FSE rising rate FPR

[4.6_crossbolt]

My EFI SD1, which is slightly tweaked, has an FSE rising rate fuel pressure regulator as advised many moons ago by Mark Adams.

According to the manuals I've read, including Ramon Alban's masterpiece, the pressure in the system should not fall rapidly once the engine is stopped, but gradually over a period of time.

Mine does fall rapidly and testing the system shows that the 'fault' lies in the FPR. I've had it apart and can't see anything obviously wrong. The car doesn't exhibit any significant running problems.

My question is: should it behave in the same manner as an ordinary non-adjustable FPR (i.e. slow pressure fall), or is this a feature of the FSE RR FPR and nothing to worry about?

[kokkolanpoika]

It is common problem with FSE regulators.. My old do just same and couple of friends has also got problems.. They are totally crap

If you want a good one. You have to buy bosch or modify your original like i do..

Adjustable Regulator Kits: I think Marko will ship worldwide?
http://www.finjector.com/verkkokauppa/client/index/25/

Or hole regulator:
http://www.finjector.com/verkkokauppa/client/index/22/

I don´t know if you have got there some supplier who sell same parts.?

[Eliot]

Surely this just means the one-way valve is missing (or faulty). This valve keeps the pressure up in the rails when its not running.
When you first turn the ignition on the pump will run to bring the pressure up and as long as the pump is running when cranking you wont experience a problem.
Sure the FSE regulators are not the best - but there's no need to replace it just because your rail pressure drops to zero when its not running.

My Dakar hasn't had one since i converted to EFI donkeys years ago.

Also - if you change the regulator, you may need to get the car remapped - or more likely the new adjustable FPR adjusted to achieve the same fueling as the existing one. So leave alone unless its causing you a specific problem.

[Baracus]

Yep they are utter shite, bad design and build.

I fitted a weber adjustable non -rising rate and had no problems

[stevieturbo]

I used a few of them on various cars over the last 15 years or more. Cant say Ive ever had a problem.

Whether your pressure drop off is down to the regulator or pump....do you even know ?

Either way, as long as fuel pressure is doing what it is expected to do, I dont see a problem.
Certainly pressure dropping off after shutdown is not a problem as far as I am concerned. Whether some cars dont do it or not is irrelevant really.

[4.6_crossbolt]

...When you first turn the ignition on the pump will run to bring the pressure up and as long as the pump is running when cranking you wont experience a problem.

Mine is still using the flapper system so, in fact, the pump doesn't start until the engine is cranking and the flap has opened a certain amount (about 5 degrees, I believe).

...My Dakar hasn't had one since i converted to EFI donkeys years ago.

Just to satisfy my curiousity, how do you control fuel pressure without a regulator?

...Also - if you change the regulator, you may need to get the car remapped - or more likely the new adjustable FPR adjusted to achieve the same fueling as the existing one. So leave alone unless its causing you a specific problem.

Thanks for the response - I'm coming to the conclusion that maintaining pressure in the rail when stopped is more for the convenience of starting, so that you don't have to crank for too long to build up pressure, rather than any benefit when actually running. I have an uprated pump which takes almost no time to build up pressure, even when the gauge is showing zero pressure before turning the key.

It seems the FSE unit is not very highly regarded, though.

[4.6_crossbolt]

Whether your pressure drop off is down to the regulator or pump....do you even know ?

Yes, because I've been through the test procedure, clamping off the various fuel lines.

Either way, as long as fuel pressure is doing what it is expected to do, I dont see a problem.

I agree

Certainly pressure dropping off after shutdown is not a problem as far as I am concerned. Whether some cars dont do it or not is irrelevant really.

Yes, that's the conclusion I've come to - I was just wondering if anyone else had noticed this phenomonen and whether it was common to the FSE unit.

[r2d2hp]

Can I ask what is meant by rising rate? Thought they were used on Turbo/supercharged engine so the pressure across the injector is kept constant when on boost.

Am surprised Mark recommended a rising rate unless it’s because your ECU is non-adjustable. He did not recommend and changes to the reg when setting up my 14CUX fitted with Tornado chip.

[Eliot]

...My Dakar hasn't had one since i converted to EFI donkeys years ago.

Just to satisfy my curiousity, how do you control fuel pressure without a regulator?

I'm talking about a non return valve not a fpr. I run a bosch 044 and the valve attaches to the outlet of the pump, but that wasn't lifted from the WRC car at the same time the pump was..

[stevieturbo]

Can I ask what is meant by rising rate? Thought they were used on Turbo/supercharged engine so the pressure across the injector is kept constant when on boost.

Am surprised Mark recommended a rising rate unless it’s because your ECU is non-adjustable. He did not recommend and changes to the reg when setting up my 14CUX fitted with Tornado chip.

I think the term they use is rather misleading.

Some literature they post claim it simply responds faster, some say that pressure will rise at a different ratio than 1:1

Either way it is only a small change. Whether or not your engine actually needs extra fuel though is another matter. In general I dont see the point other than the fact it is adjustable which will at least give you some adjustment over mixtures, albeit a crude one.

[4.6_crossbolt]

Am surprised Mark recommended a rising rate unless it’s because your ECU is non-adjustable. He did not recommend any changes to the reg when setting up my 14CUX fitted with Tornado chip.

At the time, which is now about 18 years ago, I was using one of Mark Adams' Tornado non-adjustable ECU's and he recommended (and supplied) the FSE unit. Since then, the engine has grown a bit in cubic capacity, acquired a few more modifications, including an EVO III adjustable ECU, so the Rising Rate FPR may well be superfluous.

So far, the car has never been on a rolling road, and this is something I would really like to do and have Mark set it up properly. Maybe one day, however, I can confirm that it goes very well, has surprised one or two other drivers of modern machinery, and returns about 24 mpg, which I think is a fair indication that the fuelling is not too far adrift.

[4.6_crossbolt]

Some literature they post claim it simply responds faster, some say that pressure will rise at a different ratio than 1:1

Either way it is only a small change. Whether or not your engine actually needs extra fuel though is another matter. In general I dont see the point other than the fact it is adjustable which will at least give you some adjustment over mixtures, albeit a crude one.

As I understand it, the pressure does indeed rise above a 1:1 ratio, to provide extra fuelling when required, i.e. throttle opening.

The FSE unit, I think, is rated at 1:1.7, which is getting on for two to one, so not insignificant. There are some on the market rated at 1:3. Wow! Might well be essential for forced induction.

[DaveEFI]

I had an FSE on my otherwise standard SD1 EFI, and it did improve the running slightly as they tend to run weak. However, if you're using a re-mapped ECU, I can't really see the point - unless that mapping specifically is done round one.

[ramon alban]

According to the manuals I've read, including Ramon Alban's masterpiece, the pressure in the system should not fall rapidly once the engine is stopped, but gradually over a period of time .........

Mine does fall rapidly and testing the system shows that the 'fault' lies in the FPR ...........

Hello ??,

I'm assuming that your test process was similar to this:

Testing the Fuel Pressure Regulator

• Remove the air filter from the airflow meter, switch on the ignition and operate the flap in the air flow meter by hand to energise the fuel pump.
..o The fuel pressure should be 35 - 37 psi

• Switch off the ignition.
..o The fuel pressure should remain at 35 - 37 psi

• The fuel pressure may fall very slowly due to inconsequential weeping in either the fuel pressure regulator valve or the fuel pump non-return valve.
..o A slow steady fall is acceptable but a rapid fall must be investigated

• If the pressure test is unsatisfactory the most likely cause of the problem is the fuel pressure regulator.
..o Replace the fuel pressure regulator with a new or known good substitute unit

• If after fitting a known good regulator and re-testing the system, the pressure continues to fall rapidly check the following until the cause is found.
..o The fuel injectors
..o The fuel pump non-return valve
..o The fuel system pipe-work

• Depressurise the fuel system again before removing the test gauge.

• After final reconnection of the pipes check for fuel leaks at all the joints both before and after the fuel injection system is re-pressurised.

You'll see that I have highlighted some sections to emphasise my observations.

1 the pressure on your non standard Efi system may have been set to something other than 35 37 psi but the rest of the process is valid.

2 unless you somehow isolated the FPR, how can you be sure it is not faulty?

3 the injectors, fuel pump and pipework can all be equally suspicious for losing pressure, after the ignition is switched off.

My question is: should it behave in the same manner as an ordinary non-adjustable FPR (i.e. slow pressure fall), or is this a feature of the FSE RR FPR and nothing to worry about?

In my opinion, pressure should not decline as rapidly as you have observed but it would not stop the system from working.

Moving on, there are clearly some valid reasons for fitting either an adjustable or Rising Rate FPR, which can change the fueling across the board or provide a boost when needed under full load, respectively.

However if your system is running at 35-37 psi and you have an ECU that has acceleration and full load enrichment circuits then the reason for fitting an additional boost, by RR FPR, is somewhat negated.

If the rapid pressure drop (when ignition is switched off) is a genuine feature of your particular FRP then, as stevieturbo says, may not adversely affect the system when running, because as soon as the fuel pump engages, the pressure build up will fire up the engine with only a short delay.

HOWEVER, if a fault is elsewhere then you can be sure it will not be self-healing and you will/may eventually get a total failure - so probably best to eliminate the problem before you get stranded.

[stevieturbo]

Some literature they post claim it simply responds faster, some say that pressure will rise at a different ratio than 1:1

Either way it is only a small change. Whether or not your engine actually needs extra fuel though is another matter. In general I dont see the point other than the fact it is adjustable which will at least give you some adjustment over mixtures, albeit a crude one.

As I understand it, the pressure does indeed rise above a 1:1 ratio, to provide extra fuelling when required, i.e. throttle opening.

The FSE unit, I think, is rated at 1:1.7, which is getting on for two to one, so not insignificant. There are some on the market rated at 1:3. Wow! Might well be essential for forced induction.

TBH, rates like that are absolutely the last thing you'd want with boost. That's why I dont believe even the 1:1.7 is correct.

No OEM fuel pump will ever cope or maintain any flow worth talking about at the pressures you would ask them to achieve.

The likes of the very high ratios you mention, they class them as "Fuel Management Units". A VERY CRUDE botch for a low boost application where no proper fuel tuning will take place.
So instead they just ramp up the fuel pressure in an attempt to maintain safe fuelling.

But say a base pressure of 45psi, 20psi boost and 1.7x, you'd be talking almost 80psi fuel pressure.
Most OEM pumps would be pooing their pants around 60-70psi. Even the mighty little Walbro starts to fall flat o its face around 75-80psi.

that's why I simply dont believe they increase fuel pressure by that ratio, although must admit have never tested one.