"Check Engine" on LPG'ed Rover 75 2.0 V6

[Garethsd1]

Hi everyone

Although my car seems to run perfectly on LPG and has done for the last 3 months since the conversion, in the last few weeks the "Check Engine" light has come on 3 times now.

Each time it's come on has been within the first 5-10 minutes after the car has switched to LPG from cold with the engine still warming up.

The first time it happened I lived with the light on for a few days until the garage could fit me in and they cleared the fault codes manually (it had just had the 2000 mile "bedding in" checks a week earlier so we assumed it was still bedding in). Although emissions and injector timings were fine, he enriched the mixture a tad and agreed to suck it and see.

The second time (last Monday and within 40 miles of the fault being cleared), I was driving to a holiday so lived with the light on for a couple of days -until it went out of its own accord on Friday (though I'd run out of gas by then and was back on petrol).

However, it's come on again this morning not long after the engine was started up and switched over to gas. Within about 50 metres of my garage!

The LPG convertor, to his credit, is interested in helping me out and he thinks that the mixture may be too weak or too rich for a period after switch over - unfortunately, his Diagnostic Checker can only clear, not capture, fault codes so we can't see what exactly the fault is.

From experience, is there anything obvious that may be causing this? We changed the spark plugs during the conversion so they're nearly new and it ran fine for the first 2000 odd miles. To be fair, it runs very smoothly now too, no discernable loss of power, no hiccups, no backfires, just a sudden urge to throw up the warning light...

Having said that, the car is a little "throaty/raspy" at 3000 rpm and I honestly can't remember if it used to do that - does it on both petrol and gas.

Cheers

Gareth

[Roverron]

Originally Posted by Garethsd1

Hi everyone

Although my car seems to run perfectly on LPG and has done for the last 3 months since the conversion, in the last few weeks the "Check Engine" light has come on 3 times now.

Each time it's come on has been within the first 5-10 minutes after the car has switched to LPG from cold with the engine still warming up.

The first time it happened I lived with the light on for a few days until the garage could fit me in and they cleared the fault codes manually (it had just had the 2000 mile "bedding in" checks a week earlier so we assumed it was still bedding in). Although emissions and injector timings were fine, he enriched the mixture a tad and agreed to suck it and see.

The second time (last Monday and within 40 miles of the fault being cleared), I was driving to a holiday so lived with the light on for a couple of days -until it went out of its own accord on Friday (though I'd run out of gas by then and was back on petrol).

However, it's come on again this morning not long after the engine was started up and switched over to gas. Within about 50 metres of my garage!

The LPG convertor, to his credit, is interested in helping me out and he thinks that the mixture may be too weak or too rich for a period after switch over - unfortunately, his Diagnostic Checker can only clear, not capture, fault codes so we can't see what exactly the fault is.

From experience, is there anything obvious that may be causing this? We changed the spark plugs during the conversion so they're nearly new and it ran fine for the first 2000 odd miles. To be fair, it runs very smoothly now too, no discernable loss of power, no hiccups, no backfires, just a sudden urge to throw up the warning light...

Having said that, the car is a little "throaty/raspy" at 3000 rpm and I honestly can't remember if it used to do that - does it on both petrol and gas.

Cheers

Gareth

I replied to your pm re code readers.

Possibly your lambda sensor is borderline and the weaker lpg is causing it to produce an incorrect signal. The garage should have been able to tell you the code.

Ron

[Garethsd1]

Thanks Ron

Initial thoughts now is to get the fault cleared (it's annoying if nothing else!) and run it on petrol only for a week or so and see if it comes back.

That should help determine if it's an LPG issue or "fair wear and tear".

I'll invest in a code reader too as it should pay for itself over time.

Regards

Gareth

Originally Posted by Roverron

I replied to your pm re code readers.

Possibly your lambda sensor is borderline and the weaker lpg is causing it to produce an incorrect signal. The garage should have been able to tell you the code.

Ron

[Roverron]

Originally Posted by Garethsd1

Thanks Ron

Initial thoughts now is to get the fault cleared (it's annoying if nothing else!) and run it on petrol only for a week or so and see if it comes back.

That should help determine if it's an LPG issue or "fair wear and tear".

I'll invest in a code reader too as it should pay for itself over time.

Regards

Gareth

A code reader is a very handy piece of kit and for £99 could pay for itself after a couple of uses compared to paying a garage to do it.

[Bernard LPG]

I think that you have been trying to PM me (my PM box was full)

Frankly, the guy is not much of a convertor if he cannot read what is going on with fuel trims etc. How on earth did he set it up in the first place?

Not uncommon in the business I'm sorry to say. I've lost count years ago of the times that I've seen systems that have never been set up correctly.

The LPG has obviously not been set up correctly. What make is the LPG system?

[Garethsd1]

Hi Bernard

Yes I did try to pm you!

It's a Zavoli system. Are you based in Evesham? That's not too far from me.

[Bernard LPG]

Originally Posted by Garethsd1

Hi Bernard

Yes I did try to pm you!

It's a Zavoli system. Are you based in Evesham? That's not too far from me.

I used to fit Zavoli.

I'm about 50 miles from you and I've had a couple of customers in the past from Wantage.

If you want to have a ride out, I'll have a look at it for you. No promises, no fees or anything.