Remapping

[mattytaylor]

Hi all has anyone had there Elgrand remapped and if so has it made the mpg any better because it says on Google it will help to make it better im going Cornwall in July and its going cost so much in fuel but I should of known what I was getting into when buying my Elgrand really

 

[Lpgc]

The benefits or remapping a none turbo engine are very marginal, won't see much difference. It's different with a turbo'd engine because the remap can change things like boost pressure and add extra fuel to go with any extra air the engine sees from increased boost and get a lot more power.

I'll be going to Cornwall in July myself, will be towing my big twin wheel caravan fully loaded, expect I'll be driving a similar distance to you... But even though I'll be fully loaded and towing the caravan it'll cost me less for fuel because I'll be running on LPG at 85p per litre. I've converted over 800 Elgrands to LPG.

 

[Andyzz]

As far as I know you cannot remap the Standard ECU but you can purchase aftermarket ones which have been remapped which do give better fuel consumption I believe the best one is Impul which I use but they are hard to come by and you need to get the correct series 1 2 or 3

 

[mattytaylor]

The benefits or remapping a none turbo engine are very marginal, won't see much difference. It's different with a turbo'd engine because the remap can change things like boost pressure and add extra fuel to go with any extra air the engine sees from increased boost and get a lot more power.

I'll be going to Cornwall in July myself, will be towing my big twin wheel caravan fully loaded, expect I'll be driving a similar distance to you... But even though I'll be fully loaded and towing the caravan it'll cost me less for fuel because I'll be running on LPG at 85p per litre. I've converted over 800 Elgrands to LPG.

Thank you for the reply how much does it cost to have a LPG conversion done

 

[mattytaylor]

As far as I know you cannot remap the Standard ECU but you can purchase aftermarket ones which have been remapped which do give better fuel consumption I believe the best one is Impul which I use but they are hard to come by and you need to get the correct series 1 2 or 3

Thanks for the reply and how did you find one of those ecu

 

[Andyzz]

they sometimes turn up here on the site You can sometimes get them from eBay and Japanese websites but you must know what model you have what year

 

[Lpgc]

Thank you for the reply how much does it cost to have a LPG conversion done

I charge £2095.

 

[LeStempy]

I have a MEC31 Impul ECU for sale. £150 for club members.

 

[kfgas]

Whilst the Impul, Nismo etc ecu's are a very worthwhile performance upgrade particularly with other supporting mods they will only improve mpg very marginally as that is not there prime purpose and in my opinion making certain that what you already have is running the best it possibly can is the best route to go.

Things such as sticking calipers, under inflated tyres, poor tracking, worn spark plugs, clogged air filter dirty maf sensor, sticking pvc valve, dirty injectors etc will all have a negative impact on mpg.

Some of these can be sorted for none or very little money.

Even then the Elgrand does like a drink and this just has to be accepted whether you are running petrol or lpg

 

[Lpgc]

Even then the Elgrand does like a drink and this just has to be accepted whether you are running petrol or lpg

It is better to feed an LPG habit at 85p a litre than a super unleaded habit at £1.74 per litre or a diesel habit at £1.89 per litre though ;-)

I can easily get 20mpg out of my 3.5 Elgrand running on LPG. For a diesel to cost the same to run per mile as my Elgrand getting 20mpg the diesel would have to do around 45mpg. I could get 24mpg out of my Elgrand on a long run if I try, a diesel would have to do around 53mpg to cost the same per mile as that. I might only get 16 or 18mpg on average including local driving etc but that still only costs as much as a diesel getting 34/40mpg. Obviously when I'm towing the big caravan or big boar I get less mpg, a diesel would too. I'll be towing the boat to the Welsh coast and back and towing the caravan to Cornwall and back this year, would hate to think how much an Elgrand size EV people carrier would cost to buy and how many times I'd need to stop to charge, where I'd charge, how long the charges would take and how much the charging away from home would cost. I wouldn't want to pay the price to chage to a diesel engine'd VW van either.

 

[guf]

I have a MEC31 Impul ECU for sale. £150 for club members.

Sadly, that's series 1 only

 

[LeStempy]

Might work with a series 1 BCM in series 2 but couldn't say without trying. MEC31's have more scope for adjustment than the later ones.

 

[Emoller]

Hi there, I’m just solving the problem of the engine yellow warning light on, because of the empty right side catalytic converters, with a remapping, that is at least £1000 cheaper than changing the cats with 2 new sport units, one for each side, what do you think about this???

 

[Lpgc]

Hi there, I’m just solving the problem of the engine yellow warning light on, because of the empty right side catalytic converters, with a remapping, that is at least £1000 cheaper than changing the cats with 2 new sport units, one for each side, what do you think about this???

If your warning light is on it won't be because of empty catalytic converters... and replacing catalytic converters won't fix it.

Perhaps whoever 'emptied' the cats broke a lambda sensor in the process?

What error code(s) are you getting?

 

[Emoller]

I changed the 4 sensors and nothing happened, still yellow engine warning light on?

 

[Emoller]

P0031, P0051, P0037, P0057

 

[Highway Dave]

Codes do seem to point to lambda problems so simon was on the ball I think.
Have you actually cleared codes ( easily forgot), have you used aftermarket sensors ( Elgrands don’t like this ), have you done a visual on wiring leading to the sensors for damage.
If all is ok then the sensors could simply be reporting other faults , usually simple ones like exhaust leaks vaccine leaks etc.
The usual thing here “for me” would be damage to plugs or wiring though or cheap sensors used,
@Lpgc once told me not to clean lambdas let alone change them unless absolutely certain they were bad ———these units can be very sensitive

 

[Highway Dave]

I meant vacuum not vaccine but can’t seem to correct lol

 

[Lpgc]

The purpose of lambda sensors is to detect oxygen in the exhaust gas, the more oxygen in exhaust gas the leaner the perceiced air/fuel mixture. But they cannot work properly unless the lambda sensors are hot. Being in the exhaust they can get hot anyway but not always hot enough to work properly, so they have a built in heater. The heaters might just be a simple heating coil, the heaters usually (and in the case of Elgrands do) have their own power feed and their own earth wire which is separate from the signal wire and separate from the earth wire for the (oxygen level) signal that the lambda sensor generates.

Those 4 error codes point specifically to the heater circuits of the lambda sensors (of all 4 lambda sensors). The OBD standard has different error codes for short circuit and open circuit heater circuits but the OBD on our Elgrands is Nissan's JOBD which isn't standard OBD and the error reporting of Elgrands isn't as accurate or as telling/directly pointing to errors as standard OBD... It doesn't say whether the problem seems to be short circuit or open circuit. Also on our Elgrands if a heater circuit on only 1 of the lambda sensors is shorted out the JOBD can report more than 1 or even all 4 lambd sensor heater circuits are shorted out. There can be other problems too, such as the power feed for a lambda sensor heater circuit can become shorted to the signal wire internal of the lambda sensor.

If you changed all 4 lambda sensors and the error codes persist then it could point to a wiring or ECU problem. But as Dave said the error codes won't be quick to self clear, so if you changed all 4 you might have fixed the problem but if you didn't clear the error codes you'd still have the MIL light lit until you fixed the problem (by changing the sensors) and cleared the error codes.

It would be a massive coincidence if all 4 lambda sensors had failed heater circuits at the same time (open circuit or closed circuit). You'd also have this condition reported if all 4 lambda sensors were simply not plugged back in after messing with the exhaust. Or as implied above, on an Elgrand you could get the same reported condition if only 1 of the sensors was shorted. In the latter case it is possible to find which one is shorted by unplugging one at a time, clearing error codes with just that one unplugged and seeing if you get error codes for all 4 or just the 1 you have unplugged.

Watching live OBD data can help find which if any lambda sensors have heater circuit shorted to signal circuit because that will be the 1 that still shows rich mixture during engine over-run fuel cut off conditions. This can be used as a pointer in knowing which sensor to unplug first if you take the route described at the end of the last paragraph (unplug one at a time until there is only 1 fault code).

Say again that if you have error codes pointing to heater circuits for all 4 sensors, the chances are that either someone forgot to plug all 4 sensors back in after doing exhaust work or only 1 sensor has a heater sensor problem but Elgrand JOBD incorrectly reports heater circuit faults on all 4 sensors. You can also have a condition where a shorted heater circuit on 1 sensor messes up the signal from other sensors, in which case JOBD points (with error codes) to incorrect signal from other sensors but such error codes should be taken with a pinch of salt and the best way to determine what's really going on is to watch live data.

3.5 or 2.5? On 3.5's all 4 sensors are narrowband and produce a signal between 0v (lean) and 1v (rich). Most 4 wire 0-1v sensors can and do work but when we talk about aftermarket sensors we normally mean cheapo sensors and most cheapo sensors are not very reliable or long-lived. Another thing about cheap sensors is they might come without a wiring plug or incorrect plug in which case which makes it necessary to wire the plug from the old sensor onto the new sensor... in which case it's very important not to get the wiring wrong. Most OEM sensors are better than cheap / generic sensors, even if they're meant for another vehicle as long as they're the correct 0-1v 4 wire spec. If it's 2.5 the front 2 sensors are wide band (the 2 rear sensors are still narrowband and same spec as on the 3.5), wide band is a different kettle of fish to narrow band sensors, with wide band sensors you need to fit the exact correct spec for the vehicle.

 

[Emoller]

I bought the parts from JDM Car Parts, believed they were good quality, are they?
Anyway thanks for that long and detailed explanation and advice, I really appreciate the feedback!