With OAT around 3C or below. It usually crank for about 10 seconds and let got when I think Its on and then it usually dies down once. After that it is usually there within 5 seconds and off I go.
After about a minute of running if I shut her down and fire back up every start is instant without any issues.
But if you wish see for yourself: This video was this morning
I wrapped the nut on the oil cooler with an old T-Shirt. Obviously there is a leak there but it doesnât look quite as bad as I thought. Also it appears that it is only on one connection not both like I originally thought.
This is a good question. To me it did not make much sense that I was able to rise the RPM by reeving the engine at idle⊠Nor does it make sens that I was able to permanently lower RPM by essentially suffocating the engine with my hand. When I let go one would assume it would go back to whatever the amount of air supplied. So there is something weird going on but that is for now turned off by just disabling that switch.
This is a good idea.
I have replaced:
Cables, Plugs, Rotor, Cap.
Only old thing in the system is the coil.
Now I understand any of these may make âintermittentâ problems but I would not know how to check.
Unfortunately the timing is out of questions as it is been stuck since before I pulled the engine and it has been attempted by a total of 4 people to get it to move and we have all decided that it is in whatever position it is in for probably forever. It must be close enough since the engine has shown that it can run silky smooth on occasion.
So how would you go about it? Also I guess at some point I have to ask to what extent is the idle a problem or just the way it is. I would argue that my 2.0 TDI did not run smoother at allâŠYMMV
Indeed, David - the function switch, out of âoffâ, always powers the âcompressor clutchâ, whether or not a compressor is even fittedâŠ
However, direct power to the air valve cannot be constant - it would defeat the idle setting. The valve seems to have have a temp switch - but logic also implies that the valve should only be open in idle? Ie, a microswitch at the throttle? All of which may give a clue to the odd behavior?
Of course, just turning the function switch âoffâ when the incident occur should drop the idle. And disabling the function by disconnecting the valve solves the âproblemâ; most of us manage without the devise - though I admit it is usefulâŠ
[quote=âXJFamilyJag, post:1588, topic:400182, full:trueâ]
With OAT around 3C or below. It usually crank for about 10 seconds and let got when I think Its on and then it usually dies down once. After that it is usually there within 5 seconds and off I go.
After about a minute of running if I shut her down and fire back up every start is instant without any issues.
[unquote]
Could not play the video. MaxâŠ
ââŠdies down onceâ when starting implies insufficient idle air/petrol (settings?) - as would â5 secondsâ on cold restart.
The CSI only sprays briefly (4,5 seconds at 0C) during âfirst crankâ - then it needs a couple of minutes(?) to reset before it can spray again.
With a cold engine, petrol tends to condense on cold surfaces - reducing âavailableâ petrol. Also, with the everything cold, the actual combustion process is inefficient - the petrol burns as droplets rather than vapor. Together with the cold enrichment (CTS) it makes the engine perfectly driveable and responsive at all tempsâŠ
So your cold start problems can be reasonably ascribed to the missing CSI - irritating, and unnecessaryâŠ
I imported my Series 3 V12 from Germany in 2017 and it had (and still has) the leaper on the bonnett.
Although i have always wondered how a TĂŒV-PrĂŒfer could ever allow such a pedestrian ripper on any carâŠ
maybe because the pedestrian will already be dead when he getâs hit by 2 tons of British steelâŠ
Itâs illegal but these guys are people too and sometimes nice.
And Iâm sure many just overlook it because they think these were a factory item and donât want to open a can of worms. It would take a real asshole to require removal and a full bonnet repair.
The TĂV-aaSoP was doing them a favour.
as we currently have a lot of fog it offers a wonderful opportunity to take the car out to a really dark place, open the bonnet and let it run. If anything is wrong with the new wiring youâll see a (harmless though) fireworks of sparks jumping where there shouldnât be any.
Other than that Iâd give it a try and retrofit the parts you changed (if you still have them, of course) bit by bit. Iâm not enthousiastic about new electrical parts. Most orginal parts will do better after 40 years than new ones after 6 months. In particular, new rotors - even Bosch and similarly branded - sometimes seem to be freshly boxed scrap. You may wish to try to get your hands on NOS parts sometimes popping up on ebay.
Yes, I bought new ignition parts from one of the big suppliers and they failed after about 200 miles leaving me broken down at the side of a busy dual carriageway with 38 tonne lorries thundering past.
Itâs the Distributor Doctor for me from now on - when I fitted his stuff it was like someone had given me a new engine!
If you remember about a year ago when we could not get the car to run properly it ended up being that BOTH Distributor caps were shot. I got new cap and rotor from Lucas from the UK. The Coil of my car was leaking fluid and was therefore changed to the really rusty one of the parts car. I always tried both original parts before I went for new parts. I had to learn this the hard way when I bought new Champion plugs at SNG and 2 out of 6 where duds. The old rusted bosh ones I had were working better than that. I currently run NGKs
Anyway I just would not know how to check the ignition for anything since it only does it when hot and idle and not even all the time. How do you suggest I check anything? swap parts around? one plug at the time? and one cable at the time? That will take ages. Even so the car drives great. I just want to get it perfect because I know the engine can run smooth⊠It just doesnât want to do it all the time.
Can I rule out the coil? I mean either it fires or it doesnât right?
I think Aristides idea of the ignition being the problem is a good one because as the temperature rises the mixture gets leaner and thus making the ignition more important to work correctly. What is weird is that cranking up the idle mixture does not seem to help nor does it make any sens for the issue to be randomâŠ
I have now clocked 1600km since getting it back on the road. I like driving it and so far it performs pretty well. You guys were right about the fuel consumption. The sweet spot is somewhere around 100km/h. I tried this on a recent trip of about 250km and I got just shy of 12l/100km. Of course these number are to be taken with a grain of salt as the filler is huge and you can easily squeeze in a few liters more. I have been tracking it with an app. Highest was 36l/100 and lowest es 11,4/100 averaging at about 16,5l/100. In the city it is terrible. somewhere around 26-29. I think I can squeeze out a little bit more once I change the thermostat to 88c.
Still have at least one little oil leak. Coolant leaks are under control now. Level stays put. Transmission is also dry now. All in all I am slowly getting there.
Just one thing. I have no idea how all of the time I spend fiddling with the car would be possible if one were to just drop of a car like this at the mechanic. I just canât imagine that even an experienced mechanic would get this all sorted in a single visit. My guess at least in this country they would also charge more than the car is worth⊠Maybe this explains that I have never seen an SI in person at all. I have only seen a few S2/S3s in the past years.
Itâs not that easy indeed.
I imagine you checked and serviced the distributor mechanical/vacuum advance and all?
Play in the shaft?
Next would be ignition cables, they do make a difference.
Did you gap the spark plugs?
Does the six have an Ignition Amp? it might be tired.
You mentioned that you canât adjust the ignition advance? How so?
It would be good to see if going up or down has any effect on the lumpy idle.
[quote=âXJFamilyJag, post:1597, topic:400182, full:trueâ]
Anyway I just would not know how to check the ignition for anything since it only does it when hot and idle and not even all the time. How do you suggest I check anything?
[unquote]
First step is check spark with a triple gapped spark plug, Max - to observe any difference in spark quality when the problem occur. While a weak âyellowâ spark may run the engine, it also may not. Particularly the ign amp, but also the coil are heat vulnerable - and the âfrozen peaâ bag suggested may provide further indication.
Swapping parts is of course an option - but only safe if the replacement part has been proven âgoodâ. Intermittent faults are always tricky - they must be caught âon the hopââŠ
Fiddling with the AFM mixture screw is not really relevant - and mixture should really be verified by a gas analyzer. Set the screw 2 - 3 turns outâŠ
We tried to find a light tester but could not find a single shop that still had one⊠I think we tried to see where the rotor pointed and verified that it was âabout rightâ given that the engine can run smooth I would assume that it is not that.
I mean sadly I didnât get to drive it (yet) but it made all the right noises and felt right. Highway consumption and 0-60 (100) times are spot on. Not a timing thing, and I donât think itâs anything ignition. Of course I can be wrong.
Funny. Yes we talked about it. For the record mine isnât running nearly as rough.
Also, I feel like there is an issue with what he says. He claims his engine is running to rich by looking at the plugs. Then he fixes the issue with the AFM bypass screw that was 16 turns out to 4 turns out. That would actually make it run even richer⊠by allowing less un-metered air to bypass.
He also forgot to mention that the actual idle speed is adjusted at the air distribution block which is a few inches ahead of the throttle body. Itâs an aluminum casting with some hoses going hither and thither. I am glad it worked for him and I am sure he knows this stuff.
As for my problem the car makes no distinction if I close the bypass completely or turn out out 2-3 turns like Frank said. I opted to do as Frank suggested simply because leaning it out a bit would save fuel although probably negligible. But it doesnât change my problem. Albeit my engine doesnât stall. In fact I got stuck in traffic the other day due to an accident for almost an hour and I would think that the mighty XK would have not loved this, but nothing. Just the usual bit of up and down.
Based on what I read on this forum this engine is just very hard to get perfect at idle and also to cold start immediately. Some do, most donât. I will do some parts swapping and doing elimination work but maybe I just have to live with it as isâŠ
