Practical Standalone Tuning: Step 6: Idle Tuning

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Step 6: Idle Tuning

07.00

00:00	The next step of our process is to do a little bit of work around the idle setup before we actually go anywhere near the dyno.
00:06	What we're doing here is looking for a bit of a sanity check, making sure that our engine is idling happily, there's no mechanical issues in there, everything's working before we go and waste some time and money putting the car on a dyno only to find there's issues that we actually need to resolve first.
00:21	So, very first part of this is just looking at some of the key parameters for our engine's mechanical health and the starting point here is our oil pressure.
00:31	So, 29 psi, obviously the engine's still continued to heat up and idle from our last module, so it's up to operating temperature now, we can see our coolant temperature sitting at 192° but 29 psi at idle, quite happy with that.
00:47	Even if you don't have an actual oil pressure sensor like we do here, you'd at least want to monitor the oil pressure switch on the dash, make sure that oil pressure light is physically going out.
00:58	Another aspect here, this really comes back to our previous module as well, during the initial startup we obviously want to apply a little common sense.
01:05	If we're hearing some nasty mechanical noises, obviously we want to stop and resolve that, find out what the cause of that is.
01:11	And if we are also dealing with an unknown car or unknown engine, during the initial startup phase we also want to be pretty mindful that we aren't ending up with fluids leaking out onto the floor, so a pretty careful watch out over the engine bay while the engine is started for the first time is of course common sense.
01:29	Now, the other aspect here is we can see that our fuel pressure is now sitting at 60 psi.
01:33	You'll recall I said that when we're checking and setting our base fuel pressure, when we're just keying on, because we only have maybe 11.5 to 12 volts, it's not going to be a true representation of what we've got with the engine running, that's proven to be exactly the point here.
01:48	We also want to make sure that our alternator is charging and the number of times I've seen problems with this is actually ridiculous.
01:56	So, here we've got our battery voltage sitting at 14.1 volts.
02:00	It's very common to find that when we start the car that maybe, particularly in a car that's been rewired from scratch, that the alternator is not charging.
02:08	And we might not initially see this, if there's enough voltage in the battery, we'll get the engine to physically start and run and if we don't notice that our battery voltage is sitting at maybe 11.5 or 12 volts, we'll find that we will of course start to have the battery voltage drop away and eventually we won't be able to run the engine, it's going to waste a lot of time and any tuning we do under those conditions is going to have to be redone.
02:31	So, definitely want to make sure that our battery voltage is OK.
02:35	Also we want to make sure that our manifold pressure makes sense and this sort of comes into account of the engine RPM as well.
02:45	What I mean here is we want to make sure that we can make the engine idle at a sensible RPM for its configuration and specifically the type of cam that's fitted to it and both of those are going to also influence the manifold pressure.
02:58	Here we've got a stock cam, so we know that an LS1 here should idle at maybe 550 to 650 RPM pretty happily and I'd expect around about 30, 35 kPa, so we're pretty much exactly on the money there.
03:11	If we can't make the engine idle low enough, or where it typically should, where we could expect it to idle, if we find that as we drop the idle speed down to where we know that the engine should be able to idle happily and it keeps stalling, or we've got no manifold pressure, this could be an indication that maybe there's a cam timing issue.
03:29	And again we always want to get all of these mechanical issues sorted out before we go anywhere near the dyno.
03:35	OK, so everything's looking pretty good from that standpoint, what we'll just do as well is come through to our fuel tuning here and just show that now the engine's up to operating temperature, our closed loop's sitting pretty much right on zero and we've got our target and our measured air fuel ratio matching really nicely at 13.8.
03:53	So, this makes everything look like the VE table is tuned perfectly, it's actually not, we do have some learning going on in the background, but we will deal with the fuel learning system and how that works in the next module, so I won't dwell on that any further.
04:10	So, we'll come back to our idle tuning data monitor and I'll just point out here as well that if we click the little button in the top left here, we can actually modify what is being displayed on any of these data monitors and we may find that for example we don't want our GDI one because clearly this engine is not GDI and maybe we want to pull, maybe closed loop compensation down into our diagnostics panel here, so we can just drag and drop these as we see fit.
04:39	So, pretty easy to modify these to suit our requirements and it'll prompt if you want to save those changes.
04:45	So, let's just make sure we can also make changes to our idle speed.
04:50	So, we'll come up to our idle ICF here, click on that and we've got our settings here.
04:56	I'm not going to dwell on this because we aren't going to cover in detail the idle speed control calibration setup, but we will have webinars on this as well.
05:04	So, our idle sparks, we have got that enabled.
05:07	So, it is using idle ignition control here to help stabilise our idle speed.
05:12	And we've got our idle control is being controlled here by drive by wire.
05:16	Won't dwell on the other settings, we've got our IAC park settings.
05:20	So, these are the initial idle air control opening or drive by wire opening.
05:25	And these are used initially on startup and these will be way too high which is why the engine idled, so high initially during our first startup.
05:34	The IAC startup position is held for at 2 seconds in this case.
05:40	I think the default is actually 4, but I've dropped that down and then it will decay back to normal idle speed control over 2 seconds.
05:47	So, that's what will cause that flare.
05:50	Anyway we'll come to our idle speed control.
05:53	We want to make sure these are sensible numbers and it all looks pretty good here.
05:57	Let's just see if we can effect a change, so we'll just change our target to 600 RPM.
06:01	Straight away I can hear the idle note change and we can see our idle speed is not quite at 600 yet, but it's definitely dropped from our Let's just try taking this up to 750.
06:14	And again our idle speed comes back up, takes a little bit of time, but it is moving up towards 750.
06:20	So, we know that our idle speed control system is physically functioning, our engine's mechanically healthy, it's doing everything that I'd expect and our alternator is charging, we've got good oil pressure and we've got good fuel pressure.
06:32	This would also be the point where we can now go ahead and fine tune our ignition timing or static timing.
06:40	Of course, as we already have discussed a couple of times now, we can't actually adjust our timing offset, but even with this fixed configuration, as a sanity check, I would always still use a timing light to physically make sure that our timing is where we expect it to be.
06:54	Now, we can move onto the next step of our process.