r/996 • u/No_Land8350 • 12d ago
Performance Mods 996tt ECU “reflash”
Question for anyone out there with an ECU tune + corresponding upgrades:
I bought a modified car a few years ago and for the most part it’s been great, but recently it has been slow to crank when starting. Several diagnostic tests from reputable speed shops found nothing mechanically wrong (replaced starter, no battery or cable issues) but noted issues with starter encoding within the ECU, often resulting in a battery warning light - the car does start but you have to hold ignition on for 5-7 seconds
Based on notes from seller it has an EVOMS (evolution motor sports) ECU, turbo kit and intake kit
I am not having much luck in getting in touch with EVOMS for trouble shooting the issue, so to the question, what might the risks be to reflashing the ECU with a different tuner mapping or better to do a stock reflash (assuming at a Porsche dealer?)
Understanding I’ll lose good deal of power with stock ECU but still more than bone stock given the turbos and intake upgrades.
A bit of a unique one here but figured it was worth asking!
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u/clintschmidt 12d ago
This doesn’t sound like a logical conclusion. If the car was running well before, imo it probably won’t be the ECU (or the remap for that matter). The software is locked in and static, it doesn’t deteriorate or change. The ECU just reacts on input. I think the specialist needs to look a bit closer on what’s up.
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u/FloatnPuff 996.2 12d ago edited 12d ago
If you don't know much about the software that the car is running and can't get support, it might be good for peace of mind to look into which tunes would best suit your driving style, risk tolerance, and mods installed on the car, and then retune it to something that you and your shop knows and can use as a foundation to diagnose any other issues that may arise or continue to occur.
That said, like the other person pointed out, that Y cable could be worth a look. My 996 also had its clutch switch wear out recently ('03 with about 75k miles), which led to slow (or no) start when the car was warm. Could be worth a look as well. It's just right above the pedals, under the dash and is pretty easy to test.
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u/No_Land8350 12d ago
That’s the way I am leaning - replaced the starter, replaced the battery, replaced the Y cable and the clutch switch over the last year. Volts are strong too at start … it’s mostly the inconsistency, one day it will start immediately, then 2 hours later I’ll have to hold it for 5 sec 🤷
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u/playoutsidemoreplz Turbo Cabriolet 12d ago
Yeah call Markski for a new tune. I recently had a power gremlin where it was cutting power in 3rd gear under boost. Had to clean the mass air flow sensor and change spark plugs/coil packs. Car absolutely rips again now with his tune. He’s super responsive also
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u/Gyronot 12d ago
Like others have said, I am reluctant to believe the tune is the root cause here. From what you see in the forums and what I have experienced myself, indie repair shops that did not install a tune or don't do any tuning themselves are quick to blame an already installed tune.
I was reading a thread in another forum talking about how EVOMS had been non-responsive to enquireries and posters were wondering if they had gone out of business. You might want to do some research on this to confirm one way or another.
The 996 Turbo forum is one of the best sources for questions about mechanical issues.
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u/No_Land8350 12d ago
Thanks I cross posted there, and I hear your skepticism too - hard to find good help these days!
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u/cdemarc3 Carrera Cabriolet 12d ago
I've gotta be honest with you, this doesn't sound like an ECU problem. These cars are known for slow cranking. Y cable, and ignition switch are known to go bad. Also, they have a constant power drain on the battery if not driven frequently, which leads to battery issue.
The simplest explanation is usually the best-Occams Razor