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PostPosted: Tue Nov 15, 2016 8:33 am 
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Tec99 is lambda controlled. The cutting out will be caused by the mixture going either very lean or very rich on the over-run but you will need the cable to find out which and deal with the problem. WTV will do you one here http://www.lpg-kits.com/interfaces.htm and scroll down to Tartarini.

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PostPosted: Tue Nov 15, 2016 11:23 am 
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He could use a multimeter on lambda signal to see what's going on regards mixture.

Comparisons could be done between air filter connected and disconnected (cut out comparison with multimeter connected). Pretty certain ram air will be having a negative effect with the snorkel fitted and like Dai said ram air could have a negative effect even with the standard intake arrangement. If it doesn't cut out with the air filter disconnected then immediate problem solved - it should be a bit leaner with the air filter disconnected if anything unless ram air is involved. If it will idle when not moving and the exhaust doesn't stink rich then it's pretty certain it's going lean rather than rich and leaner still (on over-run) causing the cutting out.

There may be other points contributing to the cutting out but best to start by removing ram air potential. Other points would be maladjusted of duff reducer, broken stepper valve, broken lambda, etc.

If buying the cable it's a good thing it's Tec99 and not an earlier version of Tartarini, need an old laptop or to faff with Dosbox for anything much older. Tec99 runs on Windows and is similar to setup as usual AEB175's, still my AEB USB lead (with Tartarini adaptor) doesn't work with Tec99, I have to dig out a different USB to serial cable and use an old Tartarini serial cable when working on Tec99 systems - The one in Gilbert's link may work, I have one of those too but I don't have a vehicle here with Tec99 fitted to try it on. I'll have an old Tec99 ECU somewhere, if I get time I might dig it out and connect it to a battery to try interfaces.

Simon

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PostPosted: Tue Nov 15, 2016 7:47 pm 
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It all sounds very complicated I'm not to good with electric is there any manual adjustment's
Little tweeking with say screwdriver ish that could be done :?:


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PostPosted: Tue Nov 15, 2016 8:46 pm 
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That's what it may result in eventually but you need to be able to see the affects of the tweaking. Random tweaking, especially on a lambda controlled system which will fight against what you are doing, will almost always only succeed in making things worse. The lambda sensor gives feedback to the controller telling it if the mixture is rich or lean. Using that, the controller adjusts the mixture to keep it correct. Now it might be that the lambda sensor has died which will result in it telling the controller that the mixture is too lean making it make it over-rich. It might be that the vaporiser has reached the end of it's useful life and the controller doesn't have enough range to adjust over to keep it correct. That's just two possibilities but in both cases, you need to know what is happening.

Using a multimeter is reasonably easy. You connect the black wire on the meter to ground and the red to the lambda sensor signal wire (Probably a black wire on the sensor but it will, or at least one of them will, have a wire connected to it that goes to the Tec99 controller). Then drive the car, the meter will read between 0V and 1V. 0V means that the engine is running lean or the sensor is dead, 1V means that it is rich. Flip flopping between the two while driving is what you would hope to see.

Where in the country are you?

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PostPosted: Wed Nov 16, 2016 7:16 am 
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I'm in Southampton Hampshire
What setting on the multi meter would it be ?
Is the lambda sensor the bit in the hose that goes
From vaporiser to a collar joining the intake
On plenham chamber ?


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PostPosted: Wed Nov 16, 2016 9:31 am 
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As you want the meter to read between 0 and 1 volt, on the lowest volts scale. The lambda sensors are the two things that Land Rover fitted in the exhaust downpipes just before the cats. They detect the amount of Oxygen in the exhaust to tell the petrol ECU if the mixture is correct or not. When the Tec99 was fitted, a feed will have been taken from one of those to connect to the Tec99 controller. It is that wire you need to connect your meter to.

In the LPG system you have the vaporiser that turns the liquid gas into vapour and sets the pressure to very slightly above atmospheric pressure. This gas is sucked into the engine through the mixer, the collar at the throttle body. To tune the mixture, the bit in the hose between the two is a stepper motor controlled valve, the actuator. The lambda sensor tells the controller if the mixture is rich or lean and the controller adjusts the actuator to alter the mixture to keep it correct. At least, that is how it is supposed to work but if the lambda sensor has died then it will be adjusting based on duff information. If the vaporiser is tired it won't be able to keep the pressure constant. If the actuator has stuck, it can't adjust the mixture. That is about the only other thing you could try without getting involved in electric. Take the actuator out of the hose and give it a good blast with carb cleaner.

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'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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PostPosted: Wed Nov 16, 2016 10:39 am 
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Oh those lambda sensor.I thought the LPG
System had them aswell mine has no cats or
Lambda sensors


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PostPosted: Wed Nov 16, 2016 11:21 am 
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Wouldn't be much point of a closed loop system like Tec99 without a lambda sensor.

In the gas pipe between the reducer and mixer there will be a flow control valve, is this electronic (as in wires to it) or just a manual adjuster?

Simon

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PostPosted: Wed Nov 16, 2016 12:27 pm 
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flyingbanana wrote:
Oh those lambda sensor.I thought the LPG
System had them aswell mine has no cats or
Lambda sensors
A Tec99, or any other closed loop system for that matter, isn't going to work then. It'll see no input so assume a lean mixture and run maximum rich. Which will cause the engine to drown in fuel on the over-run. Some installs (particularly on the P38 which uses 5-0V lambda sensors which aren't compatible with a lot of LPG systems) have a lambda sensor fitted purely to drive the LPG system but if you don't have any at all, then you need one fitting in one or other downpipe. Unless, as Simon is hinting at, the actuator has been replaced with a manual valve in which case you are running an open loop system and the Tec99 is doing nothing more than switching fuels. If it is configured as an open loop system with a manual valve then we are into screwdriver tweaking territory see http://www.diy-lpg.co.uk/articles/files ... -loop.html.

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'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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PostPosted: Wed Nov 16, 2016 1:41 pm 
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Although it is possible to set up most closed loop single point systems including Tec99 so that the control valve's working range is restricted. If that range is entirely restricted then it acts like a manually adjustable control valve (stuck in one position) except it's position is controlled via ECU settings rather than manually. However, in this scenario the electronic valve might as well be replaced with a manual valve, there's nothing to go wrong in a manual valve while the electronic valve will wear out eventually (even fixed in one position) because every time the engine stops running or is switched to petrol the electronic valve fully closes (fixed in one position after engine is switched to gas for the duration of running on gas).

Did you buy this car with the system fitted or have you removed the system from another vehicle and fitted it yourself, etc? How well has it run on gas in the past?

Simon

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PostPosted: Wed Nov 16, 2016 7:22 pm 
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LPGC wrote:
Wouldn't be much point of a closed loop system like Tec99 without a lambda sensor.

In the gas pipe between the reducer and mixer there will be a flow control valve, is this electronic (as in wires to it) or just a manual adjuster?

Simon

it is electric simon

ive only had the RR for about 5 months and its been running very well this problem is not all the time I did buy it with lpg
how would this manual valve work and would it be worth getting hold of one.
ive got to know a mate in my local landy club who works on forklifts with gas and seem to have good knowledge
and may be able to help with it possibly
thanks andy


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PostPosted: Wed Nov 16, 2016 8:41 pm 
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Its possible to have welded a boss into the exhaust to screw a lambda sensor into it - Given you have an electronic ecu which would expect an input, are you sure there isn't one there anywhere? Even if the base vehicle doesn't need/have one.

If you follow the pipe between the reducer and where it joins the inlet manifold somewhere along that run you should have the valve - does it have wires to it?

It might speed up some assistance if you can post some photos - theres a sticky topic at the top of the board about doing so as you won't be able to attach them.


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PostPosted: Wed Nov 16, 2016 11:11 pm 
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As Simon says, it's possible to restrict the range on the actuator but to do that you need the cable and software which you don't have. Replacing the actuator with a manual valve would be a better option if you don't have a lambda sensor although the reason why the lambda controlled systems came about is that the mixture will vary quite a bit on a manual system. The difference between a clean and dirty air filter, hot weather and the middle of winter, even atmospheric pressure will all alter the mixture. A lambda system will fine tune so it stays in tune all the time. What year is the Classic as if it was fitted with cats when new it must have them fitted for the MoT test. They became compulsory from around '91.

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'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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PostPosted: Thu Nov 17, 2016 6:43 am 
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It's a 1990 3.9efi
I will look into trying to get pictures on
Andy


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PostPosted: Thu Nov 17, 2016 4:47 pm 
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Agreed with Brian and Gilbert.

If there is no lambda boss in the manifold then would expect the Tec99 to be set up so that the electronic valve is limited to one position (as suggested above). If there is a lambda probe fitted then would expect the Tec99 to be set up in the normal way (where Tec99 adjusts the electronic valve). A duff lambda that is only used by the LPG system, not the petrol system (and this will be the case on a vehicle that left the factory without lambdas fitted) would only affect running on LPG - So in this case I'd check such lambda was working properly at an early stage. One check (with potential to be conclusive as to whether the probe works properly or not) would involve the multimeter as mentioned above while running on petrol - the voltage should be seen to change at least a bit during different driving conditions and should go high when driven flat out.

Not related to solving the problem discussed on this thread but relavent to general topic - A few times lately I've said 'thought about this before' on forum and here's another case of that, this is directed at Gilbert (as RangeRover enthusiast also into electronics)... I believe voltage dividers (resistors) fitted under the dash on Classics are there to emulate a constant lambda neutral signal(?) On these models, if an actual lambda is retro fitted, could bits under dash be removed and lambdas wired in to effect closed loop operation on petrol?

Simon

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PostPosted: Thu Nov 17, 2016 11:28 pm 
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No, the tune resistors are there on a 14CUX ECU to tell it what fuel map it should be using. They have 4 options, Australia and rest of world (180 Ohms), UK and Europe non cat (470 Ohms), Saudi non cat (910 Ohms) and Europe cat (3k9 Ohms). So if you de-cat a Classic the tune resistor needs to be changed to the non cat value. Unless you de-cat but leave the lambda sensors in place, in which case you wouldn't need to do anything.

However, in the case of the one being talked about here, a 1990 EFi would be running the 14CUX ECU with cats and the tune resistor as long as it is a 1990 model. Cats and lambda sensors were fitted from 1987 onwards (so a de-catted 1990 should be an automatic MoT fail) but a 1989 model, which a car first registered in 1990 could well be, used the earlier 14CU ECU with no tune resistor, but a different model ECU for the differing specs. So with no cats or lambda sensors it's going to be wrong on petrol anyway.

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'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.


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PostPosted: Fri Nov 18, 2016 8:02 pm 
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Ahh thanks Gilbert. Interesting that the map can be changed that way.

Simon

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