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Discussion Starter #1
Has anyone noticed smoother, but slower acceleration after the 1st oil change. I believe regular 5W 30 oil was used (not synthetic) at 1,600 Miles.
I had the oil changed today from a main Subaru Dealer, and noticed the loss of punch (power) almost immediately. Its still quick, but not as quick as was before the oil change......
Any ideas why this might be? Any thoughts would be appreciated.
 

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They might have disconnected teh battery thus resetting the ECU which could cause some short term loss of performance.
 

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Discussion Starter #3
I called up the dealership. Apparently, they didn't disconnect the battery. However, if this was the case, what do u mean by short term loss of performance..once an ECU gets reset, how do you get the power back?
 

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Never heard of a disconnect to do an oil change before...hmm.

There shouldn't be any difference in performance, unless they went and threw some heavy height oil in there.
 

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Discussion Starter #5
I spoke with an STI tuning shop and they said the dealer should have used Motul 5W 30 oil on the first change (as per instructions from Subaru Japan - which apparently went out to all dealers).
However, I discovered that the dealer did not use Motul, but some regular Subaru branded 5W 30 oil.......(at least thats what they said)..So I am going to have it changed to the Motul brand next week.
===Questions===:
Is there any danger to driving with this "crap oil" in the meantime? Once I switch back to the correct oil, how long does this normally take to circulate (kick in)?
 

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That should not matter either. Motul is just expensive synthetic oil. I would be surprised if any Subaru dealer even has Motul oil. In fact if you get it through them you will probably pay a lot more then what it goes for normally. I had regular Subaru oil changes up to 6k miles and just switched over to Amsoil synthetic oil and filter. Haven't really noticed a difference yet. It seems to run smoother and maybe a tad better gas mileage.
 
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Mine has run way better since the first oil change. I attributed it more to being through the break-in finally though.

The car feels like it is getting progressively stronger as the mileage increases.

I changed my own oil, and used 5w-30 but not 'Motul'. I am not switching to synthetic until at least 10k miles.

mist
 

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Discussion Starter #8
I am going to switch to Motul 5W 30 oil and get the car dyno'd to see how much power I really have lost....that will tell me for sure....
 

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abatra1 said:
I am going to switch to Motul 5W 30 oil and get the car dyno'd to see how much power I really have lost....that will tell me for sure....
That won't help you unless you had it dynoed before the oil change, too. What are you going to compare it to?
 

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Don't waste your time or money. :roll:

No motor oil will make any power difference unless they threw gear oil in there....then you'd have a power loss.

Good lord......
 

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Discussion Starter #11
Hot Import Nights, Baltimore

I am going to compare the Dyno to the baseline STI results for HP/Torque/Boost. If there's a large difference, thats my proof when I take the results back to Subaru..After driving the car for a few days now, it feels like the Boost has been reduced (accross the entire range). Still not sure what they did to cause this problem, but I know a simple oil change wouldn't do it.
 

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It is possible that someone at the dealer took your car for a spin and hit the ECU's boost cut. This is also called "limp mode". You will not get back to normal boost pressures until you reset the ECU. Do you have a boost gauge to check peak boost?
 

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You will not get back to normal boost pressures until you reset the ECU.
If this is the case, then how does one reset the ECU. Also, how do you hit the ECU's boost cut? Wouldn't the rev limiter protect something like that from happening?

I ask because I noticed that my STI felt off its game after its oil change this week as well. I also noticed that there was 1.9 more miles on the odometer than when I dropped off the car at the dealer.
 

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You can reset the ECU by disconnecting the negative battery cable for 15-20 minutes and then reconnecting it. I'm not sure exactly how/how not to get to boost cut. I know that it happened to me when I tried WOT in 6th at about 95mph. This has nothing to do with the rev limiter......when it happened to me I was nowhere near redline. Do you have a boost gauge?
 

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No, no boost gauge on my car. I didn't like the one the SOA was offering thorugh dealers.

Sounds like I should get one though.

Thanks for your advise. I'll try the reset this afternoon.....
 

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I pulled the negative wire on the battery, waited for about 20 minutes and then reattached the battery. I then started the car and let it run for about 3-4 minutes while I reset my radio stations.

I then went for a drive and once the car warmed up I got on it a few times to see if I noticed anything. It still feels slower, like the entire spike in power between 3500-5500 isn't as strong as it used to be?

Does the ECU take time to remap or something? This is frustrating because you know the dealer is going to say nothing is wrong.
 

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It may take a little time to get back to optimum.....but a few WOT runs should be all you need. If you still think its slow after that, you'll have to take it back......if you know of someone else with an STi, you can compare it to theirs.
 

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Thanks much for the help!

I'll update the this thread if anything good/bad develops.
 

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Have you been able to remedy the situation Dutchman. I am having a similar problem after my 2nd oil change and resetting the ecu also did not work for me. If my car is running in "limp mode" how can I be sure the ecu has been reset? AFAIK on the older wrx's the tripometer would reset which is not the case on my STi unless Im doing something horribly wrong. Also I do have a factory installed boost controller and its reading .5-.7 bar MAX. I removed my JoeP mbc and attempted to reset the ecu again with the same results.
 
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