lambdas not reading or bad connection 4.6 gems bigas

[Gilbertd]

What is it like towing 3 ton?

A bit scary going downhill but dead stable on the flat. Even the brakes didn't seem to get offended when I asked it to stop (frequently to fill the tank lots of times over 953 miles). Oddly enough, when pulling away on the flat it didn't actually seem to make that much difference, although I doubt I would have won many drag races.

I originally bought a Rangie (the LSE) for the exact reason that it could pull 3.5 tonnes. Although I don't do it often, 4 or 5 times a year I will tow a car transporter trailer to the south of France. Depending on the car I would be looking at a 700 kg trailer with a load of anywhere between 1 and 2 tonnes. The first car I bought to do the job was a Ford Explorer, V6 petrol with the intention of converting it to LPG. Used it once and found that it must be the worst vehicle for towing on the planet, wallowed around all over the place and felt decidedly unstable at anything over 55 mph. It was only rated for a 2.2 tonne trailer too. Decided that, as whatever I got would be any everyday car as well, I couldn't live with the plastic wood (or just plain plastic) in all of the Japanese 4x4's so bought the best 4x4xfar, the LSE which was also comfy and respectable enough to use all the time. Unfortunately, someone had removed the air suspension and put it on springs, so I bought the P38. Ex Greater Manchester police motorway patrol car, bought with MoT, tax, a burst air spring and blown head gasket (but no cracks in the block that I know of). Sorted both those and numerous other minor problems and the LSE may well find itself going to a new home in the near future. As an everyday car now I wouldn't have anything else and I can still tow big heavy things if I want to.

[andy evans autogas]

the legal limit is 3500kg on UK roads though and the speed limit is 60mph.

fit an injection system and blame me for anything i really dont give a shit

I changed my 4.5 97 plate land cruiser to KME about 18months ago from a LEO that I originally fitted in 2002 ...the difference was amazing ,only changed front end got an extra 40 miles per tank towing and its like a brand new car now much more responsive ... well for a land cruiser anyway....

[Gilbertd]

the legal limit is 3500kg on UK roads though and the speed limit is 60mph.

fit an injection system and blame me for anything i really dont give a shit

I know the legal limit in the UK is 60 but only 153 miles of the journey was in the UK, the other 800 or so was in a country with an 81mph limit. And decent roads.......

I wouldn't blame anyone for anything that was my doing. I'll probably remove the single point and fit an injection system anyway. If it gives me better economy then it'll be a bonus, if it doesn't, as long as it isn't worse, that's life.

thats 3500 gross not towed

No, the gross vehicle weight is, as the handbook says, 2780 kgs and the maximum weight of a trailer can be up to 3500 kgs. Hence the plate under the bonnet quotes a gross train weight of 6280 kgs. I must admit you started me doubting it so to confirm I've just been outside. Think about it, if 3500 was the gross train weight on the road, according to the book, you'd need a pretty big helium balloon to get the gross train weight off road down to 1000 kgs!

[LPGC]

Over 5ms petrol injection time at tickover with a hot engine with no load?

Correct me if I'm wrong (because I haven't seen a post where you've said you've seen the Lambda's flicking rich/lean), but if you haven't seen the Lambda's flicking then I'd say it's running open loop for some reason. The most likely reason would be knacked or incorrect Lambda probes or knacked air flow meter or TPS.

These engines usually tickover at about 4ms with a hot engine. 5ms tells me you're probably in 'limp home' open loop mode. Further evidence for open loop mode is the fact that you've noticed the petrol injection durations don't change much when you switch to gas. To confirm, get the engine running on LPG then play with the mixture whilst watching the manifold vacuum. If changing the mixture slightly doesn't affect petrol injection timings (whilst keeping a very similar Map) then you're running open loop and, most likely, rich.

You've said the Lambda's look new. As someone else posted, these engines use a 5-0v Lambda probe. Maybe someone fitted the more generic 0-1v lambda's? In some cases the ECUs can affect the lambda voltage. More often, as the ECU gets older it sometimes seems apparent that the ECUs ground connection seems to suffer (internally) leading to incorrect map / temp and lambda readings.

I haven't read what nozzles are on your injectors but you're going to need more pressure with Bigas injectors anyway, as you would with most injectors on a V8.

So, you need to make sure you're running closed loop first and foremost (one good way is described above). When doing so, bare in mind that when running closed loop, as long as you're within fuel trim limits, the map and gas injection times will stay the same but the petrol injection duration will change. Open loop, the map will change along with both petrol and LPG injection durations.

Hope that helps.

Simon
www.Lpgc.co.uk

[Gilbertd]

Simon, this one is a bit of a continuation of another thread. He can't see what the lambdas are doing as they aren't connected to the Bigas ECU. There also appears to have been a third lambda sensor fitted at some time and that, along with the fact that the car has a blowback valve fitted, suggests it previously had a single point system on it.

That doesn't alter the fact that it may be running open loop as you say. Easiest way to check is to look at the colours of the wires on the lambda sensors. Black, white and grey will be (incorrect) Zirconia, whereas red, black and white will be the correct Titania ones.

[tommo2009]

I am not saying the vehicle can't do it, it is more than capable of towing 3 tonnes, but not on UK roads

[tommo2009]

How will looking at the wires tell him it is in open loop. The 5ms timings are too high at idle, but an obd reader capable of looking at live data is in order here.

Need to ignore the gas system for now and make sure the pterol side is running fine.

[tommo2009]

just thought i would check with the weights, as i got pulled a couple of months ago and was told i was overweight (car and trailer, not me). I was informed that I was 150kg over the 3.5 tonne allowable weight. Todays weight debate got me checking, and i found this

2 Car driving licences held
before 1 January 1997
If you passed your car test before 1 January 1997 you will normally keep your existing entitlements to drive a vehicle with a trailer, with a combined weight of 8.25 tonnes (showing on your licence as C1E (107)) until your licence runs out at age 70. You are also entitled to drive a minibus with a trailer weighing more than 750kg. If you want to keep these entitlements after age 70 you will need to submit an application for lorry, bus or minibus driving licence (D2) and fill in a Medical Examination Report D4, and meet the higher medical standards required of bus and lorry drivers.
If you have subcategory C1E (107) on your driving licence and wish to drive a vehicle and trailer with a combined weight of up to 12 tonnes you can apply for provisional subcategory C1+E in order to take the test. You do not need to get subcategory C1 first, but you have to meet higher medical standards and pass both the category C theory test and the subcategory C1+E practical test.

So from reading this the guy who pulled me and put me on the weigh bridge was talking B*****ks

Didn't book me or anything as the weighbridge was 5 mile from home he just told me to get home and get it unloaded.

[tommo2009]

now I am confused.com just found this under the actual catagories.
B
Cars
Motor vehicle with a MAM of up to 3,500kg, no more than eight passenger seats with or without a trailer – weighing no more than 750kg.
As category B but with a trailer weighing more than 750kg. The total weight of
the vehicle and trailer together can’t weigh more than 3500kg. The weight of the trailer, when fully loaded, can’t weigh more than the unladen weight of the Vehicle.

[Gilbertd]

It all depends on when you passed your driving test. I passed mine in 1974 so can drive a truck up to 7.5 tonnes or a vehicle/trailer combination of up to 8.25 tonnes on a standard car licence.

Licences issued between January 1976 and January 1986

Between 1976 and 1986 your driving licence would have been made of paper with a green background.

The term 'maximum authorised mass' (MAM) means the total weight of the vehicle plus the maximum load it can carry safely.
Group Description
A Motor car and light goods vehicle with up to 9 seats up to 3,500 kg MAM
A Goods vehicle with MAM between 3,500 and 7,500 kg
A Goods vehicle with MAM between 3,500 and 7,500 kg and pulling a trailer, as long as the total weight of both vehicles is not more than 8,250 kg

and

Car licences held before 1 January 1997

All drivers who passed a car test before 1 January 1997 retain their existing entitlement to tow trailers until their licence expires. This means they are generally entitled to drive a vehicle and trailer combination up to 8.25 tonnes MAM. They also have entitlement to drive a minibus with a trailer over 750kgs MAM.

It is not uncommon for plod to make assumptions or to simply get it wrong if the circumstances are a bit out of the ordinary. On one of the fly on the wall TV series a guy got pulled and had his car impounded because it wasn't insured. In actual fact he lived in France and was driving a UK registered car that was insured with a French insurance company while he was going through the process of transferring the car to French plates. This is very common with ex-pats as a UK insurance company won't insure you for more than 30 days outside UK or if you don't have a UK address. Although his car was fully insured for use in any EU country (as all French policies are), the copper insisted it wasn't insured because it wasn't on the database so seized it despite being shown all the documents. I regularly work with the police and have the greatest respect for them but every so often you'll get one who thinks he knows and will stick by it even when he is wrong.

Anyway, back to the plot. Looking at the colours of the wires on the lambda sensors will tell him if it has the correct 5-0 volt Titania ones or if somebody has fitted Zirconia ones which won't work with the GEMS ECU. The problem with using a live data reader is that we are talking about a '96 car, build 4 years before EOBD became mandatory in Europe. I've got a generic code reader that does live data but it only gives limited information, it won't show lambda or long and short fuel trims on my '98 P38 for instance but does show revs and temperature. It does show everything on other later cars and I suspect this is down to the GEMS system not fully supporting the standard. A later Thor with the Bosch ECU would and I suspect the requirement for EOBD compatibility may have a lot to do with why the change was made anyway.

[rossko]

GEMS is certainly only nearly-OBD. Every generic reader I've played with will show live sensor readings - but translated from the physical 5-0v into 0-1V scale for real confusion! - and Short term trims. But never get the Long term trims, just some fixed random nonsense. I recall the airflow reading is funny too, in kg instead of g/s or something.

[Gilbertd]

Just been outside and tried mine. Using a Memoscan U581 on a '98 4.0 litres GEMS Rangie the only live data it displays is Calculated Load, Engine Speed, Vehicle Speed and TPS. Nothing really useful there at all!

[tommo2009]

Just tried mine on a rangie and it gave me all the live data required (1998 model) did cost close on 2 grand though.

[Gilbertd]

I think that's the difference, mines a generic and cost 50 quid.........

[rossko]

hmm, I use a U581 on GEMs just fine. Using the 'generic' option, not 'Land Rover'. Maybe a firmware difference on one side or t'other, but I have not come across a GEMS yet that didn't give the useful stuff.

[Gilbertd]

Weird. My U581 was running HW version 4.5, SW version 4.6 but I recently updated it to HW 4.5, SW 5.2. Exactly the same. Maybe the cars ECU has been flashed with some weird firmware, being an ex police car? The only thing different is that I plug in, connect and simply scroll down to live data rather than selecting a vehicle type first as Land Rover isn't in the list anyway. I thought selecting the vehicle type was only used for decoding manufacturer specific fault codes.

[clj]

Been a few posts then since I last looked at this. So my ecu could be in limp mode. Would I not have light up on the dash if this was the case?

Lambdas are originals looking at the colours of the wires by the way.

Can you recommend a Obd scanner, I was looking at buying a nanocom from blackbox solutions, this should do the things I need.

For the moment it will be ok though, Won't it? I need the RR for a trip to Cornwall in a week.

Edited post, just got the bigas manual out, I think I may have been connecting to the lpg ecu before turning the ignition on or starting engine, hopefully this is the problem. I will try and connect as per instructions.

This wouldn't however affect the tinj petrol timing though I expect, so I don't think this is problem.

Where would you chaps connect the lambda voltage to the ecu, where would I be looking for a bad connection? I followed wires and can see no problems.

[Gilbertd]

As said, the lambda doesn't need to be connected to the LPG ECU, it's just useful to be able to see it while diagnosing problems. You can only connect to one of them and there will be a purple wire in the Bigas loom which connects to the signal wire on whichever lambda sensor is easiest to get to. There is no actual limp home mode in the GEMS ECU, it just goes into open loop so fuels according to a preset map rather than fine tuning according to the lambda signal.

I actually had a play with my U581 at the weekend and found that I can get it to read short term fuel trims. What I had been doing was following the instructions. Connect to the OBD port, switch on the U581 and then turn on the ignition. All appeared to be working except when I start the engine it didn't give me any useful live data. If however, I don't switch it on until after the engine is already running, then it does give useful live data. At least it told me that my short term fuel trims are going to +24.2% at idle but dropping to 0 when driving. That says to me that my lambda sensor heaters aren't working and would explain the intermittent P1185 and P1188 codes that it stores every so often and the fact that it idles a lot smoother on gas than it does on petrol (with mine being a single point system controlled by a separate independant lambda sensor that is working). That may be the fault that you have. I'm told that this is often caused by oil getting into the plugs and that and a combination of the heat from the engine cause the contacts to not make properly. That will be this Saturdays job (as my wife has recently started a new job that involves her working Saturdays, I get the whole day to play with my toys!!!!).

[clj]

Cheers Gilbert, Just checked, following instruction and still no lambda reading (I am certain they used to show up a reading)

So I take it you mean remove the Lambdas and clean the soot/oil out? Not that familiar with them to tell the truth, didn't know they had heaters, but I take it they are internal to warm the surface of the sensing element up?

I was thinking it might have been a connection, but on the Bigas N software they read 0.46v and do not change. You get the odd flick but I think that is interferance or something. So I am presuming this is dirt covering the sensing element which is stopping it working, I have just run some BG44k through the engine because of a @!## idle (might be self inflicked problem), which it has stopped, that was a few tank fulls ago and the fuel tank has been off and cleaned since then because of a leak. The idle speed is a bit lower on petrol than gas by few RPM but both are smooth, LPG is smoother than petrol.

This will teach me for meddling with it now won't it, just want to mach sure its running as best it can.

I take it there will be no harm done to the engine if it has defaulted back to safe map, must be running slightly rich then judging by the tinj petrol timing?

I will try and see if I can find out where the LPG ecu has been connected to the Lambdas there are two possibly according to the wireing diagram, I have a feeling it is in the Range Rovers ECU compartment, there are a lot of small wires running into the back of this compartment from the Bigas ECU, they are all covered with black heat shrink, so I am looking for Purple and Purple/Black, so the top will have to come off. If these are ok I can presume that the lambdas are caked with @!## or not working I guess.

The single lambda is old, and the wire has been cut to it, so I think you are right it must have had a single point on it a some point. The new original Lambdas look pristine, even the wires look clean, red black yellow and white.

This is Fun, My Mrs is going to divorce me at this rate, she needs a job!

Looks like I will be pulling the Lambdas out this weekend too if connections are good.

[Gilbertd]

No, don't take the lambdas out. It is oil (from leaks) that gets into the plug that sits alongside the engine block. The heat turns it into a sort of varnish so there is no connection. Lambdas have to be hot to work so they have a heating element in them. If the power to the heating element isn't there, as I suspect mine isn't, they will only work when the revs are up and they are heated by the exhaust gases, they stop working at idle when the exahust gases have chance to cool down before getting to the sensor.

The lambda signals appear at the GEMS ECU on C507 (the middle plug), pins 33 (left Bank) and 34 (Right Bank). In the plug to the lambda sensors, the wires are 12v ignition switched live for the heater on the red, heater ground on the white, the yellow is signal reference and the black is the actual output. The power comes from fuse 26.