fuel pump pressures

[nowoolies]

i am just about to get a chip fitted to the bus
and i have had a bit of a chat with the bloke about mileage as mine is crap, 5.48 klm per ltr on average
i am told i can expect a big change if i get the fuel rack pressue bought up to speed, as this is a common problem with the common rail on the patrol.
nissan wont acknowledge it as a problem, (typical).
he sell`s the chip and has a fair understanding on them and on milage.
apparently i can expect a fair change in my mileage with the chip , and after proving this i am to remove it , take the bus to nissan and get my fuel pressures bought up to speed , i am told if the fuel pressure is low i can expect crap fuel economy.
has anyone else heard of this
thanks
nowoolies

[Maxhead]

Hmmm, that's interesting. Wouldn't surprise me though.

Not sure where I heard it but Chip-It performance chips will also increase rail pressure or ask you to increase it when fitting their chips...not sure if this is correct or not


Which chip are you looking at?

[Maxhead]

This is from another forum where a guy did a trial on the chip it chip.


Chip It - Fuel Rail Pressure Relief Valve Modification

The fuel rail pressure relief modification is the ultimate modification recommended by Chip It and allows one to explore the highest levels of tunes. To get the maximum out of the Chip It requires what I might consider to be a fairly extensive and risky modification to your vehicle. The fuel rail, to which the fuel pressure relief valve is attached, is not a Nissan serviceable part, even though the valve can be removed, so if you damage anything on this rail, you're up for a complete new rail assembly.

The relief valve removal is not overly complex, effectively requiring the removal of a bolt (the fuel pressure relief valve has a hexagonal head), but it's replacement could leave you in a world of hurt trying to get it tight enough again, so that you don't get fuel leaks, and you can't afford fuel leaks when fuel pressures are up around 13,000psi or higher. You also have to exercise great care when the components are taken apart, so as not to introduce any contaminants into the fuel rail etc and you will also have to bleed the fuel system once everything is back together.

The other risk with the fuel rail modification is that if the relief pressure is set too high, then there's a potential for this to cause damage in other areas. Using the fuel rail limiter washer means that the relief pressure is raised to some unknown degree and the blank could potentially allow the fuel pressure to rise to whatever maximum the fuel pump can supply. Now this would only occur at full load, as the vehicle's ECU controls the pressure as required, but it wouldn't stop over-pressurisation, so you need to be aware of this risk.

Every CRD is slightly different in build specification, so there's no way to know to what level this modification would raise the relief pressures. My particular Patrol was able to comfortably go to tune levels that other Patrols apparently could not, without the fuel rail modification, so this already was an indicator that caution needed to be exercised. To that end, I decided discretion was the better part of valour and didn't proceed with this modification.

I'm not saying that one shouldn't attempt this modification, but be very aware of the risks, before you wield that spanner.

[nowoolies]

Hmmm, that's interesting. Wouldn't surprise me though.

Not sure where I heard it but Chip-It performance chips will also increase rail pressure or ask you to increase it when fitting their chips...not sure if this is correct or not


Which chip are you looking at?

thanks mate for the info
i hope thats not part of whats about to happen
the chip is a Tunit chip
have you heard of these ????

[YNOT]

This is from another forum where a guy did a trial on the chip it chip.


Chip It - Fuel Rail Pressure Relief Valve Modification

The fuel rail pressure relief modification is the ultimate modification recommended by Chip It and allows one to explore the highest levels of tunes. To get the maximum out of the Chip It requires what I might consider to be a fairly extensive and risky modification to your vehicle. The fuel rail, to which the fuel pressure relief valve is attached, is not a Nissan serviceable part, even though the valve can be removed, so if you damage anything on this rail, you're up for a complete new rail assembly.

The relief valve removal is not overly complex, effectively requiring the removal of a bolt (the fuel pressure relief valve has a hexagonal head), but it's replacement could leave you in a world of hurt trying to get it tight enough again, so that you don't get fuel leaks, and you can't afford fuel leaks when fuel pressures are up around 13,000psi or higher. You also have to exercise great care when the components are taken apart, so as not to introduce any contaminants into the fuel rail etc and you will also have to bleed the fuel system once everything is back together.

The other risk with the fuel rail modification is that if the relief pressure is set too high, then there's a potential for this to cause damage in other areas. Using the fuel rail limiter washer means that the relief pressure is raised to some unknown degree and the blank could potentially allow the fuel pressure to rise to whatever maximum the fuel pump can supply. Now this would only occur at full load, as the vehicle's ECU controls the pressure as required, but it wouldn't stop over-pressurisation, so you need to be aware of this risk.

Every CRD is slightly different in build specification, so there's no way to know to what level this modification would raise the relief pressures. My particular Patrol was able to comfortably go to tune levels that other Patrols apparently could not, without the fuel rail modification, so this already was an indicator that caution needed to be exercised. To that end, I decided discretion was the better part of valour and didn't proceed with this modification.

I'm not saying that one shouldn't attempt this modification, but be very aware of the risks, before you wield that spanner.

I would advise against touching the rail of a common rail diesel unless you know what you are doing. The pressures inside the rail are EXTREME and can cause serious injury if you don't know what you are doing.

Tony

[Maxhead]

thanks mate for the info
i hope thats not part of whats about to happen
the chip is a Tunit chip
have you heard of these ????

No, I haven't mate but if you go ahead I'd be interested to see how it goes

[nowoolies]

I would advise against touching the rail of a common rail diesel unless you know what you are doing. The pressures inside the rail are EXTREME and can cause serious injury if you don't know what you are doing.

Tony

thanks for that Tony
i have not even thought about touching it myself
but if the pressure is low then i will let nissan sort that out
have you had much to do with chips
the one im just about to go and pick up is a tunit chip same as the dp chip im told

[Maxhead]

I would advise against touching the rail of a common rail diesel unless you know what you are doing. The pressures inside the rail are EXTREME and can cause serious injury if you don't know what you are doing.

Tony

That would be the last thing I'd be doing Tony but looks people are doing it .
If it was a Nissan issue I would be interested to find out what the pressure is supposed to be then get them to test it.

Cheers

[nowoolies]

No, I haven't mate but if you go ahead I'd be interested to see how it goes

i will post before and after results
i have been told not to touch the exhaust as the chips are designed to run the bus at factory spec`s
and that is by two of the sellers

[nowoolies]

well been for the run into town traffic was that heavy hardly could tell the differance , apart from it feels like driving a sports car on take off hahahahahahaha, setting is as i recieved it on 5.
can hardly feel the gear changes, at all now.
power is up and that flamming horrible lousey rotten stinking flat spot ..........................is gone yeeeee haaaaaaaa
and i forgot to change the setting to 6 for the drive home.

went up the farm to see timbo and his family they are camping up there
changed the setting to 6 for this drive hahaha

well couple of big hills to go over, i started at the bottom of the biggest at 100klm and apart from 1 gear change (she`s auto) 3/4 the way up and that was only for a couple of seconds, i did not loose any speed and i had the bus in overdrive and with the cruise control on , the hill is approx 2 .5 klms on the climb, to the top of the steep part and its still up hill for a couple more klm`s on a easy climb the bus did`nt miss a beat

next hill, nearly as big, i tried with the overdrive off and the cruise control off......... strike me sideways i was around 130klm without trying, and this is climbing up hill ,and still accelerating i backed off at 130klm and slowed down to 100klm no gear change, no nothing, sweet as.

i started the day with the needle just on the right side of the half full mark
by the time i got home the round trip is about 120klm for the farm and around 80klm for the trip into town 200klm in all and the needle is just under the half way mark when i got back to home.
well so far, not three bad at all
going back up the farm today with a full car full of the family ,
will post the power results tonight.