Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: DTC79 on 06 November 2013, 07:52:12
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Hi all,
Have a 2001 2.6 V6 with only 68,000 on the clock which we have owned for a couple of years. About four months ago it started running rough (hunting) at times from cold and I was advised to change the air flow meter. An aftermarket replacement was sourced (I have since been warned these don't last long or even work at all sometimes)which seemed to solve the problem. A week ago started having problems with the rough running and even to the point of cutting out! I sourced a guaranteed second hand part from a vauxhall breakers and fitted it last night - the car runs even worse with the new one. I will obtain a replacement part from the breaker today and see if that helps. In terms of diagnosing that it is the air flow meter I pulled the lead off it and the car seems to run sweet as a nut without it connected. Problem is could this be something else? Would it be worth running the paperclip test?
Help appreciated
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Pedal trick on 2.6 :y
How does it run with MAF disconnected?
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Pedal trick on 2.6 :y
How does it run with MAF disconnected?
Sweet as a nut :y
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Faulty MAF. With lead to MAF diconnected engine runs in a default mode using information from throttle position sensor and other sources. You need a new MAF. Very dear from Vauxhall. MY trade club Vx dealer advised me to buy off the web! I did so. New MAF cured fault, car ran perfectly for 3 years until daughter wrecked it.
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I will try and get a replacement from the breaker today and try fitting along with the pedal trick tonight when I get home. Guess I could have been unlucky and got a duff replacement part. Would have bought a genuine new one, but the cheapest I could find on line was £170.00!! Just a question, do you have to reset / erase any fault codes after fitting the new MAF? I didn't have to do this the last time I changed it.
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If it is any help to you, I replaced my MAF 2 months ago on my 2.6 (2001). The fault codes present were P0170 & P0171, fuel trims. As it was common to both banks and no air leaks, it pointed to a failing MAF. I did run live data to check O2 sensors function, fuel trims etc which gave me enough confidence to condemn the MAF. MAF replaced and fuel trims back to normal, no more codes.
If you do diagnose the MAF, I had an original price from the dealer for £220 inc VAT which they immediately discounted to £180 on questioning. In this case Euro Car Parts had an OEM Bosch part same day available (do get them to confirm it is OEM though). They wanted £180 inc VAT but settled on £140 on negotiating. I'm sure there will be better deals out there but I felt happy enough sorting it same day rather than chasing around.
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If it is any help to you, I replaced my MAF 2 months ago on my 2.6 (2001). The fault codes present were P0170 & P0171, fuel trims. As it was common to both banks and no air leaks, it pointed to a failing MAF. I did run live data to check O2 sensors function, fuel trims etc which gave me enough confidence to condemn the MAF. MAF replaced and fuel trims back to normal, no more codes.
If you do diagnose the MAF, I had an original price from the dealer for £220 inc VAT which they immediately discounted to £180 on questioning. In this case Euro Car Parts had an OEM Bosch part same day available (do get them to confirm it is OEM though). They wanted £180 inc VAT but settled on £140 on negotiating. I'm sure there will be better deals out there but I felt happy enough sorting it same day rather than chasing around.
Sorry, typo, I meant P0173 not P0171.
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Thanks for the advice all, I will report back this evening on how I get on
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If you have access to Tech 2 get your 'learned values' reset.
When I repalced a faulty MAF on mine it would hardly run with the new one as the incorrect readings from theone being replaced had sent the trims way out. Old one back in, drive to nearest Tech 2, learned values reset, installed new MAF and all good :-)
I think this will only apply if your old unit went faulty in the sense of giving incorrect data rather than stopping completly.
Steve
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Thanks Steve,
I have the replacement part and will fit it when I get home. If I need Tech 2 is this a Network Q job or will a local garage be able to do this?
Cheers
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I think the general view is that on the 2.6/3.2, the MAF degrades gradually whereas on the 2.5/3.0 it typically completely fails. If it is the MAF at fault on yours, you should not need Tech 2 but you may wish to reset the codes/MIL after the repair. If the fault still exists, the MIL/codes will reappear at some point after resetting. I would recommend you read all codes before resetting and ask on here if you see anything unexpected.
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I bought 3 replacement MAF sensors for Nissan Sentra, they are Bosch type, possibly like Omega sensors, they looked exactly like sensor for my Catera.
1. Used from ebay $35
2. New from ebay $20
3. Remanufactured from auto parts store. $139
Only one of them was good, guess which one?
One of bad ones made engine run rich (0.9V O2 sensor), another one lean (about .1V)
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I bought 3 replacement MAF sensors for Nissan Sentra, they are Bosch type, possibly like Omega sensors, they looked exactly like sensor for my Catera.
1. Used from ebay $35
2. New from ebay $20
3. Remanufactured from auto parts store. $139
Only one of them was good, guess which one?
One of bad ones made engine run rich (0.9V O2 sensor), another one lean (about .1V)
I would guess the used from ebay. I find used parts are usually OK, having been removed from scrapped cars, and are unlikely to have been the reason for it being scrapped.
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Thanks to all for the advice, fitted replacement part last night and car runs great. Took it out for an hour after fitment and drove on various different roads and no cutting out or stalling! Also runs better as there was an increasing smell of petrol over the last few weeks or so from the exhaust so I guess the forty quid I paid for the replacement should pay for itself in petrol?!!
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Yep, 2.6s seem very sensitive to the MAF degrading for some reason and 2nd hand / pattern parts are a waste of time for this item.
Fuel trims do, I believe, reset if the ECU loses battery power, and they can cause rough running for a minute or two when the MAF is replaced, so it might be worth unplugging the ECU / Battery for a few minutes of this problem occurs.
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I'd avoid 2nd hand items for 2.6/3.2 MAFs, as they tend to misread with age, rather than actually fail.
To reset trims on a 2.6/3.2 with just a cheap OBDII scanner that can only read codes, cause a fault code (eg, unplug MAF with engine running, then plug it back in), then clear the codes with a cheap OBDII scanner. This resets the learned values.