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[RossMk2]

On some cars this resets the ECU, im sure i read somewhere that this wasnt true on the Omega setup. Im 100% sure that doing this on mine makes a significant difference, so what acctually is unplugging battery & ecu doing?

[rustym95]

not much, but if you leave of for say an hour will wipe codes but not fix the faults it will just come back, but if you fix with bat on faults go any way, thats about it.

[Kevin Wood]

It doesn't clear fault codes on the Omega ECUs IME.

It might well cause the block learning data to return to defaults which means the fuel trims and ICV idle settings will be set to factory defaults so it might be a bit lumpy for a few miles until it has built this information again.

What "significant difference" have you noticed?

Kevin

[MickAP]

Don't know whether the same on the TD.
I removed my ECU without disconnecting the battery.
It was off for a few days, absolutely no problems on refitting it.

Mick

[RossMk2]

It doesn't clear fault codes on the Omega ECUs IME.

It might well cause the block learning data to return to defaults which means the fuel trims and ICV idle settings will be set to factory defaults so it might be a bit lumpy for a few miles until it has built this information again.

What "significant difference" have you noticed?

Kevin

The exact opposite Kevin, it runs like a dream again! The car over time starts to run like tripe, it gradually gets worse week after week then i unplug the battery & ecu, plug them back in and the car is as good as new!

I just wanted to know exactly what it was that what im doing might be affecting so that i can find out whats at fault when its 'learnt' driving information.

[Kevin Wood]

In that case the block learning is taking the settings away from optimum  for some reason. IMHO, could be a poorly Lambda sensor or an exhaust leak / EGR / SAI valve fault causing it to read inaccurately.

Worth checking the rest of the engine management inputs to make sure they are OK too (MAF and coolant temperature, throttle position, etc).

Is it throwing any fault codes or just running rough?

Kevin

[RossMk2]

In that case the block learning is taking the settings away from optimum  for some reason. IMHO, could be a poorly Lambda sensor or an exhaust leak / EGR / SAI valve fault causing it to read inaccurately.

Worth checking the rest of the engine management inputs to make sure they are OK too (MAF and coolant temperature, throttle position, etc).

Is it throwing any fault codes or just running rough?

Kevin

It doesnt throw any faults, it just gradually starts to run rough.

EGR is blocked off and has been since owning the engine with no problems for well over the 1st year of running, had both oxygen sensors replaced, exhaust leak has not been something i have checked, how far back towards the back box would a leak cause these problems? SAI, not clued up on this im afraid, what am i looking for?

Had new CTS, tried 3 different MAF's and have never replaced the TPS. Can the TPS be causing problems without throwing codes?

[Kevin Wood]

An exhaust leak would have to be before the Lambda sensor to make much difference - so manifold & gasket, SAI and downpipe really.


SAI is injection of air into the exhaust manifolds from a blower under the passenger side front wing. If the valve is not closing properly after warm-up it coudl eb that air is getting in here. It can be blanked off and pipework removed as long as the valve remains connected to the ECU.

Had new CTS, tried 3 different MAF's and have never replaced the TPS. Can the TPS be causing problems without throwing codes?

Unlikely, I'd say but it seems you have eliminated (or at least swapped) most things. :-/


Kevin

[RossMk2]

An exhaust leak would have to be before the Lambda sensor to make much difference - so manifold & gasket, SAI and downpipe really.


SAI is injection of air into the exhaust manifolds from a blower under the passenger side front wing. If the valve is not closing properly after warm-up it coudl eb that air is getting in here. It can be blanked off and pipework removed as long as the valve remains connected to the ECU.

Kevin

Anywhere lit. on here where i can go look at the SAI? I need to do some looking up as that may have been removed.

Had new CTS, tried 3 different MAF's and have never replaced the TPS. Can the TPS be causing problems without throwing codes?

Unlikely, I'd say but it seems you have eliminated (or at least swapped) most things. :-/


Kevin

So TPS is pointless messing with!

[Kevin Wood]

Anywhere lit. on here where i can go look at the SAI? I need to do some looking up as that may have been removed.

The SAI system consists of a stainless steel pipe that runs across the front of the cam belt cover between the two exhaust manifolds. It then angles up to a shiny non-return valve body, into rubber hose, through a black plastic valve body and another rubber hose to the blower. I'm sure there's a picture on here somewhere. If it has been removed, check that the inlets to the manifolds have been blocked off well.

So TPS is pointless messing with!

I would have thought so. A Tech 2 session to have a look at the live data might reveal something perhaps? :-/

Kevin

[RossMk2]

Anywhere lit. on here where i can go look at the SAI? I need to do some looking up as that may have been removed.

The SAI system consists of a stainless steel pipe that runs across the front of the cam belt cover between the two exhaust manifolds. It then angles up to a shiny non-return valve body, into rubber hose, through a black plastic valve body and another rubber hose to the blower. I'm sure there's a picture on here somewhere. If it has been removed, check that the inlets to the manifolds have been blocked off well.

Woosh (Straight over ones head) hehe, im pretty sure it has been removed, defo no S/S pipes running round the engine, i'd just need to know more info as to where it should be blocked off so i can check.

So TPS is pointless messing with!

I would have thought so. A Tech 2 session to have a look at the live data might reveal something perhaps? :-/

Kevin

Yeah that is a great idea, i was trying to organize a session with The Boy and his Tech 2 but that kind of fizzled out, he was rather busy at the time.

[Kevin Wood]

Have a look here:

http://www.omegaowners.com/forum/YaBB.pl?num=1189893357



The SAI plumbing can be seen running left to right just under the aux. belt tensioner and you can see the SAI valve in the bottom right.

If you can imagine that silver pipe running to the edge of the engine and turning 90 degrees towards the rear there is a short rubber section that connects it to a fitting on the exhaust manifold.

Kevin

[RossMk2]

Thanks Kevin, thats defo been removed! Will check the manifolds to see if i can spot a joint.

[RossMk2]

UPDATE:

I told a little white lie I do have a fault code but i didnt believe it so didnt mention and have checked again and its there:

19!!!!!

That would mean its eaten another gm vauxhall crank sensor in about 6-9months, cant be right surely, and can this cause the problems im having?

[Jimbob]

Is that from the paperclip method, or have you got a reader / resetter yet?