Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: symes on 02 February 2013, 10:03:03

Title: v6 missfires-possible cure
Post by: symes on 02 February 2013, 10:03:03
as said-had missfire-erratic running NOT plugs+leads IT was my expansion tank=pipe from throttle body to header tank was blocked(inside header tank) - Unblocked header(must fit new one-when I find ir :D)
Miggy now runs sweet again :y :y :y
Title: Re: v6 missfires-possible cure
Post by: Lazydocker on 02 February 2013, 10:34:12
as said-had missfire-erratic running NOT plugs+leads IT was my expansion tank=pipe from throttle body to header tank was blocked(inside header tank) - Unblocked header(must fit new one-when I find ir :D)
Miggy now runs sweet again :y :y :y

Ooh... A bit of throttle icing! Uncommon in this country but does happen, as you have proven :y
Title: Re: v6 missfires-possible cure
Post by: Andy H on 02 February 2013, 10:38:59
Weird. That pipe is there to stop ice forming in the throttle body.

I have had carburetor icing on old cars and motorbikes and it really screws up the running. I had assumed that the Omega would use the air flow meter to calculate the fuel requirement and wouldn't be so badly affected :-\ maybe at small throttle openings it uses the throttle position sensor but gets the fueling wrong because the throttle is bunged up with frost  :-\

[note to self] must type faster! [/note to self]
Title: Re: v6 missfires-possible cure
Post by: Webby the Bear on 02 February 2013, 13:23:19
hi guys,

sorry i'm confused as to what's happened here.

so the coolant pipe from expansion tank to throttle body was blocked not allowing coolant to the throttle (butterflies presumably?) and the butterflies froze???? therefore i suppos the throttle position would have been out compared to the air coming in read by the MAF.

I got that right? lol?

what was it blocked with symes?  :y
Title: Re: v6 missfires-possible cure
Post by: Lazydocker on 02 February 2013, 13:42:37
hi guys,

sorry i'm confused as to what's happened here.

so the coolant pipe from expansion tank to throttle body was blocked not allowing coolant to the throttle (butterflies presumably?) and the butterflies froze???? therefore i suppos the throttle position would have been out compared to the air coming in read by the MAF.

I got that right? lol?

what was it blocked with symes?  :y

To make it short and simple... Google the "Venturi Effect" for more information :y But...

The air, which is mist, accelerates as it passes through the restriction of the throttle bodies. This acceleration (change in pressure) also cools it dramatically and causes the moisture in the air to freeze. This frozen moisture restricts the movement of the throttle bodies :y

That's in very basic, layman's terms... Like I said, google as above or "Carb Icing" for more info :y
Title: Re: v6 missfires-possible cure
Post by: Webby the Bear on 02 February 2013, 13:45:45
hi guys,

sorry i'm confused as to what's happened here.

so the coolant pipe from expansion tank to throttle body was blocked not allowing coolant to the throttle (butterflies presumably?) and the butterflies froze???? therefore i suppos the throttle position would have been out compared to the air coming in read by the MAF.

I got that right? lol?

what was it blocked with symes?  :y

To make it short and simple... Google the "Venturi Effect" for more information :y But...

The air, which is mist, accelerates as it passes through the restriction of the throttle bodies. This acceleration (change in pressure) also cools it dramatically and causes the moisture in the air to freeze. This frozen moisture restricts the movement of the throttle bodies :y

That's in very basic, layman's terms... Like I said, google as above or "Carb Icing" for more info :y

nice one lazy. already done venturis in carbs at school  :y but ill check it out  :y
Title: Re: v6 missfires-possible cure
Post by: Lazydocker on 02 February 2013, 13:48:10
hi guys,

sorry i'm confused as to what's happened here.

so the coolant pipe from expansion tank to throttle body was blocked not allowing coolant to the throttle (butterflies presumably?) and the butterflies froze???? therefore i suppos the throttle position would have been out compared to the air coming in read by the MAF.

I got that right? lol?

what was it blocked with symes?  :y

To make it short and simple... Google the "Venturi Effect" for more information :y But...

The air, which is mist, accelerates as it passes through the restriction of the throttle bodies. This acceleration (change in pressure) also cools it dramatically and causes the moisture in the air to freeze. This frozen moisture restricts the movement of the throttle bodies :y

That's in very basic, layman's terms... Like I said, google as above or "Carb Icing" for more info :y

nice one lazy. already done venturis in carbs at school  :y but ill check it out  :y

So they should have taught you about the cooling of air and the potential for carb icing ;)

To help a little more... Many Light Aircraft still use carbs so carb icing is a real threat for them so you might find a little more detailed information on an aviation site ;)
Title: Re: v6 missfires-possible cure
Post by: Webby the Bear on 02 February 2013, 13:58:58
hi guys,

sorry i'm confused as to what's happened here.

so the coolant pipe from expansion tank to throttle body was blocked not allowing coolant to the throttle (butterflies presumably?) and the butterflies froze???? therefore i suppos the throttle position would have been out compared to the air coming in read by the MAF.

I got that right? lol?

what was it blocked with symes?  :y

To make it short and simple... Google the "Venturi Effect" for more information :y But...

The air, which is mist, accelerates as it passes through the restriction of the throttle bodies. This acceleration (change in pressure) also cools it dramatically and causes the moisture in the air to freeze. This frozen moisture restricts the movement of the throttle bodies :y

That's in very basic, layman's terms... Like I said, google as above or "Carb Icing" for more info :y

nice one lazy. already done venturis in carbs at school  :y but ill check it out  :y

So they should have taught you about the cooling of air and the potential for carb icing ;)

To help a little more... Many Light Aircraft still use carbs so carb icing is a real threat for them so you might find a little more detailed information on an aviation site ;)

nice one  :y ill 'ave a butchers  :y
Title: Re: v6 missfires-possible cure
Post by: Lazydocker on 02 February 2013, 14:00:31
Should add, the reason throttle icing is rare is because you don't have the additional temperature reduction caused by the vaporisation of the fuel, which is quite marked :y
Title: Re: v6 missfires-possible cure
Post by: symes on 02 February 2013, 21:39:07
Dont know about ice freezing it up but honestly miggy was running sick this morning and when I cleared that blockage-ran sweet again ??? ??? Reckon my miggy got mind of its own :o
Title: Re: v6 missfires-possible cure
Post by: Andy H on 02 February 2013, 21:54:50
Carburettor icing is only rare if you don't have carburettors and only drive on warm sunny days >:(

On both my series III Land Rover & my old V8 Range Rover I had fit a means of heating the carburettors in cool/damp weather :( :(

Unleaded petrol seems to be much worse for icing than original full fat 4 star  :-\

Nearly all cars (produced in the last 40 rears)  have had either a thermostatic air intake or a water heated throttle body to prevent icing. Kawasaki had to recall some of their motorbikes & fit electric carburettor heaters when unleaded fuel became common.
Title: Re: v6 missfires-possible cure
Post by: Lazydocker on 02 February 2013, 22:21:14
Carburettor icing is only rare if you don't have carburettors and only drive on warm sunny days >:(

On both my series III Land Rover & my old V8 Range Rover I had fit a means of heating the carburettors in cool/damp weather :( :(

Unleaded petrol seems to be much worse for icing than original full fat 4 star  :-\

Nearly all cars (produced in the last 40 rears)  have had either a thermostatic air intake or a water heated throttle body to prevent icing. Kawasaki had to recall some of their motorbikes & fit electric carburettor heaters when unleaded fuel became common.

True... But then there are very few (if any) modern cars that have carbs ;)
Title: Re: v6 missfires-possible cure
Post by: symes on 02 February 2013, 22:25:24
Carburettor icing is only rare if you don't have carburettors and only drive on warm sunny days >:(

On both my series III Land Rover & my old V8 Range Rover I had fit a means of heating the carburettors in cool/damp weather :( :(

Unleaded petrol seems to be much worse for icing than original full fat 4 star  :-\

Nearly all cars (produced in the last 40 rears)  have had either a thermostatic air intake or a water heated throttle body to prevent icing. Kawasaki had to recall some of their motorbikes & fit electric carburettor heaters when unleaded fuel became common.

True... But then there are very few (if any) modern cars that have carbs ;)
I know mate-as said weird cause/effect though-
Title: Re: v6 missfires-possible cure
Post by: albitz on 02 February 2013, 22:27:56
Drove my Omega today,and it definitely had a misfire and a lack of power on LPG at around 2k rpm.Switched to petrol and it was fine.
Might try changing plug leads as I have a spare set.If that doesnt work, my recently replaced dispack "thought to be a good one but not certain",may be suspect. Other than that - LPG system problem I suppose. :-\
Title: Re: v6 missfires-possible cure
Post by: omega3000 on 02 February 2013, 22:42:59
Carburettor icing is only rare if you don't have carburettors and only drive on warm sunny days >:(

On both my series III Land Rover & my old V8 Range Rover I had fit a means of heating the carburettors in cool/damp weather :( :(

Unleaded petrol seems to be much worse for icing than original full fat 4 star  :-\

Nearly all cars (produced in the last 40 rears)  have had either a thermostatic air intake or a water heated throttle body to prevent icing. Kawasaki had to recall some of their motorbikes & fit electric carburettor heaters when unleaded fuel became common.

Aye , my old Gpz 750 suffered icing but later model got the carb heaters  >:(
Title: Re: v6 missfires-possible cure
Post by: symes on 02 February 2013, 22:47:13
Drove my Omega today,and it definitely had a misfire and a lack of power on LPG at around 2k rpm.Switched to petrol and it was fine.
Might try changing plug leads as I have a spare set.If that doesnt work, my recently replaced dispack "thought to be a good one but not certain",may be suspect. Other than that - LPG system problem I suppose. :-\
Try Denso plugs mate-mine used to faf about until put those in- :y
Title: Re: v6 missfires-possible cure
Post by: Kevin Wood on 02 February 2013, 22:49:42
An additional factor in carb icing is that sometimes fuel has significant moisture in it, which doesn't help.

With an injection setup, the fuel is out of the picture, but given the right weather conditions (low enough temperature and significant humidity) it can still happen, hence the heated throttle body.
Title: Re: v6 missfires-possible cure
Post by: symes on 02 February 2013, 22:54:42
An additional factor in carb icing is that sometimes fuel has significant moisture in it, which doesn't help.

With an injection setup, the fuel is out of the picture, but given the right weather conditions (low enough temperature and significant humidity) it can still happen, hence the heated throttle body.
Well it was cold mate but had me flummoxed for a while-did have a mild worry that the old girl was throwing the towel in-I even promised to clean her nest weekend :D :D-Nuts I know but reckon she got mind of her own mate :D ;D
Title: Re: v6 missfires-possible cure
Post by: albitz on 02 February 2013, 22:56:13
Previously it has always been fine on GM twins.It had new GM twins in the last couple of thousand miles.
Problem started with rusted/split dispack.Changed that for one which looked excellent and was thought to be a good one.So I think its either that or possible the leads. :-\
Title: Re: v6 missfires-possible cure
Post by: Kevin Wood on 03 February 2013, 00:35:14
An additional factor in carb icing is that sometimes fuel has significant moisture in it, which doesn't help.

With an injection setup, the fuel is out of the picture, but given the right weather conditions (low enough temperature and significant humidity) it can still happen, hence the heated throttle body.
Well it was cold mate but had me flummoxed for a while-did have a mild worry that the old girl was throwing the towel in-I even promised to clean her nest weekend :D :D-Nuts I know but reckon she got mind of her own mate :D ;D

Mine gets cleaned when there's nothing else left that needs fixing.. It is fully aware of this policy. So, until that PITA sticky central locking motor has been refurbed... >:(

 ;)