Omega Owners Forum

Chat Area => General Discussion Area => Topic started by: JamesV6CDX on 03 January 2008, 16:24:50

Title: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 16:24:50
I'm not prepared to 100% say it's sorted, but early indications would show that the idle problems on Gas are now resolved.

Any guesses at what I did?

I'll give you 2 clues:

1) I only identified the potential cause of the LPG idle problem when the car completely died and refused to run.

2) The replacement (upgraded) part cost me just over £35 on trade club.





Title: Re: LPG idle problem - THINK I've cracked it.
Post by: tunnie on 03 January 2008, 16:30:33
HBV
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 16:31:22
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HBV

Nope!

Although (obviously not advisable), the engine will run without a HBV ;)
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Marks DTM Calib on 03 January 2008, 16:32:12
Crank sensor....
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 16:32:21
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HBV

Also don't forget that, as you saw, my evap is fed from the bridge, so no HBV in the area. You're not even "warm" ;D
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 16:32:55
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: VXL V6 on 03 January 2008, 16:33:17
Crank Sensor?

But they are a bit more than that aren't they?

Edit: too slow at posting!
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: VXL V6 on 03 January 2008, 16:34:20
CTS?
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Marks DTM Calib on 03 January 2008, 16:36:10
In which case battery......and if it is then it wont have fixed it coz when the engine is running it should have little effect.
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 16:42:11
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In which case battery......and if it is then it wont have fixed it coz when the engien is runnign it should have little effect.




Yes, the battery failed. Old halfrauds crap anyhow, so I replaced it for a VX Go battery for a 3.0

For a long time, it has been suffering from "flickering" of all lights etc on idle. This is instantly resolved with new battery, and idle is better on both fuels. It used to shudder on "eco" on either fuel - now doesn't.

I agree with what you say, but when I put the new battery on, fired it up from cold, it was absolutely fine on gas.

My reasoning is this. I rekon there is a poor connection in the alternator to battery positive+ cable. This is confirmed by the terminal getting hot and wire looks bad.

So, I rekon the old battery wasn't beefy enough, and giving intermittent power to the Gas ecu (which comes directly off it).

So - I rekon I need a new cable.

Either that - or there may have been a poor LPG + connection which I've corrected by taking the terminal off and back on....

Anyone got a p/n for a new + cable?
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: VXL V6 on 03 January 2008, 16:44:24
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Anyone got a p/n for a new + cable?

Don't you have one on the 3.0 Breaker?

Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Marks DTM Calib on 03 January 2008, 16:44:39
There your are......its not the battery at all....you just have a short term reprieve thanks to having a  nice fully charged battery.

You need to sort out the battery charging to fix it..........so the real cause is alternator and/or connecting cable  :y
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 16:46:10
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There your are......its not the battery at all....you just have a short term reprieve thanks to having a  nice fully charged battery.

You need to sort out the battery charging to fix it..........so the real cause is alternator and/or connecting cable  :y

Ok ok.... maybe I should have said Problem "identified" rather than resolved - but you knew what I meant ;D ;D :y
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 16:50:03
Alternator is almost new, so I'm sure it's the cable. Anyone got any ideas on a price from Vx?
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: tunnie on 03 January 2008, 16:57:32
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P

WTF? MrDTM was wrong???

**makes a note** ;D
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 17:01:20
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Quote
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P

WTF? MrDTM was wrong???

**makes a note** ;D

No, he wasn't wrong - based on the initial information it was the most likely suspect....
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Marks DTM Calib on 03 January 2008, 17:02:03
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P

WTF? MrDTM was wrong???

**makes a note** ;D


Poor fault description.....plus the fact that the item bought is not the solution....  ;D ;D ;D
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 17:03:22
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Quote
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P

WTF? MrDTM was wrong???

**makes a note** ;D


Poor fault description.....plus the fact that the item bought is not the solution....  ;D ;D ;D

Ok ok ok you....

Do you agree that it has helped HIGHLGHT and IDENTIFY the cause of the problem?  ;D ;D
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Marks DTM Calib on 03 January 2008, 17:09:36
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Quote
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P

WTF? MrDTM was wrong???

**makes a note** ;D


Poor fault description.....plus the fact that the item bought is not the solution....  ;D ;D ;D

Ok ok ok you....

Do you agree that it has helped HIGHLGHT and IDENTIFY the cause of the problem?  ;D ;D

I would say its narrowed it down.

Poor battery leads dont cause flickering as they tend to simply have a slightly higher resistance which is reasonably constant....alternators with failed rectifiers can though.....or with poor internal connections (as per maintenance guide).

I would be checking charging voltage with an analogue meter at idle as a next step (fluctuations dont show well on digital ones)

Title: Re: LPG idle problem - THINK I've cracked it.
Post by: cem_devecioglu on 03 January 2008, 17:25:58
Interesting relation..

Though I changed the parts inside the alternator , I'll check the cable and battery also :y

Title: Re: LPG idle problem - THINK I've cracked it.
Post by: TheBoy on 03 January 2008, 19:44:11
I must go and buy a new battery for the MV6 (I knew it was knackered a year ago!), but I just can't face fatty on the parts dept at MK dealer.  And the battery is too heavy to get Mrs TheBoy to pick up from the much better Banbury dealer....
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Kevin Wood on 03 January 2008, 20:11:56
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My reasoning is this. I rekon there is a poor connection in the alternator to battery positive+ cable. This is confirmed by the terminal getting hot and wire looks bad.

Hmm. Battery needed a jolt from the charger before it would start in my garage post-LPG fitting, then the +ve terminal got 'kin hot when it started...

The LPG ECU only read around 12.5v running, too, IIRC.

Can you remake the positive terminal with a new terminal - even as a temporary measure - or is the cable too far gone?

Wobbly battery voltage could explain a few of your LPG troubles I reckon.

Kevin
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 22:08:45
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My reasoning is this. I rekon there is a poor connection in the alternator to battery positive+ cable. This is confirmed by the terminal getting hot and wire looks bad.

Hmm. Battery needed a jolt from the charger before it would start in my garage post-LPG fitting, then the +ve terminal got 'kin hot when it started...

The LPG ECU only read around 12.5v running, too, IIRC.

Can you remake the positive terminal with a new terminal - even as a temporary measure - or is the cable too far gone?

Wobbly battery voltage could explain a few of your LPG troubles I reckon.

Kevin

I agree with all that, Kev. I'll try and fit a new terminal tomorrow.

Failing that, I'll ask the dealer about a new cable, and get the vaseline out ;D

It's definately better since I've fitted the right battery.

The new Vx battery towers over the original - makes it look like it came off a fiesta!!

I also no longer get the dim battery light when heated seats on, since fitting the new battery.

I rekon I'll get away with fitting a new cable, and all will be well  8-) 8-)
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: STMO123 on 03 January 2008, 22:13:00
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My reasoning is this. I rekon there is a poor connection in the alternator to battery positive+ cable. This is confirmed by the terminal getting hot and wire looks bad.

Hmm. Battery needed a jolt from the charger before it would start in my garage post-LPG fitting, then the +ve terminal got 'kin hot when it started...

The LPG ECU only read around 12.5v running, too, IIRC.

Can you remake the positive terminal with a new terminal - even as a temporary measure - or is the cable too far gone?

Wobbly battery voltage could explain a few of your LPG troubles I reckon.

Kevin

I agree with all that, Kev. I'll try and fit a new terminal tomorrow.

Failing that, I'll ask the dealer about a new cable, and get the vaseline out ;D

It's definately better since I've fitted the right battery.

The new Vx battery towers over the original - makes it look like it came off a fiesta!!

I also no longer get the dim battery light when heated seats on, since fitting the new battery.

I rekon I'll get away with fitting a new cable, and all will be well  8-) 8-)

Are they that expensive? ;D
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: x25xe on 03 January 2008, 22:15:58
Did you not post up about the dim alternator warning light with HRW and heated seats switched on before?

It is amazing the difference a decent battery makes though - my car ran much better when I put a new battery on.
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 22:18:48
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Quote
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My reasoning is this. I rekon there is a poor connection in the alternator to battery positive+ cable. This is confirmed by the terminal getting hot and wire looks bad.

Hmm. Battery needed a jolt from the charger before it would start in my garage post-LPG fitting, then the +ve terminal got 'kin hot when it started...

The LPG ECU only read around 12.5v running, too, IIRC.

Can you remake the positive terminal with a new terminal - even as a temporary measure - or is the cable too far gone?

Wobbly battery voltage could explain a few of your LPG troubles I reckon.

Kevin

I agree with all that, Kev. I'll try and fit a new terminal tomorrow.

Failing that, I'll ask the dealer about a new cable, and get the vaseline out ;D

It's definately better since I've fitted the right battery.

The new Vx battery towers over the original - makes it look like it came off a fiesta!!

I also no longer get the dim battery light when heated seats on, since fitting the new battery.

I rekon I'll get away with fitting a new cable, and all will be well  8-) 8-)

Are they that expensive? ;D

Who knows - but this IS Vauxhall!
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Kevin Wood on 03 January 2008, 22:32:17
Check the voltage across the battery at a fast idle with no load on and then with a few loads on and see what's going on.

Also, see if you can get a voltage reading between the positive terminal and the strands of wire going into the crimp connection. Might tell you if you're dropping volts at that connection.

If the terminal is getting hot that's a sure sign that all is not well.

Kevin
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Taxi_Driver on 03 January 2008, 23:10:12
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P

WTF? MrDTM was wrong???

**makes a note** ;D


Poor fault description.....plus the fact that the item bought is not the solution....  ;D ;D ;D

Ok ok ok you....

Do you agree that it has helped HIGHLGHT and IDENTIFY the cause of the problem?  ;D ;D

I would say its narrowed it down.

Poor battery leads dont cause flickering as they tend to simply have a slightly higher resistance which is reasonably constant....alternators with failed rectifiers can though.....or with poor internal connections (as per maintenance guide).

I would be checking charging voltage with an analogue meter at idle as a next step (fluctuations dont show well on digital ones)


I agree with Mark.....it depends what you mean by flickering.....flickering in my book means slightly brighter and dimmer than normal......under no change of load.
For example slight dimming of dash lights at idle in time with indicators going on off with headlinglights on.........would be perfectly normal.
Increasing brightness would not be............
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: JamesV6CDX on 03 January 2008, 23:12:10
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Quote
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Crank sensor....

Nope! Crank sensor is on 110k and is still going strong - I was expecting you to get it first time, Mr DTM :P

WTF? MrDTM was wrong???

**makes a note** ;D


Poor fault description.....plus the fact that the item bought is not the solution....  ;D ;D ;D

Ok ok ok you....

Do you agree that it has helped HIGHLGHT and IDENTIFY the cause of the problem?  ;D ;D

I would say its narrowed it down.

Poor battery leads dont cause flickering as they tend to simply have a slightly higher resistance which is reasonably constant....alternators with failed rectifiers can though.....or with poor internal connections (as per maintenance guide).

I would be checking charging voltage with an analogue meter at idle as a next step (fluctuations dont show well on digital ones)


I agree with Mark.....it depends what you mean by flickering.....flickering in my book means slightly brighter and dimmer than normal......under no change of load.
For example slight dimming of dash lights at idle in time with indicators going on off with headlinglights on.........would be perfectly normal.
Increasing brightness would not be............

I agree with the logic but, after fitting a new battery, all symptoms are gone, incl poor LPG idle, so we're definately barking up the right tree now :y
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Kevin Wood on 04 January 2008, 00:06:04
I guess if the battery was poor, or in a poor state of charge, varying electrical load would cause flickering (in the absence of the full alternator output being available) due to higher internal resistance of the battery, so yes, the battery has cured the flickering for one of those reasons, but I still suspect the root cause is either a dodgy connection at the battery terminal (where the alternator output connects, placing resistance in series with the alternator output) or a problem with the alternator giving poor or fluctuating output.

The positive terminal was suspect when we fitted the LPG so that's the first thing to address IMHO.

Kevin
Title: Re: LPG idle problem - THINK I've cracked it.
Post by: Kevin Wood on 04 January 2008, 00:07:36
Oh, and try to do without the seat heating and all other luxuries until you sort it because I suspect the new battery will end up going the same way as the old one :y

Kevin