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1998 discovery series 1 v8...throttle body...what fuel pump pressure
Firstly, where are you?1998 discovery series 1 v8...throttle body...what fuel pump pressure
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.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.
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 PSITrue 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.
Your flat wrong my friend.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
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.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
http://users.erols.com/srweiss/tableifc.htmI 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.
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.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.
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.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
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.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>.....
""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.
""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.
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."
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
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Carl Winterbauer <[email protected]>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.
I think you need a new calculator.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
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.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.