Car not starting after tune

Shi

New Member
May 16, 2019
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USA
Hello everyone, new to the forum. Hope I’m posting in the right spot.

Anyways. Long story short, I’ve tried twice to use a stock tune from a SCT BDX, and after both installs my car wouldn’t start. The first time, it tried to rev a few times and died. The second time a similar situation, but it also didn’t want to start. I was able to successfully reinstall the stock tune with no apparent issues thankfully. Anyone know what could cause this? 2017 EcoBoost premium if it matters. The tuner showed a trouble code but I can’t remember exactly what it was. Something about the computer. Thanks for any help, and thanks for reading.
 
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I Bleed Ford Blue

Active Member
Feb 13, 2017
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North Olmsted OH
When ever you load a tune, you are supposed to have everything turned off, radio, lights, HVAC, wipers, etc. Also do not play with your windows or power seat while your waiting either, and close your door. Any slight variation in voltage while your loading a tune can corrupt the tune and turn your car into a brick. And sometimes glitches just happen. Either way your lucky you were able to recover, hopefully you wont have any issues next time.

If you've ever loaded a BIOS on a computer motherboard, well loading a tune is basically the same thing. You can very easily brick a computer if your not careful. Only difference is on a pc most likely it's permanent because your are rewriting the basic operating instructions and if they get corrupted, well your screwed. On your pcm you are just rewriting the data table to optimize performance on your engine/trans. The basic operating instructions are untouched. If you can't recover your pcm/ecm after a bad tune load, most likely you have a hardware failure.
 

Shi

New Member
May 16, 2019
3
0
1
22
USA
When ever you load a tune, you are supposed to have everything turned off, radio, lights, HVAC, wipers, etc. Also do not play with your windows or power seat while your waiting either, and close your door. Any slight variation in voltage while your loading a tune can corrupt the tune and turn your car into a brick. And sometimes glitches just happen. Either way your lucky you were able to recover, hopefully you wont have any issues next time.

If you've ever loaded a BIOS on a computer motherboard, well loading a tune is basically the same thing. You can very easily brick a computer if your not careful. Only difference is on a pc most likely it's permanent because your are rewriting the basic operating instructions and if they get corrupted, well your screwed. On your pcm you are just rewriting the data table to optimize performance on your engine/trans. The basic operating instructions are untouched. If you can't recover your pcm/ecm after a bad tune load, most likely you have a hardware failure.
I didn’t touch a single thing while I was uploading the tune. Doors closed, everything off. If I’m risking some sort of permanent failure, I’m going to throw in the towel and try and return the tuner. Not worth bricking something. I also wasn’t thinking, I installed a CAI before using the preloaded tune. Could that affect it that much?

And I get the BIOS comparison. Used to work on computers. Good comparison.
 

I Bleed Ford Blue

Active Member
Feb 13, 2017
335
82
48
52
North Olmsted OH
A CAI will affect the tune. Basically, the pcm reads the info from the mass air sensor and adjusts fuel/air based on other sensor inputs and what the data table tells it to do. When you change the CAI and it flows more or less air than the data table can adjust for it throws everything out of whack. Most out of the box canned tunes are designed to work with a totally stock engine. If you want to run a CAI or larger throttle body or something else that throws off the stock data table then you need a custom tune that compensate for the mods you have or intend to use. Basically anything that changes the incoming airflow or the amount of fuel delivered will give you a problem without a custom tune. Exhaust side mods will not affect drive-ability, but may give a Check Engine Light.

When I put headers on mine I got a CEL because the after cat O2 sensors were now too far downstream and not getting hot enough to give an accurate reading. I had to get a custom tune written to adjust for that and now it's fine.

Usually when you install a CAI or something else that is out of range of the parameters in the data table, it just runs bad and throws codes because it thinks you have a sensor fault. It's not common to get a no start condition.

Since you have pc experience, the tune is stored in a EEPROM, so the risk of permanent damage is negligible, but as you know, :poo: happens, Murphy's law, whatever you want to call it. I've used an SCT device several times on several vehicles and the way they work is first they read and copy the stock tune and store it internally on the device, then it erases what is there in the EEPROM, and finally it writes the new tune into the EEPROM
 
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Shi

New Member
May 16, 2019
3
0
1
22
USA
A CAI will affect the tune. Basically, the pcm reads the info from the mass air sensor and adjusts fuel/air based on other sensor inputs and what the data table tells it to do. When you change the CAI and it flows more or less air than the data table can adjust for it throws everything out of whack. Most out of the box canned tunes are designed to work with a totally stock engine. If you want to run a CAI or larger throttle body or something else that throws off the stock data table then you need a custom tune that compensate for the mods you have or intend to use. Basically anything that changes the incoming airflow or the amount of fuel delivered will give you a problem without a custom tune. Exhaust side mods will not affect drive-ability, but may give a Check Engine Light.

When I put headers on mine I got a CEL because the after cat O2 sensors were now too far downstream and not getting hot enough to give an accurate reading. I had to get a custom tune written to adjust for that and now it's fine.

Usually when you install a CAI or something else that is out of range of the parameters in the data table, it just runs bad and throws codes because it thinks you have a sensor fault. It's not common to get a no start condition.

Since you have pc experience, the tune is stored in a EEPROM, so the risk of permanent damage is negligible, but as you know, :poo: happens, Murphy's law, whatever you want to call it. I've used an SCT device several times on several vehicles and the way they work is first they read and copy the stock tune and store it internally on the device, then it erases what is there in the EEPROM, and finally it writes the new tune into the EEPROM
Thanks for all the info. Was hoping to save a bit in a the tune. The tuner has options for specific CAIs in it, would it hurt to try and pick one of those and see if it works? Can’t imagine different CAIs are so different that it affects the tune that much. Then again, I also didn’t think a CAI would affect a stock tune either. Should I just try selecting a CAI that’s listed and see what happens?
 

I Bleed Ford Blue

Active Member
Feb 13, 2017
335
82
48
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North Olmsted OH
If you don't know who made the CAI then just pick one and hope for the best, if it doesn't seem right try another. Keep trying until you get one that works well enough. Most likely there is one there that is close enough to work for you, if not then you either need to get a custom one written or put the stock CAI back on.

In the end most aftermarket CAI's are just bling, they are mostly for looks. Unless you have a built engine, I.E. cams, bigger turbo, ported head, etc. just a CAI will do nothing. And if it is too big on an otherwise stock engine it will slow air velocity and actually hurt performance. The engineers at ford tuned everything to work together and if you change just one piece of that equation it can hurt rather than improve performance. That's why I used a ford racing power pack on mine, it came with a bigger CAI, larger throttle body, and a tune directly from ford to adjust for those specific mods and it runs flawlessly. Just the power pack, headers, x-pipe, and mufflers gained me approx 65 hp at the flywheel.
 

ecostang

New Member
May 16, 2019
1
0
1
63
orlando fl
Hey ya'll im new to the site and just wanted to throw out my car and mod's.. I have a 2015 ruby red PP ecoboost with a roush CAI,MAP billet intercooler , resonator delete, denso 1 step colder plugs and a cobb stage 1 93 oct tune with a auto trans ... runs really good and all the mods work good together.... getting ready to do the oil change... everyone enjoy your car's !!
 

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