Hello

Just been looking through some posts and found a couple of negative threads regards Ron Box’s destroying HP fuel pumps. Googling took my to the Rover 75 forum somewhere…

My question(s) are regards how the pump failed and what damage was caused? I have a bit of a fetish regard diesel pumps and am a little surprised that a purely mechanical pump would fail.

Also has it ever been determined that a HP pump had been worn or had badly deteriorated because of other factors such as water contamination or the use of ‘bio fuel’ or …. Cooking oil..or has it been ascertained that the failure was solely down to the Ron Box.

I had read several reviews more than a few years ago regards Ron Box’s all of which were positive and seemed to confirm the Perfomance and fuel savings/gains etc.

Finally.. (I do go on a bit) have any of these HP pumps been rebuilt after ‘failure’ or is the damage so catastrophic that they are scrapped as a normal course?

Opinions and experiences most welcome…

MollyNomad said:

Hello

Just been looking through some posts and found a couple of negative threads regards Ron Box’s destroying HP fuel pumps. Googling took my to the Rover 75 forum somewhere…

My question(s) are regards how the pump failed and what damage was caused? I have a bit of a fetish regard diesel pumps and am a little surprised that a purely mechanical pump would fail.

Also has it ever been determined that a HP pump had been worn or had badly deteriorated because of other factors such as water contamination or the use of ‘bio fuel’ or …. Cooking oil..or has it been ascertained that the failure was solely down to the Ron Box.

I had read several reviews more than a few years ago regards Ron Box’s all of which were positive and seemed to confirm the Perfomance and fuel savings/gains etc.

Finally.. (I do go on a bit) have any of these HP pumps been rebuilt after ‘failure’ or is the damage so catastrophic that they are scrapped as a normal course?

Opinions and experiences most welcome…

Click to expand...

I know of loads of pumps that leak after the Ron Box (it's actually called a Synergy) was fitted, including 3 of my own even after rebuilding 2 of them.
The issue is down to how the RB increases power on the engine.
What it's actually doing is tricking the ECM to believe the fuel rail pressure is lower than it actually is. This means the ECM increases the rail pressure above pressure it should be, resulting in higher fuel flow from the injectors and so greater power. At the same time is does the same trick to the MAF signal, tricking to the ECM that there is sufficient air available to prevent the smoke mitigation strategy from being implemented.
I can't remember if there a connection to MAP feedback too, but it's possible.

Basically these "fudges" make the engine develop more power, even though the ECM thinks everything is normal.

The pump issue is due to mechanical limitations of the Bosch CP1 pump itself. Basically forcing the ECM to demand more pump pressure is exceeding the pump maximum pressure output specification, which results in the head pressure seals from leaking. I'm unsure as to whether this is a mechanical limit of the pump itself, or the seals, or the bolts that keep the heads clamped to the seals, or maybe a combination of all of those things.

Edit: Typo correction.

So, as a conclusion, you should'nt scratch if not itching (Hope I wrote it correct) and let things as factory made it.
Am I right, or too conservative?

The Pilgrim said:

So, as a conclusion, you should'nt scratch if not itching (Hope I wrote it correct) and let things as factory made it.
Am I right, or too conservative?

Click to expand...

A proper remap is much better at producing power without exceeding the maximum output pressure of the pump, as additional fuel is added through injector pulse lengthening and timing adjustments.

A remap to smooth out the design flaws in the power band without exceeding the original power output and to make the vehicle more driveable seems the best route.

Does anyone have actual rail pressure increase numbers for the synergy box? How over pressure does it go? I’ve got one fitted for the last 60k miles without any problems but don’t fancy doing a hp pump. I do run mine on the lowest setting though.

Difficult to say, as the only way to measure the rail pressure is with the rail sensor signal, which is being augmented by the Synergy, so the reading on live data is false.

I do know the pump has a maximum designed pressure of 1350 Bar, and the ECM limits rail pressure to a maximum of 132,000 kPa which is 30 Bar under the maximum.
So it doesn't take much of a rail pressure increase to push the pump over 1350 Bar maximum designed pressure. I suspect that rust jacking of the pump head plays a part, as the pump does get wet in heavy rain, so rust forms between the pump head and block. However I've also had the Synergy make a rear head seal leak, where there wasn't any rust, so I suspect the pump simply isn't designed to output the pressure a turned up Synergy can ask it to make.

I've proven the concept of leaking too, where a leaking pump on a Synergy has stopped leaking when the Synergy was taken out of circuit, and continued to remain leak free for some months, only to leak again the moment the Synergy was put back in.
Using the Synergy definitely caused issues for me and many others, making a proper remap the best choice on this engine. Don't forget the BMW e46 M47 makes loads more power than the FL1 M47R, and the only difference is injectors, turbo and mapping, all while keeping the pump pressure below the maximum specification.

Nodge68 said:

A proper remap is much better at producing power without exceeding the maximum output pressure of the pump, as additional fuel is added through injector pulse lengthening and timing adjustments.

Click to expand...

Sorry for hi jacking this but I was getting a map done on mine soon
but it’s a absolute fly machine loads of instant power pulls hard loads grunt (My old Freelander was no where near this one regarding power)
my question is how would you definitely know one way or the other if it’s already been mapped I genuinely think it as

Dar ran Dar ran said:

Sorry for hi jacking this but I was getting a map done on mine soon
but it’s a absolute fly machine loads of instant power pulls hard loads grunt (My old Freelander was no where near this one regarding power)
my question is how would you definitely know one way or the other if it’s already been mapped I genuinely think it as

Click to expand...

A simple check is to find a flat section of road where you can perform a rudimentary 0 to 60 dash. If it does it in less time than the factory time, then there's a good chance it's been remapped. The theory is that cars get slower with age, and seldom achieve the factory 0 to 60 times in the real world anyway, unless they're electric where the opposite is often true.

An app like Torque can record 0-60 times more accurately than a manually operated stop watch.

Nodge68 said:

Difficult to say, as the only way to measure the rail pressure is with the rail sensor signal, which is being augmented by the Synergy, so the reading on live data is false.

I do know the pump has a maximum designed pressure of 1350 Bar, and the ECM limits rail pressure to a maximum of 132,000 kPa which is 30 Bar under the maximum.
So it doesn't take much of a rail pressure increase to push the pump over 1350 Bar maximum designed pressure. I suspect that rust jacking of the pump head plays a part, as the pump does get wet in heavy rain, so rust forms between the pump head and block. However I've also had the Synergy make a rear head seal leak, where there wasn't any rust, so I suspect the pump simply isn't designed to output the pressure a turned up Synergy can ask it to make.

I've proven the concept of leaking too, where a leaking pump on a Synergy has stopped leaking when the Synergy was taken out of circuit, and continued to remain leak free for some months, only to leak again the moment the Synergy was put back in.
Using the Synergy definitely caused issues for me and many others, making a proper remap the best choice on this engine. Don't forget the BMW e46 M47 makes loads more power than the FL1 M47R, and the only difference is injectors, turbo and mapping, all while keeping the pump pressure below the maximum specification.

Click to expand...

That’s interesting about the pressures and leaks. I had read the td4 fuel system description and operation ages ago but can’t remember the details. I thought the system had a 1600 bar limit from memory, probably need to read it again lol. It’s strange how the synergy seems to have effected some vehicles but not others. It would suggest a problem with the specific vehicle as apposed to the synergy due to inconsistent results. I was thinking the same about reading the rail pressure when it’s falsified. Although you could interpret the voltage reading of the sensor to work out the actual pressure.

I had always assumed it just increased the rail pressure in small increments as when I fitted mine I was at the MOT station and ran back to back tests on the smoke meter to see emissions results. I found setting 1 actually reduced smoke output and I guessed this was due to the increased pressure creating better atomisation of the fuel making it burn more thoroughly. Although on the highest setting the smoke reading was huge and I had to clean the machine out after lol.

Would be cool to know what pressures are actually being created, might see if I can figure out a way.

One other thing I assumed about the synergy was the maf input being used to provide more boost. I assumed this as most modern turbo car ecus use the maf as reference for the turbos effort. So a falsified (low) maf reading will make the ecu provide more boost until it sees the right maf number. Although to confirm this I bought a boost gauge which I haven’t fitted yet. Will share results once I have.

I’ve just read up on the td4 fuel system description and operation from rave again as it’s been a few years.
From what I read the maximum pressure the hp pump can make is 1,300 bar at the rail. To achieve this the hp pump intake valve is opened fully by the ecu.
The low pressure pump runs at a constant speed so offers no variable to the hp pump.
The hp pump can only utilise the pump intake valve to regulate pressure and with this fully open 1,300 bar is the maximum it can produce.

This information shows the hp fuel pump cannot be over pressured I’m afraid. If 1,300 bar is max rail pressure with the intake valve fully open on the hp pump then regardless of rail pressure reading, the ecu cannot feed more fuel into the hp pump as the valve is already fully open and the lp pump cannot offer more pressure. Theoretically the only way to overpressure the system would be to fit a lp pump that runs at higher pressure than normal as this would directly effect hp pump output. Hope this makes sense as I do ramble a bit.

The theory of rust jacking effecting the hp pump seated position and that leading to leaks is 100% plausible though. I’ve always noticed many of them tend to look all rusty down by the pump. Sometimes the pumps are rust jacked rather a lot on their own surface from what I see in breakers.

I think I have a way to figure out the pressure difference at the rail between standard and with the synergy box. This is because we have one certain fixed piece of data. With the systems max pressure being 1,300 bar, we can take rail readings with the synergy fitted and work out the difference.

For example, a common mechanics method to test low and high pressure system capabilities/operation is to unplug the hp pump intake valve then crank the engine. Unplugging the valve does exactly the same as the ecu opening it fully for max rail pressure. Live data will show what rail pressure the synergy puts out to the ecu. I’d propose to unplug the valve and crank it with synergy active and see what the rail reading is then. If the sensor states 1,200 bar then we know it will actually be 1,300 bar then we know it’s adding 100 bar on that particular synergy setting.

I think I’ll do this on a nice day and will share the results on here. This should give an actual rail pressure difference for each setting with the synergy box.