure goes to 10psi and lower, when releasing it after a few seconds goes back to oscillating at 25psi.
sorry for the long story, my fuel pump is boiling or something like that, the odd is that fuel pump assembly ($800) was changed (at least i paid for it), like 10 months ago.
seems to be a really bad design at this point.
as im jobless now, and i have the time to fix the problem myself i need help:
It seems more appealing to me to install a secondary external in line fuel pump instead of removing the fuel tank, and change the one is failing there, I'd i like your expert advise:

1- is it recommendable to go for the secondary in line Fuel pump under this symptoms ?
2- in case (1) is yes, what is the best location to install it (under the hood, or below the car )?
3- in case (1) is yes, what is the most recommendable pump model/brand/capabilities to do the job ?
4- in case (1) is yes, where do you recommend to extract the energy/voltage from, (i guess it will be in the hood, can i do it using one of the relays are already there?).

thank you
Jaguar XJ6 1993, 4.0L
Martin

 

I'll apologize for not reading all your detail, a bit short on time here.

You can't pull through the in-tank pump with another pump, if the in-tank pump is not operating.

 

you mention the <B> in-tank Bosch fuel pump</b> in other post, is that suitable for XJ6 /XJ40 1993 4L ?
what is the best fuel pump in-tank i can install in my car (model / brand) ?

thank you !!!

 

No, people are not reading what I wrote. The in-tank pump is a Walbro original manufacture, and that same brand can be purchased as an aftermarket replacement.

The Bosch pump is fitted externally to earlier 1988-1991 XJ6.

 

thank you very much !!!

excellent help, I owe you a drink, if you came down to Florida, let me know !!!

I will start with the replacing job asap !!!

 

not yet, will start the working by next week.

 

Note that the aftermarket replacement pump does not include the funky o-ring in the bottom of the canister. If that o-ring is damaged the fuel pump will not pick up fuel. You won't get a refund on the pump because the pump works. We have looked for years trying to score that o-ring and haven't found them yet.

Have you had any luck finding those, JTO?

 

This weekend i took the car to a friends house and after lifting it , changed the
fuel pump (& fuel filter just in case...), jaguar designers did not make it easy to change the fuel pump !!!, (still I do not understand why they did not use an external Fuel Pump....)
I measured Fuel pressure, and it oscilates on the 30psi, when acelerating it goes to 35psi !!!
left it on iddle for 2hs, and its still perfect !!!
IM SO HAPPY !!!!

next troubles:
step 2: i have FUEL FAIL 12, as an error code, in internet i found that it is the MAF...
should i change it or just remove and clean the connections.... could that work ?

step 3: i have an electricity leak (if i leave the battery connected it will discharge in 4 days). any clues where to start ?
std procedure ?
measure electricity consumption and start removing fuses until the leaking stops, then continue narrowing the problem...

thank for all your help !!!

 

Battery drain.
STD procedure start with the Battery get it properly tested to see if it is any good before doing anything else. (Assuming that you don't leave the lights or anything else on whilst the car is not running).

 

Good for you Martin, I'm glad you followed the advice. The in-tank pump design got rid of the hot fuel cavitation problems that plagued the earlier style. Adding a second pump on a later car with an in-tank pump doesn't work, you have to change the failed pump.

 

now the work is done, im happy, but in the middle of the process i was regretting just having started with it.
.... By the way, thank you VERY MUCH for your expert advice, i would never gone that step without this forum.