Oscillating idle speed

K

krusty1977

New Member

Posts

28

• Feb 22, 2009

• #1

I have a 1990 range rover 3.9 auto. It was converted to LPG several years ago and has been very reliable. I believe it is a Leonardo system???

It has always had an oscillation in the idle speed when running on gas. It oscillates between 700 and 1300 rpms. It doesn't do this when running on petrol.

It also revs up to about 2000rpm on startup and takes about 5 -10 secs to return to idle.

I was told that it could be the stepper motor which i've replaced and it's still the same.

This isn't a major problem but would like to get to the bottom of it. Any help would be much appreciated.

Cheers

 

G

gavbriggs

Well-Known Member

Posts

5,861

Location

Sheffield uk

• Feb 22, 2009

• #2

you could get the software and cable and have a fiddle with the trim settings!

 

K

krusty1977

New Member

Posts

28

• Feb 23, 2009

• #3

Where would I get them from?

 

classic kev

Well-Known Member

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3,517

Location

on the side of a hill near Nannerch, N.Wales

• Feb 23, 2009

• #4

Sounds like you might have a slight air leak somewhere on the induction side. Would suggest strip plenum, clean everything, check all vacuum hoses and re-assemble. Check throttle pot as well.

As for the gas side of things, you'll 'av t'ask somebody else coz i know b all 'bout that.

 

G

gavbriggs

Well-Known Member

Posts

5,861

Location

Sheffield uk

• Feb 23, 2009

• #5

here's the aeb leonardo site (use this for the 175)you will need to id the leo box first tho! and the cable you will need, well search ebay or give me a couple of days and i can tell you what parts you need to build one. mines in my car in storage at moment!!. and obviously a laptop or loooooooonnnnnngggggg lead

 

K

krusty1977

New Member

Posts

28

• Feb 24, 2009

• #6

classic kev said:

Sounds like you might have a slight air leak somewhere on the induction side. Would suggest strip plenum, clean everything, check all vacuum hoses and re-assemble. Check throttle pot as well.

As for the gas side of things, you'll 'av t'ask somebody else coz i know b all 'bout that.

Click to expand...

Thanks for the info.

Had a bit of a fiddle last night and noticed that the Distributor Vacuum unit is a bit loose. Could this affect it?

 

K

krusty1977

New Member

Posts

28

• Feb 24, 2009

• #7

gavbriggs said:

here's the aeb leonardo site (use this for the 175)you will need to id the leo box first tho! and the cable you will need, well search ebay or give me a couple of days and i can tell you what parts you need to build one. mines in my car in storage at moment!!. and obviously a laptop or loooooooonnnnnngggggg lead

Click to expand...

Had a look last night and it is the 175 that i've got, it's about 7 years old. Can you advise on locating a cable and software? Can't see anything on ebay.

Thanks.