Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: vectrolosys on 08 March 2007, 10:29:06

Title: ECM light has come on, plus slight hesitation
Post by: vectrolosys on 08 March 2007, 10:29:06
Hello,

I rarely have problems with my Omega, so rarely need to post, but I wanted to get your opinions on the problem I have started experiencing. I'll be reading off the codes at the weekend, but wanted to know if anyone has had similar experiences.

Looks like I have my first engine management issue. Over the past few weeks, the ECM light has been coming on, and going out again, however, today, when I was driving off when cold, the gearbox was holding in first (as it does (which is correct)) there was a slight hesitation at 3000 RPM, a drop in power and the ECM light came on, normal driving was resumed shortly after.

It has stayed on and not gone off, as it usually does.

I am going to pull the codes off at the weekend, but was wondering if anyone has any ideas to help me along. I floored it from start to just over 5000 RPM, and there was no hesitation at around 4000, which rules out the CAS sensor for me, idle is smooth and lump free, so I am thinking it could be one of the knock sensors. As I say, I'll pull the codes at the weekend and we'll see where we are.

Anyone experienced a similar issue?

Thanks,

James
Title: Re: ECM light has come on, plus slight hesitation
Post by: Marks DTM Calib on 08 March 2007, 10:44:48
The give away on the knock sensors is that the light only comes on when you first take it above about 1800rpm, it then also lacks power....lots of power, it feels like a 4 pot!

Have the cam cover gaskets been done recently or any work around the alternator area....as wire damage is the normal failure condition.

The codes will reveal all.....
Title: Re: ECM light has come on, plus slight hesitation
Post by: vectrolosys on 08 March 2007, 11:51:07
Hello,

I haven't been around the alternator side for a while, though I did clean my breathers again recently. I need to do the drivers side cam cover gasket in the near future, so will probably replace the sensor at the same time as I highly suspect the knock sensor. Funnily enough, it is above 1800 RPM that it drops in power, but then the light comes on and it's happy once more (as it's using a default map I guess). I'll post the codes once I have read them off.

Cheers,

James
Title: Re: ECM light has come on, plus slight hesitation
Post by: TheBoy on 08 March 2007, 17:51:57
Quote
Hello,

I haven't been around the alternator side for a while, though I did clean my breathers again recently. I need to do the drivers side cam cover gasket in the near future, so will probably replace the sensor at the same time as I highly suspect the knock sensor. Funnily enough, it is above 1800 RPM that it drops in power, but then the light comes on and it's happy once more (as it's using a default map I guess). I'll post the codes once I have read them off.

Cheers,

James
Generally, the limp mode for knock sensor is pretty dramatic performance wise.  Its the cable that goes, not sensor, so repairing the cable is easier option if that is the case.

I'm thinking more along lines of emission problem...
Title: Re: ECM light has come on, plus slight hesitation
Post by: vectrolosys on 08 March 2007, 20:09:19
Hello,

Now there you may have a point. Normally, I tend to fill up with Shell V Power, as the car runs very well on this. The other day, I really needed fuel and the nearest outlet was Sainsburys. Their Super Unleaded pump had vanished so I had to fill up with 95 Premium. I live in Bristol, so I am hopefully not affected by the recent Silicon in fuel issues, however, could it be the case that, maybe, because it's supermarket fuel, I have been?

Performance drops off initially, but seems okay once the light is on. If you floor it hard, it will pull with normal vigour......still, as Mark says :), the codes will tell all. Got a price for the knock sensors though from autovaux. £29.99 inc VAT. This is for the earlier style connector which I think my car uses.

Still, I haven't had any fun challenges for a while with the car so this one shall keep me occupied.

James
Title: Re: ECM light has come on, plus slight hesitation
Post by: Redeye on 08 March 2007, 20:20:06

That sounds like my car when the cam sensor went.

 :-?
Title: Re: ECM light has come on, plus slight hesitation
Post by: vectrolosys on 08 March 2007, 20:42:32
Quote
That sounds like my car when the cam sensor went.

 :-?

Thank goodness if it is that, much easier to get to for replacement than the Knock sensors or Lambda probes. I am quite looking forward to the job as I enjoy mechanical challenges :).

James
Title: Re: ECM light has come on, plus slight hesitation
Post by: TheBoy on 09 March 2007, 18:07:43
Quote
Hello,

Now there you may have a point. Normally, I tend to fill up with Shell V Power, as the car runs very well on this. The other day, I really needed fuel and the nearest outlet was Sainsburys. Their Super Unleaded pump had vanished so I had to fill up with 95 Premium. I live in Bristol, so I am hopefully not affected by the recent Silicon in fuel issues, however, could it be the case that, maybe, because it's supermarket fuel, I have been?

Performance drops off initially, but seems okay once the light is on. If you floor it hard, it will pull with normal vigour......still, as Mark says :), the codes will tell all. Got a price for the knock sensors though from autovaux. £29.99 inc VAT. This is for the earlier style connector which I think my car uses.

Still, I haven't had any fun challenges for a while with the car so this one shall keep me occupied.

James
I still have a feeling about emissions....
Title: Re: ECM light has come on, plus slight hesitation
Post by: vectrolosys on 10 March 2007, 11:51:59
Hello,

Codes have been read. They're 21 and 61.

21 - Throttle position sensor (may even resolve my autobox weirdness if I replace this!!)
61 - Fuel Tank vent valve (low voltage) Weird, as I fully cleaned the breathers and unblocked the one for the tank vent valve, maybe this has dug up a previously undiscovered issue.

Still, relatively simple repairs.

James
Title: Re: ECM light has come on, plus slight hesitation
Post by: vectrolosys on 10 March 2007, 12:10:00
Hello,

Faults are cleared for now, I did it a slightly bodge quick way. I removed the two black feed wires from the positive terminal connectors. This cleared the codes.

Both are relatively simple and shall be replaced next service :).

Theboy, you had a point on Emissions!!

Thanks all for your help and opinions.

James
Title: Re: ECM light has come on, plus slight hesitation
Post by: TheBoy on 10 March 2007, 12:19:25
Quote
Hello,

Faults are cleared for now, I did it a slightly bodge quick way. I removed the two black feed wires from the positive terminal connectors. This cleared the codes.

Both are relatively simple and shall be replaced next service :).

Theboy, you had a point on Emissions!!

Thanks all for your help and opinions.

James
It may have cleared the codes, but is the car driving properly now?
Title: Re: ECM light has come on, plus slight hesitation
Post by: vectrolosys on 10 March 2007, 12:56:00
Hello,

Probably not, if the TPS has flagged up a fault, then it must be operating out of range, hence some of the other drivability issues I sometimes experience. I'll be replacing it next weekend, as this is when I plan on carrying out my service, just need to order the bits in.

I am hoping a replacement sensor will change things for the better.

James