560 fueling issue

[outinthewood]

I would suggest someone missed a meeting whilst thrashing out what was required between bearing supplier (SKF I'm told ?) and Husqvarna on the early ones ? and perhaps someone in design had a little rethink on the mapping later on ? 

I don't know about them using "much" less fuel,  less yes but of course going over the top on oil i.e. 40-1 etc can  also cause heat retention ?

Without doubt the cooling slot added in 16 is a huge improvement along with fully syth oil, add in the gutted muffler , however, on the 560 adding the 562 type air filter seems to sometimes leave the saw "looking" for fuel.  On long duration cuts it would seem to be looking for a little more on the over run and this leads me on to my guess that the 562 has a revised map on the chip as I don't get that "feeling" . I don't mean it's running lean but I suspect not far off !

Edited February 17, 2018 by outinthewood

[spudulike]

I think a lot of modern saws are on the edge of being lean purely to meet the environmental specs. I find a lot of 361, 461 etc running well over max revs with the limiters in place so am having to remove them, undoing the H screw by 1/3rd turn and refitting them just to get the saw back in to safe levels. I am sure the autotune saws are running close to the edge for the same reasons.

[Eddy_t]

Adding a high-top filter and a muffler mod draws more fuel through the system, and the saw compensates by decreasing fuel supply, after I modded mine, I had it plugged in to get the data on the carburettor (46/85). Most errors occur from people not understanding how auto tune's two position system operates, it's idle or WOT only, everything else confuses it.

[Stubby]

15 minutes ago, Eddy_t said:

Adding a high-top filter and a muffler mod draws more fuel through the system, and the saw compensates by decreasing fuel supply, after I modded mine, I had it plugged in to get the data on the carburettor (46/85). Most errors occur from people not understanding how auto tune's two position system operates, it's idle or WOT only, everything else confuses it.

Exactly .

[outinthewood]

This is what I was saying, release throttle and it is a little confused . During WOT is ok and the "looking for fuel" only happens for a very short time. I have the diagnostics on my laptop and it's interesting to see what error codes pop up ! One of the companys I cut for are also a Husqvarna dealer so had a chance to get to know the system . Not the same on the 562 so the AT must in sync with the larger ( increased airflow ) airfilter.My two ported 562's have no issues. Not a problem on the 576, change to larger airfilter and US spec muffler and AT just takes it in it's stride and by all accounts the 572 will be a lot "smarter" I mentioned the "looking for fuel" as it's interesting to see what peoples accounts of these saws are, a few years in and a few changes to carb and software and we are still learning .....

[Eddy_t]

This is what I was saying, release throttle and it is a little confused . During WOT is ok and the "looking for fuel" only happens for a very short time. I have the diagnostics on my laptop and it's interesting to see what error codes pop up ! One of the companys I cut for are also a Husqvarna dealer so had a chance to get to know the system . Not the same on the 562 so the AT must in sync with the larger ( increased airflow ) airfilter.My two ported 562's have no issues. Not a problem on the 576, change to larger airfilter and US spec muffler and AT just takes it in it's stride and by all accounts the 572 will be a lot "smarter" I mentioned the "looking for fuel" as it's interesting to see what peoples accounts of these saws are, a few years in and a few changes to carb and software and we are still learning .....

Regarding 'syncing' with increased airflow, the system is very basic, on position 1 (idle) it checks engine speed, if above programmed idle, increase fuel mixture, if below, decrease fuel mixture, and the same applies for position 2 (WOT). Regarding the 572xp, judging by the IPL and workshop manuals, it's going to be exactly the same as the 540, 550 and 560/562 in terms of operating system, although judging by patent applications, the introduction of lambda sensors in chainsaws is imminent. Although that could be something to do with Stihl's direct injection systems for reasons...

My saw is a first gen 560, s/n 2012 4500688, it's never hunted for fuel on idle or WOT, apart from initial start, where it drops speed on WOT 5 times sequentially before hitting max rpm. When it was plugged in after modifications (porting, muffler mod, air filter and base gasket removal), it had no error codes and those were the carb running settings for the saw. The software on each saw is one of 3 options that corresponds to the specific ignition module.
If anything, adding a high-top filter should cause the saw to be rich, as the increased airflow would cause more fuel to be drawn via Venturi effect, hunting for fuel would suggest an air leak, assuming by that term you mean a gradual return to idle rather than immediately? If you meant a bog upon return to idle before picking back up, that could indicate that the throttle position sensor magnet isn't lining up quite right (the Americans noted that issue fairly early on).

[outinthewood]

Now a few points to clearup, I would agree with you that the larger airfilter should cause the 560 to run rich as it would by doing the same on a non AT without any adjustment to the H needle saw but the AT seems to just cope fine . My comment about it seeming to be looking for fuel only happens after a long hard cut and if it happens it's for a split second as the cut is finished and throttle released and as I said "it seems to be looking" It has just been a odd little thing for the last 3 yrs !

When I said syncing  I would have been better to use the word mapping as I wonder if the 562 is slightly changed in it's set up , a trip to the ipl in order ! 

I  plugged my 560 after changing air filter and doing muffler mod and as you found nothing to report but having down the same with several others that had come in for repair I found it interesting on a couple of saws that had serious fault  codes were still running  so as has been noted in other threads the very simple AT can almost  mask a serious problem . I have seen a 576 that had never had the air filter cleaned and only stopped and died when part of the filter was sucked in and the same guy also killed a 550 in the same way, it died before the filter imploded. He said he didn't know you had to clean them !! Both in the same week. 

[Eddy_t]

Now a few points to clearup, I would agree with you that the larger airfilter should cause the 560 to run rich as it would by doing the same on a non AT without any adjustment to the H needle saw but the AT seems to just cope fine . My comment about it seeming to be looking for fuel only happens after a long hard cut and if it happens it's for a split second as the cut is finished and throttle released and as I said "it seems to be looking" It has just been a odd little thing for the last 3 yrs !
When I said syncing  I would have been better to use the word mapping as I wonder if the 562 is slightly changed in it's set up , a trip to the ipl in order ! 
I  plugged my 560 after changing air filter and doing muffler mod and as you found nothing to report but having down the same with several others that had come in for repair I found it interesting on a couple of saws that had serious fault  codes were still running  so as has been noted in other threads the very simple AT can almost  mask a serious problem . I have seen a 576 that had never had the air filter cleaned and only stopped and died when part of the filter was sucked in and the same guy also killed a 550 in the same way, it died before the filter imploded. He said he didn't know you had to clean them !! Both in the same week. 

Hmm, I suppose as it's dropping back to idle, the idle adjustment electronic gate switch has not been active in those minutes, vibrations would cause the valve to close, as it must be operated on an electromagnetic valve. I'm not 100% on that, as I don't particularly want to dismantle the mech just to see how it works, carbs being extortionately priced and requiring a computer to set up!

Do you know what the fault codes translate to?

[Stubby]

All I can tell you is my very early 560 ( 1 bolt less in the crank case halves ) has a muffler mod ( maybe some other internal stuff but I dont know coz the bloke who did it would not say ! )  a high top filter and cover from a 562  and an 8 pin power mate on an 18" .325 Sugi pro bar does not play up at all . It is a peach of a saw . Does not hunt , does not run on , just does the job .

Edited February 20, 2018 by Stubby

[peatff]

11 hours ago, outinthewood said:

I would agree with you that the larger airfilter should cause the 560 to run rich

If it's letting more air in it should do the opposite and weaken the mixture on any saw till the auto tune corrects the mixture.