idles irraticlly on petrol.

Hi all,
I bought my Gas converted 93 V8i Discovery a few weeks back and I mainly run it on Gas. On Gas it runs and idles well, a little fast sometimes, but nothing too worrying.
Last night I ran out of gas and had to switch over to petrol for quite a while. When I was stuck in traffic I noticed that the engine was idling very irratically and at one point almost stalled it self. Being and automatic I had to change it into neutral and rev it up till the lights changed.

Has anyone else experienced this before? Could it be a possible sensor problem or fuel filter issue? as I don't really know the when this was changed.

Cheers.

might be worth checking your maff sensor as I believe they aren't used when running on gas and when you run low on gas you can get backfires which wreck the snsor.. as I understand it the way to check is to run it on petrol and disconnect the maff sensor. if nothing chnages then the sensor is fubar.. they are easy to replace but not cheap ..

Hi,
Thanks.
But where and what is the maff sensor?

Cheers.

Ah I got you. Air Mass Meter!
I thought the LPG would have needed to use this though?

I don't think so.. wait for the experts to tell me I've got it ass about tit... only the ultra modern multipoint direct injected lpg rigs can use the maff.. anything else just int sophisticated enough to have use for the input

danperrett said:

When I was stuck in traffic I noticed that the engine was idling very irratically and at one point almost stalled it self. Being and automatic I had to change it into neutral and rev it up till the lights changed.

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Is yours carbs or injection? Cause mine was doing exactly the same, I found it was running a little lean so a tweak on the mixture screws and its running beautifully again.

is it "hunting"? mine was so i tightened the accelerator cable up a little, problem sorted.

Mine does the same from time to time but often it's after I've had some issue with running on gas. You running out of gas falls into that category so I would run it on gas and it may well sort it's self out. Sorry I don't know what mechanism is involved.

Also, I've just sorted out a problem on mine. It would struggle to pick up from a stop on gas and the revs would hunt on tickover on petrol. After checking just about everything else I found some plastic trumpet shaped inserts in the throttle body which direct the air flow. They had come adrift and were rattling around in the throttle body inlet, obviously causing erratic airflow. I repositioned them and cleaned the throttle body and it ticks over great now.

I reckon it's probably not the MAF sensor. These seem to be a lot more durable than some people think (unless you fok them up by cleaning them)! If you really suspect the MAF, get it checked electrically is my advice.