6.1 Getting started 6 TUNING THE MS3PRO
the COP to the spark plug, and possibly ground the COP if it was bolted on. Connect your timing light over this
temporary plug lead.
If there are no timing marks on your engine, you will need to add some sort of marks. You can establish TDC
with a piston stop and add timing marks with either paint or timing tape.
Crank the engine and confirm that #1 timing is somewhere close to the Cranking Advance number set in
TunerStudio (this is set in section 5.3). If the timing doesn’t match and you’re in Fuel Only mode, you’ll need to
adjust whatever is controlling the timing. Otherwise, you’ll need to adjust the Tooth #1 Angle setting (if running
Toothed Wheel) or Trigger Angle / Offset (if running any other spark mode besides Fuel Only). If the timing is too
far advanced, increase this number. If the timing is retarded, decrease this number. If adjustments of more than 10
degrees are required, making the change, click Burn, turn the key off and restart the engine. Very large changes
don’t take effect until you turn the MS3Pro off and back on again.
6.1.4 Starting the engine
Now that you’ve confirmed sensor inputs, coil and injector outputs, have good rpm and cranking timing is close
you are ready to start the engine. Ensure the fuel pump is connected (since we disconnected it in previous tests),
battery is charged, and all hoses are secure. We recommend starting a data log as well. While the engine will
usually start if you’ve gone through all the previous steps for setting up MS3Pro, sometimes you’ll need a couple
more tweaks, and the data log can be very valuable if it comes to that. Go to the Data Logging menu, select Start
Logging, and enter a name for your data log. The log starts when you click Save, and stops when you either close
TunerStudio or go to the Data Logging menu and select Stop.
Now, hit the starter, and hope the moment for the big payoff has arrived.
It is common to need to give the engine a little throttle to keep it alive on the first start. If all sounds well, then
keep the engine running and warm it up. Check for oil pressure, coolant temperature etc. If anything sounds wrong
- stop and investigate.
Take your time! If things aren’t working out, then take a breather and come back another day. Come to the
www.msextra.com forum and ask for help. When posting, please include full details of your install: engine type,
make, model, ignition setup. The forum is global and we might not be familiar with your engine, so just quoting an
engine code is not sufficient. Don’t use the forum to vent your frustration, keep it calm...
If the engine kicks back, your timing is too advanced. Disconnect the injectors again and check with a timing
light. This can damage the starter motor if you ignore it.
If your engine does not spark, in spite of having a functioning fuel and ignition system and timing that appears
to be correct, here are several things we recommend checking that commonly will cause a no start condition.
• If you are running full sequential fuel and / or coil on plug ignition, try changing these settings to semi-
sequential fuel and wasted-COP ignition. This will rule out the possibility that the cam sensor hasn’t been set
up correctly, and you’re firing on the exhaust stroke instead of the intake stroke. These changes will make it
fire on both, which can be very useful for debugging startup problems.
• It may be refusing to start because the fuel isn’t quite right. If the engine does not go above cranking RPM,
try adjusting the cranking pulse width (the Cranking Pulse menu under Startup / Idle). If the engine catches
but dies immediately, try adjusting the afterstart enrichment (ASE Percentage under Startup / Idle). Both
of these are temperature dependent, so be sure you’re adjusting them at your actual coolant temperature.
There’s a couple rules of thumb you can use here.
– Start at what you think may be a lean value, then work your way up in small increments.
– Pull a spark plug after a failed start and check the electrode. If it’s wet with fuel, decrease the amount
of fueling. If it’s dry, increase it. And if the electrode is covered with crud, your problem may just be that
you need new spark plugs.
– If the engine responds better if you give it a bit of throttle, you probably have too much fuel (because the
extra air helps get your air/fuel ratio closer to what it should be). So you need less fueling. Conversely,
if giving it the throttle makes things worse, you probably need more fuel.
• Check for various physical problems. Some examples I’ve seen include coil packs or distributors with one or
two spark plug wires run to the wrong cylinders, a broken keyway on the crankshaft pulley causing the timing
marks to be 60 degrees off, and even a zip tie that got pinched in the intake manifold gasket next to a coolant
passage, which nearly hydrolocked the motor.
AMP EFI MS3Pro manual version 1.202, firmware 1.5.0, 4/21/2017 Page 105
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