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1998 discovery series 1 v8...throttle body...what fuel pump pressure
Firstly, where are you?
In 1998 the motors were completely different in the USA compared to the rest of the world.

Fuel pressure with no vacuum to the fuel pressure regulator should be 2.5 bar or around 36 psi.
 

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Firstly, where are you?
In 1998 the motors were completely different in the USA compared to the rest of the world.

Fuel pressure with no vacuum to the fuel pressure regulator should be 2.5 bar or around 36 psi.
True but the LR regulators old or new I have tested resulted in pressure readings that were near the minimum spec range of the LR Factory Shop manual specs.
Depending on the year and model like my 95 D1 w/2002 4.6, GEMS with distributor as example. Installed a BMW 3.0 regulator which fit perfectly now providing fuel pressure at the upper maximum range allowing for better injector fuel flow streams. Must add I replaced the single dribble Lucas injectors of 80's design with Bosch 4 hole injectors with a narrow 15* fan spray pattern. Finer spray pattern one fourth the diameter of Lucas's single dribble injectors times four.
A vast improvement in overall running plus now instant starts hot or cold by the second cylinder having a complete compression cycle. Usually the first cylinder over compression hasn't the chance for a complete compression cycle as it might of stopped part way up the compression stroke last time the crank stopped rotation.
Rocking the D1 body in 2nd gear (i'm a 5 speed) enough to jar the crank rotating it enough to for the next cylinder on compression it will fire up, shudder then lug away until it reaches its normal idle rpm's. It NEVER started that quickly with OEM Lucas injectors. Trouble free happy miles going on seven years and counting. :nerd
 

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True but the LR regulators old or new I have tested resulted in pressure readings that were near the minimum spec range of the LR Factory Shop manual specs.
Depending on the year and model like my 95 D1 w/2002 4.6, GEMS with distributor as example. Installed a BMW 3.0 regulator which fit perfectly now providing fuel pressure at the upper maximum range allowing for better injector fuel flow streams. Must add I replaced the single dribble Lucas injectors of 80's design with Bosch 4 hole injectors with a narrow 15* fan spray pattern. Finer spray pattern one fourth the diameter of Lucas's single dribble injectors times four.
A vast improvement in overall running plus now instant starts hot or cold by the second cylinder having a complete compression cycle.
The reason that you will be getting better cold starts will be that you are now over fueling the motor. Just a couple of PSI can make a huge difference in the amount of fuel getting into the motor and you just increased it by 7 PSI
 

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The reason that you will be getting better cold starts will be that you are now over fueling the motor. Just a couple of PSI can make a huge difference in the amount of fuel getting into the motor and you just increased it by 7 PSI
Your flat wrong my friend.
Second reply, took too long last reply, lost it all. Second try a short version as Thanksgiving dinner here in the USA.
The computer receives signals from the Mass meter, fuel rail, air inlet temp under open loop (cold start conditions) which are rough guidelines vs tight guidelines during closed loop with the O2 sensors awake and operating. EPA in the US would not allow a fixed rich cold start without control of the different air temps and climates.
The computer controls the injector pulse width within the minimum to maximum fuel rail pressures noted in the Rover Workshop Manual.
My cold start open loop fueling ratios are darn near the same with the 3.0 regulator and Bosch 4 hole injectors vs reinstalling the old Lucas single squirt injectors.
Only differences the 4 hole injectors fired right up, back to Lucas install required several cylinders over compression to fire up be it a cold or a hot engine.
I read 41.3 psi fuel rail pressure, less psi increase above the max psi in the Shop Manual than the manual's low to high psi limits which I found to be already below minimum spec with used 2.5 bar and even with a new one still near the minimum psi of the Workshop Manual specs.
Even testing on an old EPA 75 (two gas ) machine the fuel ratios were darn near the same at cold start with the hot running the 4 hole injectors having lower HC number readings. I can't knock the 2.3 mpg fuel mileage increase as well overall running conditions replacing 1980's injectors with 2000 era upgrades as well better injector streams being smaller backed up with higher pressures. Letting the computer pulse width control handle the fuel ratios. PROST.....~~=o&o>......:grin
 

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Your flat wrong my friend.
Second reply, took too long last reply, lost it all. Second try a short version as Thanksgiving dinner here in the USA.
The computer receives signals from the Mass meter, fuel rail, air inlet temp under open loop (cold start conditions) which are rough guidelines vs tight guidelines during closed loop with the O2 sensors awake and operating. EPA in the US would not allow a fixed rich cold start without control of the different air temps and climates.
The computer controls the injector pulse width within the minimum to maximum fuel rail pressures noted in the Rover Workshop Manual.
My cold start open loop fueling ratios are darn near the same with the 3.0 regulator and Bosch 4 hole injectors vs reinstalling the old Lucas single squirt injectors.
Only differences the 4 hole injectors fired right up, back to Lucas install required several cylinders over compression to fire up be it a cold or a hot engine.
I read 41.3 psi fuel rail pressure, less psi increase above the max psi in the Shop Manual than the manual's low to high psi limits which I found to be already below minimum spec with used 2.5 bar and even with a new one still near the minimum psi of the Workshop Manual specs.
Even testing on an old EPA 75 (two gas ) machine the fuel ratios were darn near the same at cold start with the hot running the 4 hole injectors having lower HC number readings. I can't knock the 2.3 mpg fuel mileage increase as well overall running conditions replacing 1980's injectors with 2000 era upgrades as well better injector streams being smaller backed up with higher pressures. Letting the computer pulse width control handle the fuel ratios. PROST.....~~=o&o>......:grin
Firstly, the fuel pressure changes only relate to the vacuum in the intake system. When there is high vacuum the intake is trying to suck the fuel out of the injectors and therefore the fuel pressure is drop. With little or no vacuum the fuel pressure is increased. That is why the fuel pressure regulator is controlled by intake vacuum.
I have bosch 4 hole injectors as well. They have the exact same flow rate as the standard lucas injectors. So they have no effect on the amount of fuel released or what pressure is ran.
Finally, the closed loop system tends to only work at cruise and moderate acceleration. As you have already agreed, it has no affect at start up, idle or wide open throttle. My comment that you have taken objection to related to cold starts.
 

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I have bosch 4 hole injectors as well. They have the exact same flow rate as the standard lucas injectors. So they have no effect on the amount of fuel released or what pressure is ran.
Finally, the closed loop system tends to only work at cruise and moderate acceleration. As you have already agreed, it has no affect at start up, idle or wide open throttle. My comment that you have taken objection to related to cold starts.
http://users.erols.com/srweiss/tableifc.htm
With running at 3.0 bar vs Rover's 2.5 bar regulator the 4 hole Bosch (Ford letters also on the Bosch injectors) now have a higher pounds/hour injector flow numbers. You can push an injector's inlet pressure a lot higher than the pressure (vacuum) swings you mentioned between idle and vs heavy or 3/4 throttle. You would have to run a boosted intake pressure, supercharger or turbo before the manifold pressure would effect the injectors. No way on these NA engines.
The 4-hole injectors i'm running can feed up to a 5.8 litre (351 cu/in) Ford engine on down to 4.0 litre engines.
I fully agree on your replies with closed loop operation conditions except your open loop fueling control.
I know you Ozzies are crazy gear heads into engines and racing about as bad as us Yanks in the U.S.A.
David Grubnic comes to mind as a NHRA Top Fuel racing owner of a dragster. I have personally talked with "Grubbie" at a NHRA meet and track app 38 miles from home. I'm into Pro Stock cars and bikes, not Top Fuel a big money TV Hype thing. Formula One's high tech and Pro Stock cars vs Nitro BS.
I must mention the vacuum advance on the 95 D1 is total crap failing by 19 months on average plus reduced advance degrees for the California market.
Here in California the vacuum advance is limited in degrees advance, not as much as a D1 sold in the other 49 states.
Gaining more degrees advance yet than than even the 49 state advance units are those rebuilt "Down Under". I purchased one.
They in Oz use a higher quality diaphragm material vs LR's expensive POS units. I'm at 16 years and counting without the vacuum advance unit failing. Way cheaper also vs LR's price.
Sorry if I mixed the word "GEMS" engine as the 2002 4.6 has all the 3.9's accessories down to a distributor vs later D1's with coil packs being called "GEMS" I recall. There's several reasons why I own a OBD1 Disco. Also running a Mark Adams "Tornado" chip with Magnaflow's high flow cats (94305 numbers) that have straight inlets and outlets a 2 1/4" nipple stub vs other manufactures with a common inlet stub restriction no matter the inlet and outlet advertised stub sizes offered. Yup an instant restriction problem like Borla's cat back exhaust I run in stainless. Early production had an "hourglass" pipe slide into the inlet of the muffler reducing the inlet cross sectional area to 50% of the 2 1/4" inlet pipe ID. Grind the pipe stub end weld removing this restriction an instant quick fix with better flowing muffler.
It took a dump rattling internally a "Lifetime million mile muffler". Yeah right, spent almost 5 months arguing with Dave Borla, told "you found the muffler in wrecking yard". Yeah right with warranty card, told "you printed up a hundred of them". Dave Borla's dad answered the phone, I emailed my credit card record with performance shop billing, paid for a second muffler with credit back once they received their defective muffler. Word of wise, keep all paperwork dealing with any Borla exhaust purchases.
Later production stainless cat back mufflers eliminated this restriction.
PROST.....~~=o&o>......:smile
 

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Stan Weiss' - Electronic Fuel Injector (EFI) Flow Data Table
With running at 3.0 bar vs Rover's 2.5 bar regulator the 4 hole Bosch (Ford letters also on the Bosch injectors) now have a higher pounds/hour injector flow numbers. You can push an injector's inlet pressure a lot higher than the pressure (vacuum) swings you mentioned between idle and vs heavy or 3/4 throttle. You would have to run a boosted intake pressure, supercharger or turbo before the manifold pressure would effect the injectors. No way on these NA engines.
I am not sure what you are debating. You agree in your first sentence that it will now have a higher flow rate. That is, it is putting in more fuel than it use to.
A fuel pressure regulator for a turbo or supercharged motor will increase the fuel pressure even more as the pressure in the intake increases.
The amount of fuel being put into the motor is controlled by how long the injector is held open, not the fuel pressure. The changes in fuel pressure only relates the the manifold vacuum/pressure.

Try reading about "effective pressure" here http://injectordynamics.com/articles/fuel-pressure-explained/
 

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I am not sure what you are debating. You agree in your first sentence that it will now have a higher flow rate. That is, it is putting in more fuel than it use to.
A fuel pressure regulator for a turbo or supercharged motor will increase the fuel pressure even more as the pressure in the intake increases.
The amount of fuel being put into the motor is controlled by how long the injector is held open, not the fuel pressure. The changes in fuel pressure only relates the the manifold vacuum/pressure.

Try reading about "effective pressure" here Fuel Pressure Explained - Injector Dynamics
With a given injector like as example an 18 lbs/ hr injector fueling an engine properly but narrowing the safety margin down at 95% duty cycle and a possible lean out vs an ideal max of 80% duty cycle at high rpm's with an elevated psi regulated rail pressure.
This allowing for a wider safety margin vs replacing injectors of a higher lbs/hr rating.
Elevated pressure also helps in providing a finer injector spray mist pattern vs an injector operating at an minimum operating injector pressure spec.
Yes granted duty cycle controls the amount of fuel injected for a proper F/A ratio but add an elevated injector pressure letting the computer compensate by shortening the duty cycle also increases the safety margin to 20% reserve duty cycle vs only 5% in the above example numbers. I'll take a higher applied pressure injector of lower lbs/ hr providing a finer spray and mist than a larger injector operating at the minimum or below minimum spec dribble I encountered working on my LR fueling project.
Heck 2:37 AM past bed time here in California. Catch ya later mate......~~=o&o>.....
 

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With a given injector like as example an 18 lbs/ hr injector fueling an engine properly but narrowing the safety margin down at 95% duty cycle and a possible lean out vs an ideal max of 80% duty cycle at high rpm's with an elevated psi regulated rail pressure.
This allowing for a wider safety margin vs replacing injectors of a higher lbs/hr rating.
Elevated pressure also helps in providing a finer injector spray mist pattern vs an injector operating at an minimum operating injector pressure spec.
Yes granted duty cycle controls the amount of fuel injected for a proper F/A ratio but add an elevated injector pressure letting the computer compensate by shortening the duty cycle also increases the safety margin to 20% reserve duty cycle vs only 5% in the above example numbers. I'll take a higher applied pressure injector of lower lbs/ hr providing a finer spray and mist than a larger injector operating at the minimum or below minimum spec dribble I encountered working on my LR fueling project.
Heck 2:37 AM past bed time here in California. Catch ya later mate......~~=o&o>.....
You just agreed that the O2 sensor only controls the duty cycle when at cruise and light acceleration. Not wide open throttle, idle, start up etc.
You also fail to acknowledge that your vehicle runs a narrow band O2 sensor that can only report fuel mixtures around cruise. It is not capable of controlling fuel mixtures under power.
If your duty cycle is going to max out it will be under power at high revs. So your computer is not going to change the duty cycle at all because it is not taking any notice of your narrow band O2 sensor in these conditions.
The standard fuel pressure and injectors are more than capable of fueling the motor.
The problem you appear to have is that you are running a 4.6 with a 3.9 fuel system. You could get a 4.6 ECU as the GEMS was also used on the 4.6 motor. By rights changing the motor should not require any changes to the fuel mapping. The 4.6 sucks more air and therefore the standard system will add enough fuel to match. However it does not work out exactly and you need to increase the fuel pressure by around 2 to 3 psi compensate. 7+ PSI is way too much.
How do I know this? I run 2 different vehicles that have 4.6's on 3.9 EFI systems.
I also run a variable fuel pressure regulator that I can adjust as small intervals. I also run a wide band O2 gauge that tells me exactly what my fuel mixture is.
 

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"However it does not work out exactly and you need to increase the fuel pressure by around 2 to 3 psi compensate. 7+ PSI is way too much".
"How do I know this? I run 2 different vehicles that have 4.6's on 3.9 EFI systems.
I also run a variable fuel pressure regulator that I can adjust as small intervals. I also run a wide band O2 gauge that tells me exactly what my fuel mixture is.
"

Is this the adjustable fuel regulator your talking about above? I had to ask.:grin
 

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"However it does not work out exactly and you need to increase the fuel pressure by around 2 to 3 psi compensate. 7+ PSI is way too much".
"How do I know this? I run 2 different vehicles that have 4.6's on 3.9 EFI systems.
I also run a variable fuel pressure regulator that I can adjust as small intervals. I also run a wide band O2 gauge that tells me exactly what my fuel mixture is.
"

Is this the adjustable fuel regulator your talking about above? I had to ask.:grin

https://shop.v8engines.com/adjustable-fuel-pressure-regulator-for-hotwire-efi-system-75-p.asp

To test your old pressure regulator, check your fuel pressure at the rail, then suck on the vacuum hose to check the integrity of the diaphragm.
This is a rising rate pressure regulator which increases fuel pressure at around 1.7x the standard rate under acceleration, boosting power under load
Email and telephone assistance avaialable from RPi if required
We are also able to supply ECU chipping, essential ignition upgrades, ingjectors, carbon triple throttle body inlet plenums and much more. Please enquire.
 

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"

Is this the adjustable fuel regulator your talking about above? I had to ask.:grin

https://shop.v8engines.com/adjustable-fuel-pressure-regulator-for-hotwire-efi-system-75-p.asp

To test your old pressure regulator, check your fuel pressure at the rail, then suck on the vacuum hose to check the integrity of the diaphragm.
This is a rising rate pressure regulator which increases fuel pressure at around 1.7x the standard rate under acceleration, boosting power under load
Email and telephone assistance avaialable from RPi if required
We are also able to supply ECU chipping, essential ignition upgrades, ingjectors, carbon triple throttle body inlet plenums and much more. Please enquire.
I had one of those but found it not that good. It would keep on changing the pressure by itself. You also need a 1:1 (standard for fuel regulators) rather than a 1.7:1. The 1.7:1 made it more difficult to tune over the full power range.
But you do need the fuel rail adaptor in that kit to connect up an aftermarket regulator.
 

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I had one of those but found it not that good. It would keep on changing the pressure by itself. You also need a 1:1 (standard for fuel regulators) rather than a 1.7:1. The 1.7:1 made it more difficult to tune over the full power range.
But you do need the fuel rail adaptor in that kit to connect up an aftermarket regulator.
Carl Winterbauer <[email protected]>
2:19 PM (7 minutes ago)
to landroversonly.com

With all this offered services;https://shop.v8engines.com/sitemap.asp. under Chris Crane's leadership, Rimmer Brothers as well Mark Adams with his "Tornado" chip none of them ever addressed having a problem with installing a 3.0 Bar fuel regulator vs LR's 2.5 Bar offerings.
This makes me think RPI's (Chris Crane's) adjustable regulator they are selling boosting the fuel rail pressure way above the 3.0 Bar regulator (BMW's a direct fit) that i'm running that is too rich at idle and full throttle you mentioned then then the adjustable regulator must be off the charts too rich at cold start and full throttle.
So they, Rimmer Brothers, Mark Adams and Chris Crane with all their research, dyno and road testing never took into account a 3.0 Bar regulator would cause a filthy rich cold start and full throttle condition? I have yet to see these running too rich problems with the 3.0 Bar regulator install.
Mind you I did borrow for a day a friend's INNOVATE F/A gauge with wide band O2 sensor (both used off a EFI small block Chevy) and had reading considered within range at cold start and full throttle "don't worry your safe" with Chris Crane as well a Mark Adams reply. Mark Adams must of done his homewark designing that "Tornado" chip i'm running at over 16 years and counting.
The only times the gained 2.3 mpg increase became below what was gained has been because of driving too aggressively.

Can't help myself with several full throttle runs. While testing I used 2-3 miles long stretches of highway, chop and kill the ignition with results of normal plug readings as well never had any problem with cold starts with sooty carbon buildup or fouled plugs checked at 30 seconds and again at one minute of warm up from a stone cold engine starts.
I did get strange looks driving and testing with a fuel rail gauge, vacuum gauge and lines sprouting out from under the hood with gauges clustered together in a small cardboard box secured an top of the dash.:smile

Oops company arriving, a turbo Subi with a larger turbo and inter cooler transplant. PROST.....~~=o&o>......


Carl Winterbauer <[email protected]>
2:25 PM (1 minute ago)
to me
 

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This makes me think RPI's (Chris Crane's) adjustable regulator they are selling boosting the fuel rail pressure way above the 3.0 Bar regulator (BMW's a direct fit) that i'm running
I think you need a new calculator.

A standard reg runs from 2.0 bar to 2.5 bar. It is only the movement of 0.5 bar that is 1:1. So if you went to 1.7:1 is is 1.7x0.5 bar or 0.85 bar. So it will go between 2.0 and 2.85 instead of 2.0 to 2.5.

How is 2.85 bar way above 3.0.

I am also reasonably sure that the 1.7:1 still does not increase by more than 0.5 Bar, it just gets there sooner.
 

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I think you need a new calculator.

A standard reg runs from 2.0 bar to 2.5 bar. It is only the movement of 0.5 bar that is 1:1. So if you went to 1.7:1 is is 1.7x0.5 bar or 0.85 bar. So it will go between 2.0 and 2.85 instead of 2.0 to 2.5.

How is 2.85 bar way above 3.0.

Must be the "new math"?

I am also reasonably sure that the 1.7:1 still does not increase by more than 0.5 Bar, it just gets there sooner.
The 3.0 bar BMW regulator I keep mentioning should have a conversion of 43.51 psi when using 1 bar conversion equals 14.5038 psi. I recorded a bypass at 41.30 psi which I mentioned in my above reply.
Your 2.85 bar conversion to psi equates to 41.33583 psi using 1 bar equals 14.5038 psi conversion math.
This means the 41.30 regulator i'm running is slightly lower than the 2.85 bar of 41.33583 psi by 0.03583 psi or 0.00247 bar below which is 2.847 bar vs 2.85 bar maximum.
I can or my engine can live with any slight A/F ratio difference at cold start and full throttle running leaner on the oxygenated pump gas we must use.
I believe these above slight differences in pressures in bars are way below production tolerances of pressure regulators, a new 3.0 spec regulator having 2.847 bar real world bypass as example.
I'm in favor of rich before lean not seeing aluminum coming out of the tailpipes or open headers. :grin....~~=o&o>.....
 

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The basic fact is that 0.5 bar is 7.25 psi higher than the motor requires.
This means that the motor will run richer at all times except when the O2 sensor is active at cruise.
All you appear to want to debate is how much richer it will run.
Based on all the different settings I have tried on my adjustable fuel regulator, it will be running a lot richer.
 
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