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After you have now taken the car for a drive lets do this:

What are the values of the long term fuel trims now at idle? (only after the battery has been charged and the vehicle taken for a spin)

Earlier you noted
No pictures of graphs yet, but I did view the SHRTFT1(%) and SHRTFT2(%) graphs. No. 1 showed a kind of sawtooth pattern, with frequent drops and rises. No. 2 showed very stable sawteeth, with long periods at the max. 25 volts.
........... and THAT (the sawtooth pattern) implies the O2s cannot possibly be producing 0V only since the STFT is a calculated result from the O2 voltage measurements

You really do need a sensible upstream O2 voltage graph (on both S1B1 and S1B2) ..............

Unfortunately I am not familiar with your scanner but can tell you that as a general EOBD guide and then its up to you to figure how to get it out of the device
 

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Discussion Starter #23
All I can get out of the four O2 readings is 0.0 v, so I was wondering if there was something else to do with the scanner/ECU relationship that was blanking that data out. You have confirmed that, I think. As to working out how to get the info. out of the scanner, this whole event is my first and only encounter with one, so I have far, far less knowledge of its workings than you do! I never learned this stuff; when I was studying cars, we were still using slide rules!
I may have to go and see my garage fella, and see what his expensive scanner tells us. And pay for the knowledge, of course, but if I have exhausted all I can get, that will be the next step.
I'll be going shopping this afternoon, so I can read the long term fuel trims now at idle when I get back. Battery is fully charged now.
 

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Lets see what you ltft values say .............

Without the O2 values/graphs I would be loathe to suggest a way forward other than to replace all the plugs because chances are you may be spending money on unnecessary stuff while guessing (even though it may be educated)

I also grew up with slide rules .............. still have one in a drawer somewhere to prove my age :eek: :p


Perhaps some other fellow here would like to take a stab at a suggestion for you............
 

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Discussion Starter #25
Well, the plugs I can do. How much work is required to get at the rear ones, though? I don't have full facilities for vehicle servicing, it's all on a gravel drive. And my Haynes doesn't cover the V6.

Any help from others willingly received!

Cheers.
 

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Discussion Starter #27
Oh joy... Sounds like a good job for the garage! Maybe I'll drop by sometime and see about having Sean connect his scanner up and see if he can get some of the detail I can't, and ask him about the plugs. Lotsa money for a small job, except for the location.
 

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Discussion Starter #28
More info:
There is an entry under Live Data for Oxygen Sensors, or similar. It leads to the four sensors. Each one, when selected, comes up with: "This function not supported".
After a good run, the long term fuel trims were running at -21.1 and -19.8 volts, +/- a little. O2s are still at 0.0 v.
 

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The good news I guess is that the ECU is at least consistent ..............

Guess you will have to determine yourself how to move forward ............. if you do get it sorted please report back
 

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Discussion Starter #30
Ok. Thanks for the help, I have learned a lot about my scanner, at least! I might get six plugs, install the front three, and see if that makes any difference. If not, install the other three, one way or another.

Cheers.
 

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If you go the one bank with new plugs route - the ltft is a slow responding parameter, so if the plugs are the culprit, then you will need to drive the thing a day or so in order to see a change on the ltft on the specific bank involved
 
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