l322 tank vent

having similar issues as below which was posted on another site not a prob at moment but would rather get it sorted, any suggestions folks ?

"Hi All having a bit of a problem with my Rangie its a 2002 4.4 range rover with LPG. The energy management light came on today I plugged in a diagnostic computer and it had a few problems, the one that brought on the light was misfires. but there was also tank vent valve and Electronic thermostatic control. I also could not get the petrol cap off when trying to fill up (running on gas most of the time so use very little). I reset the codes and had a drive of about 12 miles when checked again the electronic thermostaic control and the tank vent valve were on again but no engine light. I believe I am getting a vac in the tank because of the valve giving me a misfire. Anyone had this problem and what is the repair.The thermostatic control code is 140 which in the manual says lambda is the computor wrong?"

prob a few will agree inc ant (saint) you will now & again get a eml light come on when lpg is fitted due to changeover but this tank vent etc is bugging me also I have no probs filling up with fuel & no tank pressure(air hissing) although I did notice the gun at filler station has been hard to fit into the filler neck on the last few occasions ?

thanks in advance will

Just been looking at the L322 Tank system in the manual and also the Electrical schematic for the Fuel delivery and Fuel Pump....I can't seem to find a 'Tank Valve'.

The NAS fuel system does have a vapour reclaim and Tank Leakage Detection system fitted (Euro's don't from what I can gather).

The Tank Vent is piped into the Charcoal Canister (mounted on the front face of the Tank under the plastic protection guard) and also it is plumbed into the Vapour Separator (on top of the tank) and finally exits around the Fuel Filler Cap.

If you are not having hissing issues or hesitations when running on petrol, I wouldn't say you have a blocked breather.

As for the difficulty in getting the filler into the neck...that is mostly likely because the neck is narrow and you have to get the filler pretty square-on to get it in the hole! re you getting any resistance when putting the filler in - i.e. like pushing against and airpocket??

Also are you having filling issues - i.e. it keeps clicking off every couple of seconds as this could indicate the tank isn't venting properly as new fuel goes in...?

The EML is only there to indicate problems with the emission control systems of the engine - Injectors, MAF, Knocking, Lambdas, ignition, misfires etc etc....

You are quite right, LPG powered cars have a tendency to throw EML's (mine does on occasion - Bank 2 Upstream Lambda gone Max Signal is the usual one for me) This is mainly due to the change over from Petrol to Gas, although it is meant to be a seemless and sequential change over....after one injector has injected petrol, the system switches that cylinder to gas and the change over ripples along all the cylinders until they are all on gas, but on occasion some gas or petrol gets injected into same cylinder, LPG is injected into the intake manifold above the cylinder it feeds - sometimes not all the gas is inducted and is left in the manifold when the other cylinder sucks its air charge in and this contains the gas from the other cylinder - thus gets a double dose and the ECU detects this as over fuelled and throws a fault light.

My 735 (same engine as the Range Rover only the 3.5 litre version - M62TUB44 (RR) and M62TUB35 (735) ) and this throws a fault with the same O2 sensor as the Range Rover - only more often for an unknown reason!

It can happen if the O2 sensor starts getting fouled up....in America where they fit Magnaflow exhausts they fit sparkplug anti-foulers to the Lambdas to take them out of the gas flow and make them a little less sensitive to exhaust gas changes and also to prevent them getting fouled up to often.

As for the Electric Thermostat issue...the M62 uses an electrically heated thermostat which is controlled by the engine ECU which contains a cooling map....the thermostat works just like anyother stat with a metal coil to open and close it...

The Engine ECU tries to retain heat in the engine at a slightly higher than normal 105degC as this promotes better combustion and better economy, but when the engine is working hard during acceleration, towing, hill climbing, off roading etc, the ECU uses a heating coil in the thermostat to open the stat further and allow more water flow for more cooling....

Mounted on top of the stat is an electrical connector...unfortunately in true BMW/RR fashion, over time coolant can seep out and start tracking up the wiring corroding it and in worst case, track all the way up to the ECU corroding the connections there too....

I thought I had this issue with mine, but it turned out to be a chaffed wire where it passes under the engine acoustic cover....quick repair and all is well (fingers crossed)

The problem with coolant in the E-Box is more common on the BMW models but it has been known on the Range Rover too....

What are the exact symptoms you have Will ??

Saint.V8 said:

What are the exact symptoms you have Will ??

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thanks ant it runs fine on petrol & lpg but ive had eml come on a few times recently within the space of a month or so.never had none before tbh it does not run no different & it was saying rich bank 1,rich bank 2.seems to be when its left idling for long periods,the only thing to do with fuel system maintenance recently was a new fuel pump, so I cleared faults & started to investigate more with my diagnostics( old solus-pro running 13.2 but does the job) & found tank vent & elec therm con.the faults will clear but its hiding deep.i ran a health check on entire vehicle & no other faults are present or pending everything in live data is as it should be,when you go in depth its still in there & can be found & cleared but returns when engine is restarted it doesn't even need to be driven.no tank hissing issues,no probs with slow fuel filling either & no difference in the way it drives.

I can only assume that the tank valve fault is there because the ECU 'thinks' it should be but isn't (as it was only available on the NAS versions - Parts list attached and highlighted) and can be ignored - you said it was hidden in the depths on the diagnostic menu/options.

As for the stat problem, take a look at the electrical connector on the stat for signs of corrosion and also check the wiring thereto...The fact it is also hidden deep in the menu/options could mean it is another sensor/system the Euro spec doesn't have as the common fault for Stat problems is 'Electronic Thermostat Map Cooling Fault' (or something like that).... if you are not having overheat issues or loss of coolant, I would say it can be ignored.

As a for instance, I keep getting EBV Faults in the ABS ECU....but the L322 doesn't have EBV system fitted so can be ignored....sometimes the ECU's are looking for inputs that don't exist depending on spec, market and system setup.

As for the EML and the Running Rich issue....the ECU runs different fuel maps and it uses adaptive control for fuelling that can adjust mixture within set boundaries according to the fuelling map.

Long Term Fuel Trims are used to control idle mixture and Short Term Fuel Trims are used to control mixture at load....

LTFT is known as additive and STFT as Multiplicative.

(I attach a PDF from BMW about the Fuel Trims and how they work)

If yours is starting to run rich at idle, that could indicate too much fuel is injected to satisfy the fuel map....from a leaking petrol injector or a block air filter, or even a MAF giving false air information.

If it happens on the change over from Petrol to Gas it is more than likely the change over isn't quite sequenced correctly and the cylinder is getting a shot of fuel and gas at the same time causing a Rich running signal...

If it happens whilst running on gas alone, it could mean the LPG system needs to be recalibrated to readjust the LPG fuel maps as it could be over injecting LPG....

If it happens on whilst on Petrol it could be a leaking injector or fuel pressure to high...

I would also check the MAF in all cases as this gives the Air Quantity information the ECU uses to measure out the amount of fuel...if that is erroneous, it could be injecting more fuel than needed for the actual amount of air inducted and the Lambdas are confused giving a Rich signal...

A check and clean of the Lambdas probably wouldn't go a miss either.

thanks ant top man im going to plug it back in in a bit faults from eml will still be logged so ill upload some pics also I can get into tank vent on menu & test operation if its actually fitted

ok no eml present so ran vent test no noises air or electrical infact nothing as if there isn't one there,heres some live data shots what you think

Cos you ain't got one bud....

Tank Vent Valve is only NAS spec vehicles only....

As for the Electronic Thermostat control code...unplug the multiplug on top of the stat body and measure resistance across the stat heater coil....found this on another forum...

Hi All sorted now the code 140 is the electronic thermostat (Standard thermostst with a heater) Heater was open circuit fitted a new one all codes on pertol reset and staying off. Fault codes coming in on gas were bank 1 and 2 mixture adaption control limit reached. watched this output on the hawkeye and the gas was going to 25% where petrol reached about 18% this was at cruise at about 2200 revs (I guess this is leaning out of the mixture). tuned the gas using the tartarini software and bingo (Fingers crossed) no ecu faults.

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