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The only place for a coil spring is up Zebedee's arse.
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Joined: Dec 30 2015
Posts: 1434

Well it's not bad, but it's not perfect....
The general symptoms are:
Low MPG (2.8/-2.9 miles/litre on LPG)
Hesitation on Petrol at about 3500 rpm on hardish acceleration (seems OK on WOT). No hesitation on Gas (maybe because the LPG is richer?)

I'd had a code showing a sensor fault for the upstream o2 bank1, which I tried to change but I couldn't undo the bloody plug*. So, just in case it was throwing the code because the LPG was running too rich for the ECU to lean it back out I reset the adaptive values and took it for a drive on Petrol only to see what happenned.

Immediately after reseting the adaptive values, the idle went to hell. Nasty and lumpy. It took about 5 minutes to get back to normal. Then I took it for a short drive. It was weak, very weak but it kept running and slowly improved.
Codes: Adaptive values out of range, both banks. Knock sensor (1 time). Strangely, I didn't see any misfires recorded on the misfire screen.

I cleared the codes and did ~35 miles on petrol on back roads and tried to get into every part of the rev range in low, medium and high throttle openings. It started out pretty grim but did settle down to being properly driveable, with the exception of the 2/3 throttle hesitation at 3500-4000 revs. You have two choices at that point, back off and let the 'box change up so you can pull away again at just below kickdown or just floor it and it moves on again.

Finally I parked her up and checked the codes again. This time just the "adaptive values out of range, signal too high" for both banks.
So.. I don't think the 02 sensor is necessarily bad. I've been watching the live output and they both seem to switch between the same ranges (about 0.01 to 1.4). Bank one did take a while to read anything from cold(ish) after the first reset - I don't know if that is enough in itself to require a swap. I have the part if necessary, just need to get it up on a ramp and get medieval on it's ass!

Does anyone have any suggestions? I can get whatever info is required from the Nanocom, I just wish you could tell it to "dump everything" to the SD card from Motronic, but if it does that I haven't found the option. Personally, I'm leaning back towards MAF again.. but I don't know these engines - yet :accept:

*I really suck at this :( I couldn't fit my hands far enough up the gap to get a decent grip on it, and I wasn't strong enough to do it with fingertips.

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Joined: Dec 30 2015
Posts: 1434

a couple of other things!
I noticed that the Rough Road Signal is flipping from 0V to 12V for about half a second every two seconds ish. NO idea what that's all about! but I suspect it has a lot to do with the suspension deciding to hit offroad mode on the motorway @70mph every now and then. The dancing suspension is a bit further down the list right now but if the RRS inhibits the knock protection while I'm having mixture issues I'm a bit more concerned.

I've noticed what looks like a water leak/drip a few times when my wife pulls away from parking. Coolant levels seem OK so I've kinda ignored it. To get at the O2 sensor I parked with two wheels on an 18" high verge and saw that the leak is a pretty steady drip on to/past the passenger side catalyst (that was the high side). Is there is a windscreen washer line or something above that area? It's been dry today.

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Joined: Jan 05 2016
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Those plugs can be an arse to get undone... especially when covered in oil!

The rough road thing I think is normal.

The water drip may be condensate from the air conditioning - if its clear it probably is. The drains are either side of the gearbox. If you get underneath and look up with a torch, you'll see the black rubber things that have a cross cut into them high up.

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Joined: Jan 06 2016
Posts: 2312

Probably no help at all, but mine will quite happily drip condensate from every joint in the exhaust downstream of the cats without there being any audible blow. Spent a long time trying to achieve a gas and watertight seal, then got bored and went off to do something more interesting!<br>
Back in the day exhaust systems used to have holes (around 1mm) at low points in the system just to drain off trapped fluid- or maybe they didn't and my memory's been addled by encroaching old age :-)

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Joined: Dec 29 2015
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RRS is derived from the ABS ECU if I recall correctly, not the suspension.

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Joined: Dec 30 2015
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gordonjcp wrote:

RRS is derived from the ABS ECU if I recall correctly, not the suspension.
Yes, I'm sure you're right. My mixed up mind had overlooked the fact that I was looking in the Motronic inputs and not the EAS!

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Joined: Dec 30 2015
Posts: 1434

Sloth wrote:

Those plugs can be an arse to get undone... especially when covered in oil!

The rough road thing I think is normal.

The water drip may be condensate from the air conditioning - if its clear it probably is. The drains are either side of the gearbox. If you get underneath and look up with a torch, you'll see the black rubber things that have a cross cut into them high up.

Ahh thanks. Aircon condensate makes a lot of sense. I'll check for sure next time I'm underneath (which probably won't be too long!)

I'll have another go at the O2 plug, my mate Bob did the whole thing in 10 minutes and I can't for the life of me remember whether he used something cunning to undo the plug or just relied on the fact that he has hands like molegrips.

I'll keep driving the thing for now and try to work out why the adaptive values would be out of range with no other reported faults. Airleak?

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Joined: Dec 30 2015
Posts: 1063

Could be the LPG pulling the adaptive values out of range - I get the occasional error on mine still and I think it is probably just from points in the LPG map where it isn't quite right so if I try and push it for a bit of power and the LPG system is not quite fast enough then the petrol ECU compensates and it pulls the short term fuel trim out of range. I need to hook the Nanocom up in instrument mode and take her out for a run whilst recording live data, and the switch from petrol to LPG a few times in different conditions/speeds and see what the trims etc do.

The rough road signal is normal - it should flip/flop between 0V and 12V - if the ABS ECU detects rough road, then it does something with the signal (either holds it high or low, I can't remember) to tell the engine ECU that it's on rough terrain and it then takes that into account with the readings from the knock sensors (which detect vibrations) so it doesn't trigger misfire codes when you're just battering it off road :)

I've nearly got a window switchpack ready for you aswell if you still need one? I've been battling with trying to get window switchpacks and door latches worked on, around work, and trying to do other RR bits for people!!

Marty

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Joined: Dec 30 2015
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Marty, I've been running it on petrol to eliminate the LPG from the equation - for exactly the reasons you describe :)

As for the switchpack - yes please but you'll have to talk me through it or I'll break something else!
(wood one, with sunroof?)
Cheers,
Miles

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Joined: Dec 30 2015
Posts: 1063

Ahh... in that case... if it's just running on Petrol then the plot thickens...

Switchpack... I should have one done soon - I've got a load of things on this week, so need to find a spot of time to test one in the RR and get it boxed up! It comes as just the switch unit, so you get to keep the current wood trim that you have - the switch unit itself is held in by some torx head screws to the surround..

It's pretty easy to so, few screws, one connector :)

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Joined: Dec 30 2015
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Water drip is almost certainly from the Air Con, it'll drip down either side of the gearbox (roughly level with the gearchange cable). The plug from the O2 sensor is clipped to the side of the sump (or it is on a GEMS) but there is a locking tab on the plug that connects to it that you need to squeeze as you pull the plug off. If the O2 sensors are switching but the adaptive values are out of range, that would point towards the MAF sensor. The Motronic is very fussy about these and doesn't like aftermarket ones apparently (the GEMS isn't too keen on them either). See what the Nano is telling you with airflow.

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Joined: Dec 30 2015
Posts: 1434

MAF.. heh. Exactly what Simon LPG suggested to start with. Better not tell him!
I'll prod the nanocom and come back with some readings if you don't mind looking them over. There's a lot on that page I don't understand.

Marty - I've still got this ABS ECU that I forgot to bring down to summer camp. I'm not keen to have it destroyed (unless it turns out to be a bad one) but if it could be of value to science then I'm happy to lend it to you on a long term basis. Should I send it down?

edit: Sorry - yes please to the switch pack! I'd like to get something off the list :)

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Joined: Dec 30 2015
Posts: 1063

Sorry, been busy the last couple of days - had a friend staying who's over from NZ and haven't seen them since 2012...

I've now got another job this week in London so having to head off on Wednesday and not back until Friday night, so again the P38 bits get put on hold :( But have a fairly free Sunday to do some testing and Monday to post off.

If you are happy to send the ABS ECU with the old switchpack, then I can use to for testing/checking components as 'known' values - it's not likely to get blown up luckily!!

I would also go with MAF for issues on fuelling on Motronic on Petrol - had the issues with mine, and still did it with a cheap aftermarket MAF - though with a genuine Bosch one to replace the faulty one, she was happy again!

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Joined: Dec 30 2015
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OK Marty, like I said there's no pressure on the switch pack. I'm definitely not backing out of the purchase but I'm happy to slip down the queue if you're busy. I'm concentrating on the fuelling for now.

I'll send you the ABS ECU with the switchpack for you to prod :)

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Joined: Dec 30 2015
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Back from a week holiday and there was the new MAF sitting there looking all shiny and new....
After a quick check online I worked out that EVEN I can fit one.
I also cleared the codes (again) and reset the adaptive values (again).

Much improved. Everything settled down really quickly - in fact I didn't notice any poor running at all this time - and nor did the ECU. I've just come back from 18 miles of country roads with no faults in the Motronic! She also seems a little feistier with the correct fuelling and the flat spot at 3500rpm seems to have gone.
I'll give it a few more miles before I'm certain but this looks like a result :) Then I'll try it on LPG again and see if that needs twiddling to suit the new MAF.

Marty, I saw your email come in thank you - I'll reply soon now I'm back at a PC.
Morat