Cough cough Pt2 - Sound like an air leak?
Discussion
Ho hum, having taped up one air leak in one of the hoover hoses, she's still not running right.
Idle is fine, but power gets very lumpy/erratic/jerky between about 1k and 3K revs on a neutral or trailing throttle. Warps time and space as normal above 4K.
Does it hot or cold.
So...
a) Does that sound like I've still got a leak?
b) Or does the mix take time to adjust back to normal after a leak gets fixed?
c) Possible lambda sensor issue?
...and critically...
Is it ok to drive out to the Pistonheads Bournemouth Pizza evening tonight???
Thanks in advance,
Dave
Idle is fine, but power gets very lumpy/erratic/jerky between about 1k and 3K revs on a neutral or trailing throttle. Warps time and space as normal above 4K.
Does it hot or cold.
So...
a) Does that sound like I've still got a leak?
b) Or does the mix take time to adjust back to normal after a leak gets fixed?
c) Possible lambda sensor issue?
...and critically...
Is it ok to drive out to the Pistonheads Bournemouth Pizza evening tonight???
Thanks in advance,
Dave
Thanks chaps.
Blu3R said:
As said, reset your adaptive a first but I think you've got another issue.
Cheers - where can I get the software/cable to do that (unless there's some easier way, like pulling a relay or something?)? I checked the FAQ but couldn't find anything.Blu3R said:
What, if any, mods have you done recently? Look in those areas first.
No mods, but recently serviced with all plugs changed. First encountered the problem at the end of a 2 hour A-road/M-way run and first thoughts were something heat-related but it's the same when cold.verba1 said:
i've read you can disconnect the battery for 12 hours or something to reset adaptive map
A trawl through old threads has turned up advice to pull the main fuse (I assume that's the one labelled "Front Main" - no.17 in my 3R Handbook); for anything from 20 seconds to "a few hours"! I'll go and try that for a couple of minutes and report back... ...unless anyone has a definitive solution to resetting the maps without the software?
Dave2P said:
Blu3R said:
What, if any, mods have you done recently? Look in those areas first.
No mods, but recently serviced with all plugs changed. First encountered the problem at the end of a 2 hour A-road/M-way run and first thoughts were something heat-related but it's the same when cold.As for resetting adaptive maps - you're on the right lines but for how long I'm afraid I don't know. Pull it and leave it over night?
Dave2P said:
Thanks for all the input gents; much appreciated.
Any help? There's even a couple of wronguns from R0162 again for nostalgia!sjc said:
Are you 100% sure the plugs are gapped bang on correct? I'm sure I've read of similar before.
I'm going to pull the main fuse for 24 hours (just to be sure!) and will check the plugs tonight; should be 25thou IIRC?http://www.pistonheads.com/gassing/topic.asp?t=112...
Ok, have checked the front 3 plugs (didn't have time to do the rear bank) and they're all gapped bang on 25thou - and are NGK B7EFS so all good there. They look completely normal AFAICT (light brown/grey deposits).
Located the "vacuum line that shall not be pushed too far" and that looks ok; the port also has the prescribed notch in it so probably cross that one off too.
Pulled the main fuse again and will leave overnight and take her for a run in the morning.
Does the ECU re-learn quite quickly, or will it need a long run with a bit of variety?
...sounds like an excuse for a nice drive out in tomorrow's sunshine...
So what next? Is the exhaust a suspect? The exhaust is original and now 10 years old, so cracks and holes are a distinct possibility - might a leaky exhaust cause lumpy running?
Located the "vacuum line that shall not be pushed too far" and that looks ok; the port also has the prescribed notch in it so probably cross that one off too.
Pulled the main fuse again and will leave overnight and take her for a run in the morning.
Does the ECU re-learn quite quickly, or will it need a long run with a bit of variety?
...sounds like an excuse for a nice drive out in tomorrow's sunshine...
So what next? Is the exhaust a suspect? The exhaust is original and now 10 years old, so cracks and holes are a distinct possibility - might a leaky exhaust cause lumpy running?
As I said above, if it "warps time and space as normal above 4k" as you say it's unlikely to be any of these.
Low revs, light/trailing throttle and no boost are the easiest conditions for everything to cope with, so you need to look at things that only really affect it under those circumstances.
The o2 sensors are only used up to about 2k or a little higher and only on no boost, and the adaptive maps can hugely affect idle and low revs / low throttle running.
Are the exhaust tips black and sooty?
The other thing it could be is the ECU......
Low revs, light/trailing throttle and no boost are the easiest conditions for everything to cope with, so you need to look at things that only really affect it under those circumstances.
The o2 sensors are only used up to about 2k or a little higher and only on no boost, and the adaptive maps can hugely affect idle and low revs / low throttle running.
Are the exhaust tips black and sooty?
The other thing it could be is the ECU......
Dave2P said:
Pulled the main fuse again and will leave overnight
Well, fingers crossed, this (resetting the adaptive maps) appears to have done the trick.Just been out for 50 miles of varied driving and I think we're back to normal. Did feel a tiny hesitation a couple of times at 3K but nothing remotely like the "lumpiness" of the last few days and, I suspect, just what it's always done.
Many thanks for all the input here; much appreciated, and I've learnt some more about our cars.
Going to go and read about our ECUs now, for any clues as to what might have upset it (maybe the maps evaporated in the heat!).
Cheers,
Dave
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