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Old 01-22-2013, 03:06 PM   #453
Element Tuning
Former Vendor
Member#: 54918
Join Date: Feb 2004
Chapter/Region: MAIC
Location: Gaithersburg, MD
673 WHP Element
Tuning Pro Comp Engine

Default Cold Start Hydra 2.7

Inability to cold start with the Hydra EMS has been brought up numerous times so I thought I would address this and offer some tips to anyone that might be having some issues.

Element Tuning demonstration for 20 degree cold start using 2.7 Hydra EMS. The cold start was performed on a 2005 Subaru Legacy GT running an Element Tuning Pro Comp Engine equipped with big valve heads (+1mm, multi-angle valve job, bowl blend, OEM cams, Forged pistons) and 816cc fuel injectors.

Outside air temp is 20 F and the engine block and engine bay are showing 3C (it's possible the sensor calibration is slightly off or more likely it's a function of the engine bay being heated in the sun under a black hood due to a green house type effect).

As you can see the engine fires right up with proper cranking voltage and proper tuning. Even my 10:1 compression race car fires up in 30 degree weather using only a mini Odyssey battery. In that case your tuning needs to be 100% as you won't have more than 1 or two tries to start due to how small the battery is.

The number one reason for cold start issues is a lack of cranking voltage. The Hydra has many more processors and more powerful processors than OEM and they require over 10 volts to boot while cranking the engine. If you are having issues starting, make note of the battery voltage in your real time display. No amount of tuning will start a car with inadequate cranking voltage. We recommend a high end battery and when I say high end battery, a battery with a lot of lead in it. This would be something like a Diehard Platinum or if you are trunk installing go up to a larger battery (we typically use Toyota Tundra batteries for trunk installs) as the more lead plates you have the higher the voltage (cold cranking amps do not tell the whole story).

If voltage is acceptable then you can move onto tuning the many "starting" maps the Hydra provides. In most cases if the engine does not crank over in 2-3 seconds you're simply not delivering enough fuel and an adjustment to the "start primer," "cranking enrichment," or "coolant temp trim" fuel maps are in order.

For more information of starting the car please visit and view our "technical" page for tuning tips.

Phil Grabow
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Last edited by Element Tuning; 01-22-2013 at 04:24 PM.
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