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Practical Diesel Tuning: 2. Prepare Vehicle For Tuning

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2. Prepare Vehicle For Tuning

03.21

00:00 - Once we've got the base files safely stored away, the next task it to prepare the vehicle for tuning.
00:05 The requirements here will depend to a degree on what vehicle we're tuning as well as what system we're using for the tuning.
00:12 But there are some general aspects that will be applicable to most jobs and we'll cover those here.
00:17 The first aspect to deal with in this step is to fit the required sensors to the vehicle to allow us to monitor our tuning progress.
00:22 As we've seen in the required sensors module, this at a minimum should include an EGT gauge.
00:28 It's also advisable to fit a wideband air/fuel ratio meter and boost gauge.
00:31 Where possible, these should be connected to the datalogging software so we can log these parameters along with other engine vitals.
00:38 If you're tuning on a dyno though, it's sufficient to run these additional sensors into the dyno.
00:43 The key is we want to know exactly where in the map something's occurring so we can deal with it correctly.
00:48 Once we have our sensors installed, we want to also inspect the vehicle and make sure there aren't currently any tuning modules wired in that would be affecting the factory tune.
00:57 This can be a common occurrence, particularly in older diesel vehicles that have been through multiple owners and have an unknown history.
01:04 It's worthwhile having a thorough inspection of the wiring harness around the stock ECU as well as in the engine bay to ensure nothing has been modified or added.
01:12 This of course doesn't rule out the possibility that the stock ECU has already been tuned previously but this should become apparent shortly.
01:19 Now that we know what we're dealing with and we have our sensors installed, we can lay down a base run on the dyno and see where our power and torque are.
01:25 We want to do this after we've fitted our sensors so that we can also assess the state of the existing tune and this will immediately give us some insight into how much potential we have to make more power and torque.
01:36 For example, if we find that our EGT is already getting up to 750°C plus or 1400°F, and we know we're already borderline and there may not be a lot of potential power available.
01:48 It would be unusual to find EGT reaching this sort of level on 100% stock vehicle though.
01:52 This would immediately make me suspicious that the tune had previously been modified.
01:57 This can be a little tricky to confirm depending on your particular vehicle, in a perfect world we want to compare the current tune to a trusted stock calibration and for vehicles you're tuning all the time, this should be pretty straightforward.
02:09 If this is your first tuning job though then you're obviously not going to have a library of stock files to compare against so it becomes a little bit of a job sourcing such a file.
02:16 A good way of doing this is to reach out in the help forum for the reflash provider you're using and ask for a stock file.
02:21 You may fine there's a tune repository available such as the one for HPTuners or you might be able to source the stock file easily.
02:29 If these options fail then it's also worth emailing the reflash provider directly and asking them if they can provide you with a stock file.
02:35 You may wonder why we can't just work from a modified calibration and the reality is that we can however it isn't recommended because then you're making the assumption that whoever did the job last did it correctly.
02:46 Sadly in the aftermarket tuning industry, this is not an assumption you want to make.
02:50 There are likely to be all sorts of errors and mistakes baked into the tune that may not be immediately apparent.
02:55 Of course in some situations you may have no choice but to work with what you have.
02:59 The point is that whenever possible it's good to start with the stock calibration and modify from there.