Acceleration power loss - HELP!

[Banshee]

You could check the O2 sensor outputs with a cheap* eBay ELM327 OBD2 adaptor, and a free version of Torque on a mobile.

(I did that when I started getting cat efficiency errors to see if it was a sensor or the cat.)




* By 'cheap', I mean as little as $6.50.

[Joshua Walker]

Hey guys, thanks for all the suggestions... appreciated and noted.

Quick update, I'm thinking it's definitely O2 sensor related, unplugged three of them over the weekend (had trouble finding the end of the fourth) and reset the ECU for good measure. They're still unplugged and so far, so good. Before that I'd without fail have trouble on a daily basis. Noticed too that my estimated distance on a full tank of fuel is displaying well over 500km again, I couldn't reach 500 with the issue present, not sure if that's related or just a major coincidence.

st_za, no sensors replaced as yet. Originally the code I was getting was for just one sensor (now I wish I could remember which), but at that point I was assured by the mechanics that it wasn't related and so continued to look for other causes. By the time the sensors were investigated, I was told there was no signal coming from all four. I was also getting a code for multiple misfires, so they replaced my spark plugs.

I guess the next thing to do would be plug the sensors back in, and see if by some miracle the reset of the ECU has made a difference. If not, at least I've narrowed things down a little.

I also have a crank angle sensor from spoondog to swap out as my next test if it turns out I've just been lucky the last few days.

[Banshee]

Seriously, order an OBD2 module from eBay, and install Torque or the like on your phone. The plug for it is the thing your right foot gets caught on near the accelerator.

Check the codes yourself & see what you have. There may be someone here nearby who has one that can help with it.

[Joshua Walker]

When you said cheap, I was thinking $100, not $5 haha... it's a no brainer! Do you need one with wi-fi to use with the mobile app?

[Banshee]

I got one with bluetooth for this, <$10 from memory.

The Bluedriver with all the extra troubleshooting info was ~$100US. But the cheap one to look at graphs of the O2 sensor outputs. They typically start off flat, then start cycling, & both upstream & downstream should cycle more or less in synch. When they don't is when the code gets set.

When you find one that isn't cycling, you swap the left & right downstream sensors over & try again. If the fault crosses over, it's a bad sensor. If it doesn't, it's probably a bad cat.

[Joshua Walker]

Brilliant, cheers for that, I'll get on it!

[Joshua Walker]

Just an update on this for anyone still interested.

Had the two upstream O2 sensors replaced, and plugged the downstream sensors back in. The power loss problem is back again, and now I'm getting a code for high O2 sensor voltage. Pulled the downstream sensors out again just to be sure and still the problem remains.

So it seems, upstream O2 sensors connected = power loss. Disconnected = no problems.

Mechanics are still recommending I replace the PCM, I'm at a bit of a loss now as to what else to try first.