L322 5.0 Supercharged Wierd problem please Help!!

I have a V8 supercharged and have had it for a few years and everything has been fine. The vehicle had an accident where someone decided to drive into the rear end, it could be a coincidence but shortly after I have a problem in the mornings on a cold start.

If you start the car from cold and don't touch the accelerator the engine will misfire and go into reduced power mode and run real rough, however if you push the accelerator to the floor and go through the rev range you get a little splutter then the car runs all day perfectly until the next morning.

The EML light is on but if you reset it it don't normally come back on for a day or 2.

Codes, apart from the usual the only engine related faults are P0088-00 Fuel rail/system pressure - too high.
I have changed the high pressure sensor on the fuel rail but has made no difference. The high pressure fuel pressure is showing at 11970 Pa and 2.3v

I'm hoping it has not slipped the pump timing chain so does any of you experts have any ideas/experience of the above.

Look forward to your help

Firstly I have no experience of the SC there are a few here but don't think the 5.0l. What is the fuel pressure supposed to be in idle condition? would probably be a good thing to know first.

Here's a link to a vid that may throw some light on it ( i didn't watch it all).

https://us.autologic.com/news/land-rover-5-0-high-pressure-fuel-system

Fuel pressure regulator sticky/blocked?

@Tricky of York , @myfirstl322 any more words of confusion/help

Good luck.

J

marjon said:

@myfirstl322 any more words of confusion/help

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No idea other than the bump may have un-settled sediment in the fuel tank?

myfirstl322 said:

No idea other than the bump may have un-settled sediment in the fuel tank?

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Didn't you have a SUPERCHARGED ? But not a 5 ltr.

tomcat59alan said:

Didn't you have a SUPERCHARGED ? But not a 5 ltr.

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Why yes, yes I did, alas only the 4.2 ....unsurprisingly it also had a fuel tank.

@Tricky of York , @myfirstl322 any morewords of confusion/help

Hi, yes I’ve had two but let’s not get into what stopped the first engine from running.
It is also possible that the bump had triggered a fuel cut off signal but I would have thought that would be effective at the time of the bump. You mentioned in the original post other fault codes, have you looked into all of these back to the accident date?
Another thought is fuel tank / pump / relay electrical connections may have been knocked causing a skip in delivery to the injectors. Again would expect a code for that but still check them.
If your fuel level was low at the time or since the effect is to hiccup delivery to the injectors, something I have experienced that allows you to restart after a wait so worth ensuring no air in the system.
Let us know how you get on please.
Tricky.

myfirstl322 said:

Why yes, yes I did, alas only the 4.2 ....unsurprisingly it also had a fuel tank.

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And a rather large one but not as big as the 5ltr I'd wager.

tomcat59alan said:

And a rather large one but not as big as the 5ltr I'd wager.

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Exactly the same size, but I got an extra 5 minutes of run time at full bore.

myfirstl322 said:

Exactly the same size, but I got an extra 5 minutes of run time at full bore.

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More to the point,did you ever fill it?

High rail pressure could also be a sticking closed or reduced injector performance. Try some good injector cleaner as it it'll be cheaper than swapping injectors out. The injectors have two sides and the ecu doesn't see the physical problem in a sticking or stuck injector unless the solenoid gives an issue.

tomcat59alan said:

More to the point,did you ever fill it?

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Nope...

I've had my SC for 18 months and filled it twice, the main problem with a full tank is it costs over £120 and just delays the inevitable visit to a petrol station.
Tricky.

From what I can recall on the 4.2 and 5.0 the fuel rail has a pressure sending unit that measures the pressure

the fuel pump adjust its speed to get the fuel pressure in the correct range it could also be the regulator either of which can cause the code you're getting, best way to check is by connecting up a fuel pressure gauge to the vehicle and then placing the ignition key in the run position. If the engine is running, you should see a steady 30-40 psi If the motor is not running, then you should be up in the 40-50 psi range.

If the pump is failing which is another possibility it's tend to splutter and fail at higher RPMs.

Henry_b said:

From what I can recall on the 4.2 and 5.0 the fuel rail has a pressure sending unit that measures the pressure

the fuel pump adjust its speed to get the fuel pressure in the correct range it could also be the regulator either of which can cause the code you're getting, best way to check is by connecting up a fuel pressure gauge to the vehicle and then placing the ignition key in the run position. If the engine is running, you should see a steady 30-40 psi If the motor is not running, then you should be up in the 40-50 psi range.

If the pump is failing which is another possibility it's tend to splutter and fail at higher RPMs.

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Hi Henry, the vehicle runs perfect all day after the initial boot in the morning, it is the same every day without fail.

paul