Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: dan-eboy on 04 February 2012, 20:12:15

Title: 2.5 V6 ECU?
Post by: dan-eboy on 04 February 2012, 20:12:15
Hi, I'm gonna order a 2nd hand ecu from ebay, it's for a 2.5 V6 manual, does it matter if the ecu is for manual or auto? Thanks
Title: Re: 2.5 V6 ECU?
Post by: albitz on 04 February 2012, 21:31:38
Why are you buying an ECU ?
If you need to buy one,how much are you paying for it ? I dont have one myself but someone else on here might have one,if you need one. ;)
I dont think it matters if the car is auto/manual,but Im not certain, so best to wait for someone who is sure to reply. :y
Title: Re: 2.5 V6 ECU?
Post by: I_want_an_Omega on 04 February 2012, 21:47:15
It doesn't matter, but should be from the same age, i.e. model year. It MUST have the immobiliser ECU as well and chip(s) from the key.

I've got a set available with a single key chip if you are interested.
Title: Re: 2.5 V6 ECU?
Post by: Omega_Dan on 04 February 2012, 21:50:29
I have one off my 2.5. Always worth checking on here. Best place :y
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 04 February 2012, 21:55:15
I was looking at one on ebay which is £25 inc delivery, but it is for a 2000 model and mine is a 95 (N reg).

I'll difinateley buy from someone here if it's not too much more money, thrown too much at this car as it is!  How much and what is the immobiliser ecu and chips? is it all i'll need?  THanks guys
Title: Re: 2.5 V6 ECU?
Post by: Omega_Dan on 04 February 2012, 21:59:32
If you pm Robert as he offered first im sure he will help you Dan. :y
Title: Re: 2.5 V6 ECU?
Post by: I_want_an_Omega on 04 February 2012, 22:05:59
Mine is from a '99. Was the £25 with the immobiliser ECU and key chip?
Title: Re: 2.5 V6 ECU?
Post by: albitz on 04 February 2012, 22:07:09
But why do you think you need one ? They rarely go wrong afaik.
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 04 February 2012, 22:17:28
Well i have a misfire, i've changed leads, plugs twice and dis-pack twice, (non-genuine the first time).  Today i checked the leads and they seem fine so the only thing i'm thinking it could be is ecu or broken/dodgy wire from ecu? It seems to be mis-firing on 3 and 6 and only fault code was 21 for TPS.
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 04 February 2012, 22:18:11
Oh and i think £25 was just ecu, what is the chip etc for?
Title: Re: 2.5 V6 ECU?
Post by: Omega_Dan on 04 February 2012, 22:30:42
The chip goes in the key and the immobilser ecu is linked to the ecu which reads the key on start up. Immobilser ecu is fitted on the ignition in the steering coloum :y
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 04 February 2012, 22:40:31
Not just a case of un-plug, plug-in then! nothings ever easy!  Can you put the chip in the key yourself or is it a main dealer job?  will it not work with just the main ECU then?

Also I was thinking is it possible to check the input to the coil pack, If i use a multimeter on the wires, theres 4 wires i think, so i would guess it would be earth, and 3 sets of leads (1/4, 2/5, 3/6) So if i get 1 wire with low/no voltage i Know it's a prob between ecu and coil, If i test either end of wires i can see if the prob is from the ECU or between ecu and coil, if that makes sense.  Thanks for replies much appreciated
Title: Re: 2.5 V6 ECU?
Post by: I_want_an_Omega on 05 February 2012, 15:21:08
It is simple enough to change:

1) Disconnect battery
2) Swap main ECU
3) Swap immobliser ECU (in steering column)
4) Swap key chip
5) Reconnect battery

They MUST be swapped as a set as they are all coded together
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 05 February 2012, 15:28:10
Thanks, PM sent, hopefully this is the problem if not i might find a large tree to drive into!
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 05 February 2012, 18:11:27
Not sure if this is connected to my other problems but the cars been really struggling to start on these cold mornings.  I turn it over for about 5 seconds, stop, do it again, then on the 3rd time it slowly comes to life. Any ideas what it could be?
Title: Re: 2.5 V6 ECU?
Post by: Omega_Dan on 05 February 2012, 19:19:35
Not sure if this is connected to my other problems but the cars been really struggling to start on these cold mornings.  I turn it over for about 5 seconds, stop, do it again, then on the 3rd time it slowly comes to life. Any ideas what it could be?


Possibly the crank sensor? ;)
Title: Re: 2.5 V6 ECU?
Post by: Elite_L0ver on 05 February 2012, 19:35:03
Not sure if this is connected to my other problems but the cars been really struggling to start on these cold mornings.  I turn it over for about 5 seconds, stop, do it again, then on the 3rd time it slowly comes to life. Any ideas what it could be?

Sounds like your starter Motor mite be on way out or have a dogey earth connection somewhere or battery low do a battery test or a drop test on both battery and altonator
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 05 February 2012, 20:46:41
Thanks, why would the crank sensor cause this?  And what voltage should the battery and alternator have, is it 12v and about 14v for the alternator?
Title: Re: 2.5 V6 ECU?
Post by: Elite_L0ver on 05 February 2012, 23:05:35
Thanks, why would the crank sensor cause this?  And what voltage should the battery and alternator have, is it 12v and about 14v for the alternator?

Not sure about crank sensor but

Battery about 12.5v

Altonator about 14.2v ish
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 06 February 2012, 17:57:52
Thanks for the reply i'll go and check them now!
Title: Re: 2.5 V6 ECU?
Post by: The Red Baron on 06 February 2012, 18:05:35
Thanks, why would the crank sensor cause this?  And what voltage should the battery and alternator have, is it 12v and about 14v for the alternator?

Not sure about crank sensor but

Battery about 12.5v

Altonator about 14.2v ish
have a look here. ;)
http://www.omegaowners.com/forum/index.php?topic=90619.0
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 06 February 2012, 19:25:08
Thanks, the alternator is a bit difficult to get to especially in the dark!, But the battery is reading 12.6 volts so can't see it being a problem with the batt or alternator.

Does anyone know where the Earths are?  I have other probs too and wonder if a good cleaning of the earths wouldn't help.  I've had a look with my torch but to no avail!
Title: Re: 2.5 V6 ECU?
Post by: TheBoy on 06 February 2012, 19:44:22
Sorry, just seen this.  Pre 1998 ECUs are Motronic 2.8.1, post 98 are Motronic 2.8.3 (DBW are Motronic 3.1.1).

I, like others, doubt its the ECU.  Very expensive to change parts willy nilly, and can add other faults which cloud the diagnosis.
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 06 February 2012, 20:07:39
Oh well i have an Ecu on the way with ECU, Immobiliser ECU and chip, thanks to Robert, I think it's from a 99, will it work?
Well I've changed plugs, leads and coil, I really don't know what else it could be now? Thanks
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 07 February 2012, 18:32:50
WOOOHOOO!  :)  The car is now running properly - Despite many people saying 'i doubt it's the coil pack' I changed it and hey presto!  So pleased , thanks everyone for their advice and big thanks to Lincs Robert for the cheap ECU.  Only thing is now one of the instrument panel lights (right side) has gone so can't see how much fuel i have when it's dark!  Prob just a fuse popped when i plugged battery back in ill look in the daylight tomorrow.  Thanks All  :y
Title: Re: 2.5 V6 ECU?
Post by: omega3000 on 07 February 2012, 18:41:22
WOOOHOOO!  :)  The car is now running properly - Despite many people saying 'i doubt it's the coil pack' I changed it and hey presto!  So pleased , thanks everyone for their advice and big thanks to Lincs Robert for the cheap ECU.  Only thing is now one of the instrument panel lights (right side) has gone so can't see how much fuel i have when it's dark!  Prob just a fuse popped when i plugged battery back in ill look in the daylight tomorrow.  Thanks All  :y

Nice one , glad you got it sorted in the end  :y
Title: Re: 2.5 V6 ECU?
Post by: TheBoy on 07 February 2012, 18:49:38
WOOOHOOO!  :)  The car is now running properly - Despite many people saying 'i doubt it's the coil pack' I changed it and hey presto!  So pleased , thanks everyone for their advice and big thanks to Lincs Robert for the cheap ECU.  Only thing is now one of the instrument panel lights (right side) has gone so can't see how much fuel i have when it's dark!  Prob just a fuse popped when i plugged battery back in ill look in the daylight tomorrow.  Thanks All  :y
Blown bulb ;)


As to ecu fixing, see if the running goes rough in a few days/weeks.  Given the haphazard diags, I wouldn't be surprised if the ECU BLMs were well out, rather than an ECU fault.  If there is still an underlying problem, the BLMs will drift again.
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 07 February 2012, 18:53:08
What are BLM's? Is it easy to change the bulb or is it a dash out jobbie?
Title: Re: 2.5 V6 ECU?
Post by: TheBoy on 07 February 2012, 18:56:56
What are BLM's? Is it easy to change the bulb or is it a dash out jobbie?
Block Learns. Basically, the ECU constantly tweaks itself for your specific engine characteristics, and stores the tweaks. Over simplification, but you get the idea.

Dash out. Only 5 min job. Replace all the illumination bulbs together, as chances are another will blow as you disturb it all. Unless you really like the job :P
Title: Re: 2.5 V6 ECU?
Post by: dan-eboy on 07 February 2012, 19:02:45
Cheers mate ill replace them all -spent enough time messing with cars this last month!  The old ECU did have corrosion on about 6 of the lower pins and i think some had almost joined together which might of been shorting it out.  I forgot to take a pic but i will tomorrow so people can see.  :y