V8 LPG

Our Discovery runs on LPG most of time, we tend to do a few miles on petrol
when we run out. But now on petrol it runs really rough, feels like its
going to stall when on tick over (its fine on gas). I was wondering if the
injectors get clogged if they arent used much?
If so, is it worth putting injector cleaner in the tank or taking them out
and getting them checked/cleaned?
Or does anyone have any other ideas?
Thanks
Richard

On or around Sun, 07 Nov 2004 16:40:29 GMT, "Richard" <richardsemail
[email protected]> enlightened us thusly:

>Our Discovery runs on LPG most of time, we tend to do a few miles on petrol
>when we run out. But now on petrol it runs really rough, feels like its
>going to stall when on tick over (its fine on gas). I was wondering if the
>injectors get clogged if they arent used much?
>If so, is it worth putting injector cleaner in the tank or taking them out
>and getting them checked/cleaned?
>Or does anyone have any other ideas?

sounds a bit like mine. I think it's a good idea to run it a bit on petrol
every now and then.

mind, there's a funny problem on mine, which means it doesn't run that well
on petrol anyway, also the ignition is advanced on account of the gas, so I
wouldn't expect the petrol to be perfect.

thassa point, any hotwire experts care to inform if there's a
temperature-sensitive enrichment or any such thing on it? 'cos mine seems
to go better when it's cold.

In message <[email protected]>, Richard
<richardsemail@NOSPAM.?.co.uk.invalid> writes
>Our Discovery runs on LPG most of time, we tend to do a few miles on petrol
>when we run out. But now on petrol it runs really rough, feels like its
>going to stall when on tick over (its fine on gas). I was wondering if the
>injectors get clogged if they arent used much?
>If so, is it worth putting injector cleaner in the tank or taking them out
>and getting them checked/cleaned?
>Or does anyone have any other ideas?
>Thanks
>Richard
>
>
It's a possibility - which is why some installers don't use emulators
but stop the petrol pump. If you don't normally use petrol for starting
then it is quite likely that the injectors are clogged. Also you may
have an emulator problem. Is it consistently the same cylinders which
are misfiring - might indicate an emulator problem Your idle speed
control valve would probably show up on gas too. Have you checked your
coolant level in the radiator (not the header tank)?
--
hugh
Reply to address is valid at the time of posting

In <[email protected]> Richard wrote:
> Our Discovery runs on LPG most of time, we tend to do a few miles on
> petrol when we run out. But now on petrol it runs really rough, feels
> like its going to stall when on tick over (its fine on gas). I was
> wondering if the injectors get clogged if they arent used much? If so,
> is it worth putting injector cleaner in the tank or taking them out
> and getting them checked/cleaned? Or does anyone have any other ideas?

The injectors can get blocked or rust/oxidise when running full time LPG
which is a good reason to start on petrol even if your system (like mine)
will start quite happily on LPG. You may also find that your timing has
been set to suit LPG more than petrol which can also make a difference,
especially at tick over.

Getting the injectors cleaned is a major PITA. I got two sets cleaned at
Billing on the stand - I took a set out of my Disco (the Disco stayed at
home) and used my competition motor to go to the show with the caravan
on the back. The competition motor took an hour to strip and about 2
hours to put back together again with the cleaned injectors. The Disco
took an hour to take apart and 6 hours to put back together when I
struggled to get the fuel system fuel tight again and ended up doing the
whole job twice with a trip to Thirsk and back to get some fresh sealing
rings in between.

The results in the competition motor (3.9 auto Defender) were good with
a definite improvement in response and torque. The results in the Disco
weren't noticeable, it still runs rough on petrol :-( I'd certainly give
some injector cleaner in the tank a go. With any hotwire system it's
always worth changing the EFi coolant temperature sender just to see...
they are cheap and easy enough to replace and have a huge bearing on the
fuelling under all conditions. It's located at the front left of the
engine, just behind the distributor (if you have one).

cheers

Dave W.
http://www.yorkshireoffroadclub.net/

In <[email protected]> Austin Shackles wrote:
> thassa point, any hotwire experts care to inform if there's a
> temperature-sensitive enrichment or any such thing on it? 'cos mine
> seems to go better when it's cold.

There is a thermistor located at the front left of the engine (just
behind the distributor) that the ECU uses for the engine coolant
temperature. This temperature input is used to shift the fuelling map up
or down to compensate for the engine's temperature. It is so simple to
replace (a couple of minutes) and so cheap to buy from Land Rover that
it's hardly worth trying to test it. Note that this is not the same
temperature sender that the temperature gauge in the dash uses. It has a
connector on to the top of it that is the same as the injector
connectors.

There is also a fuel rail temperature sender but I've not known one of
these to cause a problem. It's also worth checking/adjusting the MAF
meter as, when not running in closed loop with lambda sensors, the
primary fuelling information comes from the MAF meter (measuring the
quantity and mass/density of the air going into the engine) and the
engine and fuel temperature which allows it to compensate for cool
running/starting and high or low fuel temperature which effects the
density and hence the quantity of fuel. The only other important input
is the throttle position from the throttle potentiometer but that is
used more for transitions than constant revs.

Don't know if that makes any sense but in summary, change the
temperature sender and see if that helps

cheers

Dave W.
http://www.yorkshireoffroadclub.net/

On or around Sun, 7 Nov 2004 22:34:54 +0000 (UTC), Dave White
<[email protected]> enlightened us thusly:

>In <[email protected]> Austin Shackles wrote:
>> thassa point, any hotwire experts care to inform if there's a
>> temperature-sensitive enrichment or any such thing on it? 'cos mine
>> seems to go better when it's cold.
>
>There is a thermistor located at the front left of the engine (just
>behind the distributor) that the ECU uses for the engine coolant
>temperature.

OK. I'll have a look.

> It's also worth checking/adjusting the MAF
>meter as, when not running in closed loop with lambda sensors, the
>primary fuelling information comes from the MAF meter (measuring the
>quantity and mass/density of the air going into the engine) and the
>engine and fuel temperature which allows it to compensate for cool
>running/starting and high or low fuel temperature which effects the
>density and hence the quantity of fuel. The only other important input
>is the throttle position from the throttle potentiometer but that is
>used more for transitions than constant revs.

the MAF was adjusted, sometime after I got it. Basically, it runs nicely at
whatever speed it's doing but it's not so good at small variations of speed
mid-throttle, and mid-revs. get the revs over 3000 at high throttle opening
and it goes pretty well - applying a bit more throttle at say 1800 revs
makes not much difference, or not as much as I'd expect.

might just be a tired cam, at that, I've not looked, and it has done about
97K miles now.

Hi mine disco has just starerd to get the same problem have used the
injector cleaner has helped .I am taking mine to the man that does mw
work on the car so when i know what the problem is i will post it to
you

On Sun, 07 Nov 2004 16:40:29 GMT, "Richard" <richardsemail
[email protected]> wrote:

>Our Discovery runs on LPG most of time, we tend to do a few miles on petrol
>when we run out. But now on petrol it runs really rough, feels like its
>going to stall when on tick over (its fine on gas). I was wondering if the
>injectors get clogged if they arent used much?
>If so, is it worth putting injector cleaner in the tank or taking them out
>and getting them checked/cleaned?
>Or does anyone have any other ideas?
>Thanks
>Richard
>

I have changed the coolant temp sensor (not the one for the gauge, the other
one), it has been on a diagnostic computer and it was all ok. I have checked
the coolant level in the header tank and it was down about an inch, I havent
checked the rad level yet, would this be any differant ? If so, how does it
make it run rough ?
Richard



<[email protected]> wrote in message
news:[email protected]...
> Hi mine disco has just starerd to get the same problem have used the
> injector cleaner has helped .I am taking mine to the man that does mw
> work on the car so when i know what the problem is i will post it to
> you
>
> On Sun, 07 Nov 2004 16:40:29 GMT, "Richard" <richardsemail
> [email protected]> wrote:
>
>>Our Discovery runs on LPG most of time, we tend to do a few miles on
>>petrol
>>when we run out. But now on petrol it runs really rough, feels like its
>>going to stall when on tick over (its fine on gas). I was wondering if the
>>injectors get clogged if they arent used much?
>>If so, is it worth putting injector cleaner in the tank or taking them out
>>and getting them checked/cleaned?
>>Or does anyone have any other ideas?
>>Thanks
>>Richard
>>
>