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Omega Help Area => Omega General Help => Topic started by: dbr on 04 January 2011, 20:31:41

Title: slight misfire.. then TC light came on
Post by: dbr on 04 January 2011, 20:31:41
Any ideas what might cause? Also, engine racing shortly after starting. (air leak?)
thanks
Title: Re: slight misfire.. then TC light came on
Post by: hotel21 on 04 January 2011, 20:58:43
Traction Control light or (more likely) engine management light?

Probably best to read the codes first.  Check the maintenance guides for a howtoo....   :y
Title: Re: slight misfire.. then TC light came on
Post by: dbr on 04 January 2011, 23:49:33
Quote
Traction Control light or (more likely) engine management light?

Probably best to read the codes first.  Check the maintenance guides for a howtoo....   :y

def TC light... at restart went off but would not turn off via button
Title: Re: slight misfire.. then TC light came on
Post by: Broomies Mate on 05 January 2011, 00:02:31
When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
Title: Re: slight misfire.. then TC light came on
Post by: dbr on 05 January 2011, 00:15:13
Quote
When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
about 2000rpm for may be 20 /30 sec
Title: Re: slight misfire.. then TC light came on
Post by: Broomies Mate on 05 January 2011, 00:19:47
Quote
Quote
When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
about 2000rpm for may be 20 /30 sec

Could be a list of potentialy coincidental things.

Racing engine on start-up could be a vacuum leak, blocked SAI etc etc.

No codes stored I take it?

Oh, when you start from cold, after 10 or 15 seconds, kick the throttle and see if that calms the idle speed.
Title: Re: slight misfire.. then TC light came on
Post by: dbr on 05 January 2011, 00:39:47
Quote
Quote
Quote
When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
about 2000rpm for may be 20 /30 sec

Could be a list of potentialy coincidental things.

Racing engine on start-up could be a vacuum leak, blocked SAI etc etc.

No codes stored I take it?

Oh, when you start from cold, after 10 or 15 seconds, kick the throttle and see if that calms the idle speed.
me driving rather than mrs..... you can get the revs down byb kicking throttle.  still leaves the misfire any link
Title: Re: slight misfire.. then TC light came on
Post by: dbr on 05 January 2011, 00:42:43
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Quote
Quote
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When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
about 2000rpm for may be 20 /30 sec

Could be a list of potentialy coincidental things.

Racing engine on start-up could be a vacuum leak, blocked SAI etc etc.

No codes stored I take it?

Oh, when you start from cold, after 10 or 15 seconds, kick the throttle and see if that calms the idle speed.
me driving rather than mrs..... you can get the revs down byb kicking throttle.  still leaves the misfire any link
another thought... i used to hear a mates sai pump squeal... i have never heard mine make any noise in 11 yrs....can i do an easy test?
Title: Re: slight misfire.. then TC light came on
Post by: dbr on 05 January 2011, 00:45:10
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Quote
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When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
about 2000rpm for may be 20 /30 sec

Could be a list of potentialy coincidental things.

Racing engine on start-up could be a vacuum leak, blocked SAI etc etc.

No codes stored I take it?

Oh, when you start from cold, after 10 or 15 seconds, kick the throttle and see if that calms the idle speed.
me driving rather than mrs..... you can get the revs down byb kicking throttle.  still leaves the misfire any link
another thought... i used to hear a mates sai pump squeal... i have never heard mine make any noise in 11 yrs....can i do an easy test?
also....As yet I have not tested for codes...mot due pal has a garage n code reader.
Title: Re: slight misfire.. then TC light came on
Post by: Broomies Mate on 05 January 2011, 00:46:49
Quote
Quote
Quote
Quote
When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
about 2000rpm for may be 20 /30 sec

Could be a list of potentialy coincidental things.

Racing engine on start-up could be a vacuum leak, blocked SAI etc etc.

No codes stored I take it?

Oh, when you start from cold, after 10 or 15 seconds, kick the throttle and see if that calms the idle speed.
me driving rather than mrs..... you can get the revs down byb kicking throttle.  still leaves the misfire any link

Unfortunately no, but due to recent weather conditions and frost/snow on the windscreen, I'd say the misfire is due to a muntered DISPack (water running straight through the scuttle into your electrical part).

It's not the easiest job in the world to check ALL of the plugs, but pull each one out in turn and check the colour of them.  A misfiring cylinder will normally show a badly coloured plug. (Spark Plugs)

Obviously check for oil/water in the plug wells.

If you have slim hands, reach around the back of the engine, slightly on the passenger side where you will find the DISPack.  You cant see much, but make sure this is a smooth creature without any sharp edges.  Anything sharp there means the DISPack has failed due to water ingress.  I'll add that they can sometimes fail without rusting through.
Title: Re: slight misfire.. then TC light came on
Post by: Broomies Mate on 05 January 2011, 00:48:04
Quote
Quote
Quote
Quote
Quote
When the TC kicks in, the engine only fires on 4 cylinders, giving the impression of a misfire.

I'd suggest a possible fault with the ABS ECU.

When you say the engine is racing, how many RPM?  How long before this returns to normal?
about 2000rpm for may be 20 /30 sec

Could be a list of potentialy coincidental things.

Racing engine on start-up could be a vacuum leak, blocked SAI etc etc.

No codes stored I take it?

Oh, when you start from cold, after 10 or 15 seconds, kick the throttle and see if that calms the idle speed.
me driving rather than mrs..... you can get the revs down byb kicking throttle.  still leaves the misfire any link
another thought... i used to hear a mates sai pump squeal... i have never heard mine make any noise in 11 yrs....can i do an easy test?

If no noise from the SAI, then chances are it was disconnected 11 years ago!  ;D

That said, I dont know if ALL V6's had the SAI fitted back then.  Someone will be able to confirm.  :y
Title: Re: slight misfire.. then TC light came on
Post by: dbr on 05 January 2011, 00:54:01
will make inroads at the weekend, i hope...ta so far
Title: Re: slight misfire.. then TC light came on
Post by: Andy B on 05 January 2011, 00:54:13
Quote
....
If no noise from the SAI, then chances are it was disconnected 11 years ago!  ;D

That said, I dont know if ALL V6's had the SAI fitted back then.  Someone will be able to confirm.  :y

Mine has only recently started to become a bit vocal, and mine is 12 this year.  ;)

AFAIK SAI was only dropped when DBW came in with the 2.6 & 3.2 engines.
Title: Re: slight misfire.. then TC light came on
Post by: Chris_H on 05 January 2011, 11:55:12
The ABS unit creates an effective misfire in order to reduce engine power and thus stop wheelspin.

I've not heard of it doing so when it's not supposed to but it might be worth checking the ABS sensors for dirt or damaged cables in case a pulse is going missing and indicating a false lock-up.
Title: Re: slight misfire.. then TC light came on
Post by: dbr on 05 January 2011, 16:58:34
Thanks to all. Will start to check all and get checked for codes.
Title: Re: slight misfire.. then TC light came on
Post by: al brown on 05 January 2011, 22:36:30
Agree with checking the sensors. Mine misfires before the ABS cuts in. It isnt the best ABS in the world, made for safety, not fun.
Al