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glgraham_2000 02-27-2013 05:16 PM

Can tunes go bad?
I have had a 2005 Legacy GT since it was pretty much brand new. I have had my Cobb AP installed with a custom stage 2 tune from TDC since the begining. Going on 90k miles with the tune. I have 110k miles now and all the sudden, the car will not start sometimes. I would have to reset the ECU with the Cobb AP to get the car to start. Over time, that stopped working and I had to wait 15 to 30 minutes until it would start after reseting the ECU. I took it to the dealer and they said there must be something wrong with the tune. I have had the same tune for 90k. How all the sudden does it go bad?

I decided to uninstall the the Cobb AP to run the factory tune to see what happens. The problem went away. Drove around with the factory tune for a few days and it started everytime. Besides the CEL comming on due to my exhaust mods and removal of sensors, the car ran perfect.

I decided to reinstall the Cobb AP and my custom Stage 2 TDC tune. After the install, I have not had a single problem for the last week.

How does that happen? Does the computer start rejecting a tune after 90K?

Any ideas?

robitrice 02-27-2013 05:39 PM

my guess is that its unrelated to the tune, could be a simple ground wire that needs to be cleaned causing a bad connection. Tunes are not gonna wear out or go bad unless the ECU bricks. It sounds like some sort of electrical issue though in the ignition system. How is your battery?

glgraham_2000 03-01-2013 12:06 PM

What is nuts, is that the battery in less than a year old and working great. I uninstalled the Cobb AP and reinstalled it and all is back to normal. If it were a ground wire, I should still have the problem, right?

iNVAR 03-03-2013 08:12 AM

Just to confirm, tunes don't just suddenly go bad, nope.

glgraham_2000 03-05-2013 01:04 PM

In my line of business with servers/computers and software development, code just doesn't stop working with out something else not changing. Like a hardware problem causing the code to not function properly or not function as intended. Something usually changes or another variable in the equation changes. So I just need to find out what hardware is not functioning properly. The dealer is of course blaming it on the map/tune from the Cobb AP. I personally think it just needs a tune up. New plugs, etc. I'll get a tune-up and see if it runs better. Has not had one in 110k. :-)

GTTuner 03-05-2013 02:53 PM

The ECU has an adaptive strategy and will "change" a tune over time but it will not cause a no start. Re setting the volitale memory will put it back.

scoobyscoodle 03-05-2013 03:10 PM

Was this the off the shelf cobb stg2 map?

glgraham_2000 03-05-2013 04:44 PM

I believe it was the Stage 2 COBB off the shelf map. Then TDC took it and did a etune by looking at the logs and making adjustments a few times. It is the off the shelf map for Arizona. Why?

lee07 03-06-2013 10:15 AM

Need's a tune up. Plug's, fuel filter, injectors, something is going out that's all

Air, fuel or spark

glgraham_2000 03-06-2013 05:48 PM

K&N filter was cleaned already and it is still doing it. Did it again today. So must be fuel filter or spark plugs. Having that done next week. Will update results then. Thanks for the input.

Nrw 03-07-2013 06:51 AM

Wait, you're plugs haven't been changed at all? If so there's a problem.

Since you're a little after that time, you've atleast changed the timing belt right?

bucko3the7man 03-07-2013 06:52 AM

Holy hell, 110K on one set of plugs?

doccrowley 03-07-2013 06:56 AM

Time to service your car.

glgraham_2000 03-08-2013 08:34 AM

Yep, 110k on the original plugs. Not bad. :-) Dealers and mechanics kept telling me not to change them unless your having a problem. Have not had a single problem until the last month. Yes, I have done all the other routine maintenance, timing, and all other belts, among just about everything else it seems.

Another thing I am hearing and can't seem to find in the manual is when to change the gas filter. Again, I am hearing from mechanics and dealers, for our LGT don't mess with it unless your having a problem as it is part of the fuel pump, mounted in the gas tank and was design to be a lifetime filter. That still sounds odd to me.

Nrw 03-08-2013 08:43 AM

Sounds like lazy mechanics. Interval is every 60k IIRC.

AFAIK there's only one filter on our fuel system attached to the pump and there's no service interval for it.

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