Hello folks, got another issue with the ‘07 Super V8. As soon as I start the car I get a rough idle which continues throughout the rev range. I was only getting fault code for cyl 3 misfire and random misfire. I had just changed the spark plugs two weeks before I started having issues. I changed the cyl 3 coil with one from my donor car and nothing changed so I swapped the cyl 3 coil with one right beside it, no change fault code, still indicating cyl 3. I got 3 more coils from donor car and installed them on passenger side bank of engine, same codes. I swapped old spark plugs back in passenger side bank and no change. Started getting fuel pressure too low code so swapped fuel pressure sensor, still indicating too low along with misfire so swapped throttle body, still misfiring. Checked intake pipe from filter box to throttle body for leaks, no leaks. So I connected scan tool to car and was monitoring fuel pressure at idle which was 36 psi at idle, revved up to 3k rpm and fuel pressure went to about 38 psi then released throttle and fuel pressure dropped to 10 psi, engine stumbles to 500 rpm, and dies. Did this a few times and it died the same way every time.

 

Your fuel pressures are too low even for the "NA" engine. Even TBI injection has minimum pressure needs. Pressures are also erratic when they should not be.

In-tank pump is electrically driven, should come up into the 50 PSIG + range even before the motor first cranks, and not drop at idle. 'Sometimes''.. it is damaged wiring.. but the pumps do NOT "last forever", either.

ISTR the SC models use TWO pumps, but regardless... the process of swapping-in new is well-covered, videos and all.

Renewing the pressure sensors at the same time and checking your evap system is wise. Those parts get old and can go cranky, too.

 

Thanks Thermite, so I checked all of the fuel pump related fuses and all good. I started to salvage the fuel pumps off my donor car and discovered that this car only has one fuel pump on the passenger side, the other side was just a fuel level sending unit. The donor car is also a Super V8 but an 06’ model. I was under the impression that the supercharged cars had two pumps also. Haven’t taken the 07’ apart yet. So which sensor/sensors could be the problem? Could it be the fuel pressure sensor?

 

One HEALTHY fuel pump produces about double the pressures you reported - 50 PSIG or thereabouts. It's a documented pressure range, and not dependent on motor speed. Supercharged verson didn't always have nor 'really' need two ...unless the driver is terminally addicted to 11/10ths rude behaviour that most roads are too crowded for, long-since.

Single or twin, I would NOT depend on salvaging of used pumps, extended off-side pickup rigs (that's not JUST a "sender") related plumbing, filters, tubing, connectors, nor anything else made of plastic! Plastics, no matter how well chosen, "age".

The work to get them out, and put back in shouldn't be wasted on taking the gamble on having to do it all over again with new parts after the stress of manipulating all parts of it out and back worsens any weakened bits.

Worn out or still working, there is too great a safety risk if there is a leak from a crack in the aged plastics - as caused a massive NTSB recall on the Rover's similar, but not identical system.

New goods for the Rover were not terribly costly if one but "shops around" for sharper pricing than dealership and their "tier one" suppliers. Mine were OEM grade from the Chechia factory of VDO division of Continental.

Same source should get your Jaguar's needfuls -single or dual - without having to live on dry beans for the rest of the summer... or at least not ALL of the year?

Chasing a hard-starting issue when warm, I also replaced the Crankshaft Position Sensor on principle, underbody fuel filter, and the fuel system's pressure sensor - none of whom were yet whining for more porridge, plus an evap recovery system solenoid valve that might be telling lies to conceal its declining health but was not going to start getting younger rather than older....

...2005 was "a while ago", 105K plus miles are in the rear-view mirror with whom-knew what had been comng into the tank with the alleged gasolines, nothing on the car is still "new" but for the next "gotcha" trick it may play on my budget and aging ****.

I'm trying to stay a step ahead of its "surprise party" department's warped sense of humour as to what it considers "fun and games" so the jack-up and get-under work is not at the year's worst of nasty weather, let alone a costly flatbed ride distant from home and tools.

You'd guess that the X350 family & cousins of Aluminium Jaguars seem to have a soul?

OUR job is to intercept the sale of that soul to the Devil and subsequent recyling as Aluminium beer cans for long enough to salvage a ration of enjoyable driving!

Nobody said that would be "free", let alone "easy"... but with durable aluminium carcass vs yet-another doomed-to-rusticles steel-bodied GMC .... or worse, MOPAR soccer-Mom van that never even MAKE it to Hell's gates before expiring as Oxides of Iron?

It is surely WORTH the ride!

 

I remember that Jaguar did indeed change the fuel pump configuration on the supercharged versions from two pumps to only one, but I cannot say precisely when this happened.

It might be that it occurred exactly between the two cars you own.

Best regards,

Thomas

 

AFAIK, the whole shebang, remote pickup/'jet' pump extension and float or "bi" pumps and their plumbing CAN be converted the opposite directions, either way - so that might save a few bob on a new one to go with the single + "jet" off-side pickup?

..unless you have to sub for the no-longer-present landing gear on a returning U2 spy plane - a US Government-mandated drag racing exercise for a USAF Major and an Air-force-blue El Camino SS-396 pickerup truck as was a tire-smokin' stitch to watch!

First.. on radioed command... you have to CATCH the aircraft approaching from behind you... from a cold start. The El Camino. Not the U2.

But I would JUST NOT trust old plastic parts of either sexual persuasion in a pressurized fuel application hung under yer passenger's **** and near hot 'sauce pipes.

I kept the Rover's cracked plastics as had begun spraying raw fuel under the vehicle, disaster only delayed by a heat-shield and the Pure Boolshite Luck of some Irish ancestry as a reminder, didn't even ask JLR to compensate parts for my DIY'ing the recall.

Figured at the mileage it had seen, it didn't OWE me a dime, and I had ceased to be "fireproof" when I left Vietnam.

Some savings of coin are not worth risk of dying for, more especially if the savings were meant for yer old age!

 

Thanks guys, so what we are saying here is that my pump is running at half pressure due to wear/old age? I can understand that but the dropping to 10 psi is what I don’t understand, doesn’t there have to be something telling the pump to do that? It just looks like there is something controlling the pump that’s not working and not the pump itself, right? I mean as long as I hold the throttle at 3k the engine will stay at 3k and the pressure remains at 38psi then when I let off the throttle the rpm’s drop and pressure drops to 10psi

 

"Immortal" they were never. A leak doesn't lessen with RPM, either. Your alternator shot and batery flat so the voltage is down below 6 Volts? Hard to miss if that were the case!

A pair of all-metal "High Pressure" fuel pumps - engine cam driven, hence variable speed - on the later model 5.0 "GDI" AJ133 can deliver over 2000 PSIG to the rails.

And fall on their expensive noses if the electrically driven plastic pump back in the tank starves them.

Wear, old age, crap in the lines. CRACK in the lines, damaged wiring.. has to come out, to find out, regardless, and waste of time NOT putting in new for another trouble-free 100K miles.

THEN if you still have a problem, that part is rock-solid as well as safely future-proofed.

Some things are not worth frugalizing yerself over. Stuff as can burn, and burn other stuff, is high on MY list, but the more daring have rebult the in-tank pump with new motors and even rebuilt melted connectors that had melted while immersed in gasoline or its fumes.

A "fuel-air landmine" isn't much different, and those were pee-bringers in a Combat Zone. A similar technique can clear more conventional landmines. Point being that gasoline contains more energy per unit of mass than TNT if only it can get to Oxygen - or a Halogen - one way or another.

Anything WRONG with the system to manage it safely needs fixed, and sooner, not later.