Hi everyone,

Sorry if this gets a bit long winded.
I'm in need of some guidance as I have just done the cylinder heads on my 1997 land rover discovery 3.9 V8 EFI and need some help with what I can only think is a regulator of some kind but I'm not sure if it is and where exactly it should be located as I'm fairly certain I didn't take it of and there is no where in the engine to suggest where it may have been. Here are some pics of what I'm talking about.
Thanks in advance Ben.


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Ignore the second pic that was about something else which I've sorted

That is the mixture control valve stepper motor. It might have been replaced with a manual valve. It should be fitted into the rubber hose that goes from the vapouriser to the mixer on the inlet manifold

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There is a screw type valve with a spring on it going to the pipe from the vaporizer to the inlet plenum I will get a picture tomorrow to show what I mean. Which is better a manuel valve or the stepper motor?

Cheers Ben.

For some reason the stepper has probably packed up so someone, rather than fix the fault, has fitted a manual power valve instead. The stepper is controlled by the Leonardo unit and opens and closes to keep the mixture spot on by going on the output of the lambda sensor. They are pretty reliable but can stick or gum up so a good squirt of carb cleaner and/or WD40 is a good idea. You should be able to check if it is working or not fairly easily. When you first turn the ignition on, they usually cycle open then closed. Swapping a stepper for a manual valve is the easiest way of checking to see if a stepper is working so you are already in diagnostic mode anyway! With the engine running, the plunger should be sitting partially open but if you screw in the manual valve to make the mixture weaker, then you should be able to see the plunger opening to attempt to compensate. Open the manual valve to make the mixture richer and you should see the plunger closing to try to correct.

Often, a dead lambda sensor will simply cause the petrol system to simply go into default fuel map but as the Leonardo relies on it, a dead lambda sensor will cause the stepper to try to compensate for something that is wrong in the first place. So checking that the lambda sensor is working correctly is also a good idea. I actually carry a manual power valve in my toolbox so I can always fit it just in case my lambda sensor dies when I'm halfway across Europe!

_________________
'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.

I foolishly gave my power valve away the other week. Chap came in with a jeep on a Leo. Duff stepper motor. I didn't have a spare so I put the valve in, got a new stepper. Bloke never came back. And I didn't even charge him....,

We've probably all done the same, mate! Don't you have a load of manual adjusters knocking about though? At one time you couldn't buy an R90 without getting one in the box and if you fitted a closed loop system you didn't use it... I still have loads knocking about!

Simon
Lpgc

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

Call yourself engineers? I made one from a plastic hosepipe T piece and a seatbelt mounting bolt......

_________________
'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.

I made a 'mixer' from a baked beans can for my 4L Jeep, drove it for about 3000 miles like that including use for towing a large trailer with a Chrysler Grand Voyager on top 400 miles... There was no reason to change it other than it looked untidy, fitted and worked as well as a proper mixer!

Simon
Lpgc

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

Sorry guys been away for the weekend here is that picture I said I would put up.


Where is a good place to get replacement hoses and parts from?
Thanks again Ben.

Yup, the stepper should go in place of that manual valve, assuming it is working. Tinley Tech (http://www.tinleytech.co.uk/acatalog/tt-shop.html) is the best place for bits and pieces. Replacement stepper is on this page http://www.tinleytech.co.uk/acatalog/El ... nents.html about halfway down.

_________________
'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.

Cheers pal. I think I will get a new hose to replace the one that is there for the manual valve so I can keep it spare in the car for just incase. Just need to finish of building the engine back together so I can power her up and test the stepper motor.

One other thing was that a mate of mine has a lubrication bottle in the engine bay that has a hose to the inlet plenum and mine doesn't. Question is should I have one and are they necessary? Sorry for the probably idiot questions but I'm trying to get a better understanding of LPG.
Thanks again Ben.

Not needed on your engine. Your mate will likely have a Japanese or Ford car? The fluid it drips in protects the softer engine valves on vehicles that needs it. Yours doesn't.

Simon
www.Lpgc.co.uk

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

Cheers Simon. My mate has actually got the same engine that's why I asked just for peace of mind.

Range Rover engines don't need it until the Ford/Jaguar engine in the later L322. Anything earlier has got valve seats that are easily hard enough to not. My LSE, had 185,000 miles on the clock when I sold it and the P38 is a couple of miles short of 275,000 at the moment, both having run on LPG for a considerable part of their lives.

Your mate may as well take it off, it's not doing anything.

_________________
'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.

I will let him know. Once again thanks for the advice. I will be testing my stepper motor this weekend hopefully