Idle problem

[Vallhund]

Hi, My 'Torslanda' is an LPG conversion and has no probs idling when on Gas but the idle wavers when on Petrol. I have checked all hoses,cleaned the plastic crankcase breather box. I know what the ECU is doing and understand the 'closed loop' cycle. Where else can air get in. The signals from the TPS and Lamda sensor were checked as part of the conversion. Is it me or is the car supposed to idle like such. It wavers by only about 200rpm but i,m wondering if it will affect the emmisions test on the forth comming MOT. And by the way, do they test both fuels on the MOT and will my insurance be affected.

[davew]

I had my MOT done 10 days ago and they only tested on LPG.

I told my insurance company and they didnt add anything. Just sent out a new policy stateing LPG conversion fitted.

[GavinC]

You can specify that they test on one fuel, or the other. I specify LPG 'cos it's my most used fuel...

[peter8315]

i was told if you drive in on lpg then they test it on lpg, my insurance is'nt affected, but its best to let them know.

[Mike B]

Originally Posted by peter8315

i was told if you drive in on lpg then they test it on lpg, my insurance is'nt affected, but its best to let them know.

Hi
Cert need for Ins by Comp`s Tis the Law,
Big smack on rump other.
Regards
Mike B

[capt jack]

I went through this with my V70 conversion. The car should I believe be tested on petrol - I've now had 5 MoTs with my V70, and every time, at three different places, I was told to arrive with the LPG switched off.

You MUST inform the DVLA and your insurance company of the conversion - it's the law. If not you may find yourself in hot water if you have a bump, or are stopped by any occifers of the law. Shopping round I found that some insurers will offer a discount for LPG, as they reckon that LPG drivers are more cost conscious and therefore more careful than petrol-heads! Also, LPG owners tend to keep their cars longer, which again insurers rate as a better risk.

As for the idle, if it's only lumpy on petrol then the fault has to be in a part of the system not used by gas.

Ignition problems are usually accentuated by LPG and hidden by petrol, so I'd suspect the fuel delivery side of things: dirt in the fuel tank or lines, clogged petrol filter, blocked or dodgy petrol injector (or carb if it's not fuel-injected), or a poorly fuel pump relay.

When you say Torslanda is that a 240, 940 or V70 - all three cars were offered as Torsland models at different times?

Cheers

Jack

[GavinC]

The MOT is done on the fuel 'as presented' to the testing station. Or that's my understanding and that has been my experience over several years - so I present it on LPG. Besides, it's the fuel I run on 99% of the time. Notwithstanding that it's my fuel of choice, I could present for test on petrol if I preferred. As I understand it.

If my car were to be failed on petrol but'd pass on LPG - which I use 99% of the time - it'd seem somewhat perverse, wouldn't it? But the law can be an ass... And I accept that it can change or be updated.

Isn't an emissions test more demanding on petrol than on LPG 'cos LPG is so much cleaner?
In which case a tester might prefer to test on petrol. We should have testing stations that are independent of the vested interest of garage workshops... for that very reason I've used my local borough council testing facility at their garage workshop occasionally in the past. Paid full MOT rate but it was worth it.

Having done a google on the subject 'MOT on LPG or petrol' I can't find anything to the contrary. I, and others I am sure, would rather be forearmed rather than be pushed in whatever direction might suit a garage... for whatever reason.

So if anyone can present welcome evidence to the contrary, please tell. eg. Captain Jack?...

[capt jack]

Hi GavinC

My belief is that amongst the reasons you'd have the test done on petrol:

1. Everything is computerised at the test station, and they only have data for cars as per factory spec.

2. Garages are frightened of LPG conversions - they don't have the training / experience / insurance etc, so if the car comes in with the LPG conversion not switched on then they can safely and legitimately ignore it.

3. If the car comes in running on LPG they have to inspect the LPG fuel lines and tank for leaks - see reason 2.

4. LPG burns cleaner than petrol, so if a car passes OK on petrol it'd breeze through on LPG. The tester has to assume worst-case scenario - you can't claim 'I don't run it on petrol' as a car that will pass on LPG might not pass on petrol.

5. MoT testers round here can't @rs@d to do anything other than the most simple!

These may of course all be urban myths, or excuses from ill-informed MoT testers I have known! Interesting that the experience of others differs. Just goes to prove that even in these regulated days, some things are still open to interpretation!

Cheers

Jack

[31satara]

Interestingly I was checking out the DVLA to see what they said about informing them about converting to LPG. I found this:

Change to fuel type

DVLA will need written confirmation of changes to fuel type for vehicles registered after 1 March 2001 if:

your existing engine is converted, the confirmation must be on headed paper from the garage that carried out the work
a new engine is fitted, the receipt will be required as confirmation

The date is very specific, so this suggests to me that you don't have to, by law, inform them as above in writing if registered before then. I assume this is to link in with the road tax...... However, it doesn't state you don't have to inform them at all........

[Vallhund]

I was after a discount from DVLA and they said you get a 15 quid discount for retro fitted kits on vehicles from March 2001. Mine is a '93' Torslanda 240 so no hope there. Although i fitted the kit myself , i bought it from 'Tinytech' so took it back to them to get checked / Certificated . only cost 25 quid as upposed to the 100 quid other people charge. My emmisions on both petrol and gas are well below the thresholds so good news there. I,ll leave it on petrol for the MOT so as not to confuse them. I did find a loose hose on the plastic branch filter above the breather box. As part of the LPG conversion it was stretched to fit the mixer coller. Also it was baked hard also. New length of hose and rerouted over the manifold insted of in between the branches. Still get a 'too' rich/lean code but i can live with that as i know from the emmisions which way it is. As long as i,m not backfiring , im ok. Payback in 20 tanks . 60ltr petrol/78 liter gas and flashlube fitted. DIY kit cost 550 quid + 40 quid for Flashlube.