l320 reducer options?

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mgrover
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Re: l320 reducer options?

#21 Post by mgrover » Fri Mar 13, 2020 9:21 pm

Hmm we'll see how it goes with new reducer then.

I'll stag away from those settings and yeah it used to warm up on petrol on the brc system.

Ahh that might be a bit harder given I boot it on ring roads :p

Almost exclusively starts on lpg, maybe within 10-20 seconds it switches. Because of this it's rough at startup to the point where it almost stalls then recovers.

I don't plan to do it myself after the reducer switchover

It's been throwing lean codes forever and the only thing left is either the fuel pump or I don't know anymore. Smoke test been done, software updated, pcv done, both heads rebuilt and new timing set. Fuel pressure at the rail is 35-45psi. Am told its meant to be around 65 so am outta ideas.

There is no fuel return for the petrol, also am getting lean codes on both banks

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Re: l320 reducer options?

#22 Post by LPGC » Fri Mar 13, 2020 10:00 pm

Since it's a supercharged model (jag engine) it wouldn't be fitted with a petrol return as standard, instead the petrol ECU controls fuel pump output and monitors fuel pressure (petrol pressure has it's own closed loop system) but the petrol pump is always run and has a minimum output. The minimum output means that when running on LPG (so petrol isn't being used by the engine) petrol pressure will increase to an unusually high pressure if a physical fuel return isn't fitted by the LPG installer. The high pressure reading then causes the petrol ECU to decrease petrol injector pulse length (higher pressure to injectors means injectors don't need to be pulsed for as long to flow the same amount of fuel). Since the LPG system 'piggybacks' from petrol injector pulse length this also means that LPG injector pulses also get shorter with increasing petrol pressure readings - you cannot get good results running on LPG unless petrol pressure readings are addressed. The best way to address petrol pressure readings is to fit a physical fuel return (which also prevents the petrol pump and all other petrol system components from working at high pressure) because this sees the pump work as normal, but it is possible to fit an electrical fuel pressure emulator which fools the petrol ECU into reading 'normal' petrol pressure despite very high petrol pressure.

If you're taking fuel pressure readings when running on petrol and using a mechanical fuel pressure gauge and are seeing 35/45psi it doesn't prove anything regards whether a physical fuel return has been fitted, a fuel return (or emulator) should be inactive anyway when running on petrol and running on petrol fuel is being drawn off all the time, it does however seem to prove the fuel pump and it's closed loop system are working OK (Iirc fuel pressure is normally around 375kpa on these engines which is around 3.6bar). If you're taking fuel pressure readings when running on LPG and using a mechanical fuel pressure gauge and are seeing 35/45psi then it will (must) have a physical fuel return fitted. If you're taking fuel pressure readings from OBD and fuel pressure seems good then it may have a physical return or may just have emulation but in either case at least the fuel pressure reading has been addressed to allow decent LPG calibration to be possible. If you're unsure about fuel pressure on an LPG converted Ford/Jag/supercharged Rangerover engine and are unsure if you have a fuel return or emulator fitted you've got to check fuel pressure running on both petrol and LPG (2 checks). Some of the BRC ECU's and some of the AC Stag Q ECUs feature onboard petrol pressure emulators but Stag (and other manufacturers) produce standalone fuel pressure emulators anyway

But if you had a problem with fuel pressure readings you'd have OBD errors for fuel pressure anyway, so if you're not getting codes related to fuel pressure it's unlikely you have a fuel pressure reading problem. In which case mixture related codes are more likely LPG system setup/calibration related. An incorrectly setup/calibrated LPG system can cause codes to be generated when running on petrol.. if calibration is wrong and fuel trims are learned when running on LPG (so codes less likely on LPG) codes can arise when the engine runs on petrol. For good results on both fuels LPG fuelling has to closely match petrol fuelling. In my experience it is unlikely an installer who fits Stag would calibrate the system well enough to prevent mixture related codes (and most would fit an emulator instead of a proper fuel return), they usually rely on autocal but autocal (which doesn't usually work very well anyway) definitely won't work very well on a vehicle which responds to petrol pressure readings, because the petrol pressure readings won't be the same (with either a physical fuel return or emulated fuel pressure) as they are when really running on petrol and autocal cannot take into account petrol pressure readings. To calibrate any install on a vehicle with a petrol pressure sensor properly the installer has to calibrate manually while watching OBD live data.
Last edited by LPGC on Fri Mar 13, 2020 10:47 pm, edited 2 times in total.
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Re: l320 reducer options?

#23 Post by mgrover » Fri Mar 13, 2020 10:28 pm

this lean code issue has been going on since I bought the car even when i ran petrol for a month and reset the adaptations. so something is definitely wrong when running on pure petrol.

i did notice the petrol fuel pressure change when switching from lpg to petrol.

with this recent stag ECU I now get a P0088 which is complaining about high fuel pressure.

tbf the stag installer suggested the fuel return line as well, its one theory as to why the petrol pump is toast, well that and coupled with the fact it struggles at high rpm

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Re: l320 reducer options?

#24 Post by LPGC » Fri Mar 13, 2020 10:59 pm

Running high fuel pressures can toast petrol pumps on RRSC's (and Jags and other Ford based stuff), which is why it's better to have a physical fuel return than an emulator on these vehicles. But toast would usually mean the petrol pump or it's electronic driver would no longer work and since yours will still run on petrol it seems your petrol pump isn't broken yet. Another thing that can lead to incorrect fuel pressure is if something interferes with the vehicle's canbus - the petrol ECU communicates with the petrol pump PWM electronic driver module via canbus so if the canbus doesn't work properly it can affect fuel pressure. You don't want anything like Stag ISA2/3 OBD connection affecting the canbus so don't connect the LPG ECU to canbus.

It's normal to see fuel pressure change with a physical or emulated pressure. The main problems regards running on LPG are if it changes too much. With a physical return it's necessary to get the size of the jet in the return about right (single jet flows about the same as the 8 petrol injectors at around mid engine loads), with an emulated pressure the electrical signal it's necessary to set it (turn a pot) so that it returns around the same fuel pressure as running on petrol would.

If there is no return and no emulation, or if return nozzle size is too small (a jet must be fitted in the return line to bleed a similar amount of fuel as fuel injectors would use), or if emulation provides a reading of too high fuel pressure you'll get the high fuel pressure error code. No chance of calibrating the LPG system properly (or running on petrol properly) with such code present.
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Re: l320 reducer options?

#25 Post by mgrover » Sat Mar 14, 2020 2:39 pm

If I wanted to have a return line fitted, and while there the fuel pump/filter changed out plus the kme fitting and calibrating so the entire system is just right. How much you think it'd set me back

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Re: l320 reducer options?

#26 Post by mgrover » Mon Mar 23, 2020 8:08 am

ive hooked up the KME reducer. it seems to be holding up better. One issue I did have is that I don't have a connector for the temperature sensor so i had to try start without. But it wouldn't switch to LPG without it. So I just kinda put the cables into the connector till i can get a proper connection for it.

the tanks on low atm so it still switched back right at the top of the rev range but the double reducer system used to instantly switch back when i planted my foot. I do need to get some flexi hose for the gas because right now the valve is connected directly to the gas line and directly to the reducer so placing it neatly is becoming hard.

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Re: l320 reducer options?

#27 Post by mgrover » Thu Mar 26, 2020 12:34 pm

fuel return line fitted and fuel pump changed. and kme reducer installed

the KME is shit. So you were right :P

I still get the P0088 popping up which is odd but lets see if it disappears.

Am going to reset the cars adaptations and go from there.

I'll probably get to get the Magic Jet 3 Extra since I think I may of found someone who will take the KME extreme

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Re: l320 reducer options?

#28 Post by LPGC » Fri Mar 27, 2020 12:45 pm

Whether or not a part performs poorly can depend on whether it's used in the right application.

How did you fit the fuel return and what sized nozzle did you fit in it?

Are you sure there is no electronic fuel pressure emulator fitted? If there is it could be this that's telling the petrol ECU fuel pressure is high despite it having the physical fuel return fitted.

Regardless of what reducer you fit, if the car OBD system is reporting petrol pressure issues you'll still have problems.
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Re: l320 reducer options?

#29 Post by mgrover » Sat Mar 28, 2020 3:45 pm

LPGC wrote:
Fri Mar 27, 2020 12:45 pm
Whether or not a part performs poorly can depend on whether it's used in the right application.

How did you fit the fuel return and what sized nozzle did you fit in it?

Are you sure there is no electronic fuel pressure emulator fitted? If there is it could be this that's telling the petrol ECU fuel pressure is high despite it having the physical fuel return fitted.

Regardless of what reducer you fit, if the car OBD system is reporting petrol pressure issues you'll still have problems.
I didn't fit the fuel line but the lpg mechanic did.

https://photos.app.goo.gl/QUbYSbrVwZRetj8z5

That's the bad boy. I am pretty sure given he already dropped the tank to replace the fuel pump which was on its way out. I think he said the nozzle was 2mm. He tried a smaller nozzle that he did with a previous install on a similar car but it didn't seem to be working well. I did check the OBD reading while on lpg and it was 33psi instead of the 70psi it used to be at on lpg so it seems fine?

I found a polish website that also confirms that the KME extremes are basically @!## for hard driving or turbo/super charged engines. Although this was me reading off google translate so anything could be occurring.

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Re: l320 reducer options?

#30 Post by mgrover » Sun May 03, 2020 12:39 pm

so a return line seems to be fitted but it still is freaking out about the high pressure. which it does go quite high, 60-70psi when lpg is enabled. are you going to be open anytime soon Simon? I think we've reached the limit of my knowledge on the matter tbh

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Re: l320 reducer options?

#31 Post by LPGC » Tue May 05, 2020 12:27 pm

I'm still doing LPG work that can be done while maintaining social distancing...

The biggest jobs such as installing a complete LPG system are the easiest to maintain social distancing with - E.g. When I'm installing a new conversion it involves the customer dropping the vehicle off in the yard here and collecting it when I've finished the conversion at least a couple of days later.. I did one conversion where the owner left his car here a few weeks, I didn't start work on it for a week, did the conversion, he didn't pick it up for a week after I'd finished during which time I hadn't been near his car. Still wear PPE etc when I got in his car and he wore PPE when he picked it up.

Usually with diagnostics and repairs the customer would explain the symptoms and we might go for at least one test drive together. Obviously we can't go for test drives together during lockdown but you could explain symptoms from a distance and I could do test drives/calibration myself. Even better if you could drop it off and leave it with me for a day or two?

The other day I called at a re-spray garage to fix a Prins LPG system on a Focus ST that hadn't worked since the present owner had had the car. The garage was closed in the general sense but the proprieter met me there and we kept our distance.

It can be done and with no risk of spreading virus's as long as it's done sensibly.

Never been so quiet at work... but I've been commandeered into doing other stuff, built a patio etc etc...
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Re: l320 reducer options?

#32 Post by Gilbertd » Tue May 05, 2020 2:03 pm

A mate runs a mobile air conditioning business. The way he has got round social distancing is the customer books him to come to their house, he pulls up outside and calls them to say he is there, they come out of the house and leave the keys on the bonnet and go back inside. He then does his bit, tests the AC is all working as it should and packs his gear back into his van. Leaves the car keys on the bonnet, sits in his van and calls the customer to tell them he is all done so they can come out of the house to collect the keys. Payment by Paypal or bank transfer so he never has to go near the customer at all.
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Re: l320 reducer options?

#33 Post by LPGC » Tue May 05, 2020 2:59 pm

Gilbertd wrote:
Tue May 05, 2020 2:03 pm
A mate runs a mobile air conditioning business. The way he has got round social distancing is the customer books him to come to their house, he pulls up outside and calls them to say he is there, they come out of the house and leave the keys on the bonnet and go back inside. He then does his bit, tests the AC is all working as it should and packs his gear back into his van. Leaves the car keys on the bonnet, sits in his van and calls the customer to tell them he is all done so they can come out of the house to collect the keys. Payment by Paypal or bank transfer so he never has to go near the customer at all.
Seems totally sensible to me, not strictly speaking essential but no chance of anyone concerned spreading virus's. The customer is happy because they're getting the job done at a convenient time, the worker is happy because he's still earning. Same sort of deal when I visit a customer premises or the same kind of thing if the customer visits me. Not that I've had much work on!
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Re: l320 reducer options?

#34 Post by Gilbertd » Tue May 05, 2020 8:21 pm

He stopped working for a week or so when lockdown first started then realised they were saying you could only go out if you were going shopping, for medical reasons or to work, so he figured he would be OK going out to work.
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Re: l320 reducer options?

#35 Post by LPGC » Tue May 05, 2020 11:50 pm

Gilbertd wrote:
Tue May 05, 2020 8:21 pm
He stopped working for a week or so when lockdown first started then realised they were saying you could only go out if you were going shopping, for medical reasons or to work, so he figured he would be OK going out to work.
I agree. Every person who can carry on working safely is one less person furloughed, makes sense for the economy too.
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Re: l320 reducer options?

#36 Post by Brian_H » Tue May 05, 2020 11:56 pm

Equally any that can still do their job from home means less cars on the road, so all good there too. Sadly not an option for me to do either at the present time though. Good to see some are still managing to function though, last thing we need is a takeover of the large chains squeezing everyone else out of business.

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Re: l320 reducer options?

#37 Post by mgrover » Thu May 07, 2020 2:41 pm

LPGC wrote:
Tue May 05, 2020 12:27 pm
I'm still doing LPG work that can be done while maintaining social distancing...

The biggest jobs such as installing a complete LPG system are the easiest to maintain social distancing with - E.g. When I'm installing a new conversion it involves the customer dropping the vehicle off in the yard here and collecting it when I've finished the conversion at least a couple of days later.. I did one conversion where the owner left his car here a few weeks, I didn't start work on it for a week, did the conversion, he didn't pick it up for a week after I'd finished during which time I hadn't been near his car. Still wear PPE etc when I got in his car and he wore PPE when he picked it up.

Usually with diagnostics and repairs the customer would explain the symptoms and we might go for at least one test drive together. Obviously we can't go for test drives together during lockdown but you could explain symptoms from a distance and I could do test drives/calibration myself. Even better if you could drop it off and leave it with me for a day or two?

The other day I called at a re-spray garage to fix a Prins LPG system on a Focus ST that hadn't worked since the present owner had had the car. The garage was closed in the general sense but the proprieter met me there and we kept our distance.

It can be done and with no risk of spreading virus's as long as it's done sensibly.

Never been so quiet at work... but I've been commandeered into doing other stuff, built a patio etc etc...
ill have to let you know cause now the ACE leaks have started so time for some £300 pipes and a lotta swearing. also seems I need to change out my air sensors because am out of ideas why the engine is now throwing lean codes on petrol even after resetting adaptations a few times.

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Re: l320 reducer options?

#38 Post by LPGC » Thu May 07, 2020 10:24 pm

You might try this...
Clear OBD codes and then immediately turn the engine off and leave it until the engine has cooled down (even better overnight). Start the engine (run only on petrol since your LPG calibration and/or fuel return are probably bad), don't let the engine idle long, immediately set off driving and don't drive with a constant throttle (keep changing the accelerator position).

Supercharged Rangerovers have particularly fussy OBD systems, they can repeatedly generate lean/rich etc type codes if LTFT's haven't been learned properly because it causes STFT's to max/min out. When STFT's are maxxed/minned out LTFTs are not steered so are never learned and STFTs reaching an extreme can cause an error code in itself. By continually moving foot on the accelerator it can prevent a time-out while STFT's are at an extreme and can give LTFTs a better chance of being steered in the right direction by STFTs.

Other than that, they are very sensitive to vacuum etc leaks. Even if the evap purge valve flows an unusual amount of air the ECU may pick up on it and throw a code.
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Re: l320 reducer options?

#39 Post by mgrover » Fri May 08, 2020 7:43 pm

LPGC wrote:
Thu May 07, 2020 10:24 pm
You might try this...
Clear OBD codes and then immediately turn the engine off and leave it until the engine has cooled down (even better overnight). Start the engine (run only on petrol since your LPG calibration and/or fuel return are probably bad), don't let the engine idle long, immediately set off driving and don't drive with a constant throttle (keep changing the accelerator position).

Supercharged Rangerovers have particularly fussy OBD systems, they can repeatedly generate lean/rich etc type codes if LTFT's haven't been learned properly because it causes STFT's to max/min out. When STFT's are maxxed/minned out LTFTs are not steered so are never learned and STFTs reaching an extreme can cause an error code in itself. By continually moving foot on the accelerator it can prevent a time-out while STFT's are at an extreme and can give LTFTs a better chance of being steered in the right direction by STFTs.

Other than that, they are very sensitive to vacuum etc leaks. Even if the evap purge valve flows an unusual amount of air the ECU may pick up on it and throw a code.
i think its the sensors tbh. ive tried everything in terms of software updates, several smoke tests, pcv valve, new fuel pump etc etc. my trims at idle are up and down, they cant seem to decide if there lean or rich, although the ltft at idle is fine but the ltft at 1.5k rpm is like 20%

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Re: l320 reducer options?

#40 Post by LPGC » Fri May 15, 2020 7:26 pm

You can sometimes reset learned (and mis-learned) values such as fuel trims by disconnecting a petrol injector, start the engine to provoke injector disconnected OBD codes, turn the engine off, reconnect the injector and clear OBD codes. Petrol injectors on these engines are difficult to access but you can disable a full cylinder bank of 4 petrol injectors by disconnecting the injector bank's multi-plug (one at each side behind charge coolers).

Don't read much into fuel trims before things have settled down (self tests / IM readiness have been passed) - the standard model for fuel trims (the way we usually think of the way they work) isn't always the way they actually work on some vehicles, especially before things have settled down. In my last post I suggested a way of helping 'settling down' and I've just added to that in this post (above).

You could have a poorly MAF though? Are the oxygen sensors the correct part? Is the standard air filter fitted or something aftermarket like a K&N cone?
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