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Discussion Starter #1
Hi,

You might remember me from such posts as "My baby...dead at 1000 miles". Heh.

Anyway, my STi had a sticky fuel injector #4 that flooded the engine. It was repaired under warranty (hooray!) but now I seem to have another problem. My STi idles very rough. I can watch the stick shake a bit and sometimes I can feel a knock through the dead pedal on the floor. It also seems to not have smooth engine noise when revving the engine in neutral at almost any constant RPM (2k, 3k, etc).

I have sat in a friend's STi and it idles *far* smoother than mine. Should I have the dealer check the compression on all 4 cylinders (especially the one that had the sticky injector)? Could a lower compression in a cylinder cause this problem? What else could cause a rough idle? Any ideas? I have a feeling that the service dept. will say that there's nothing wrong with the car since the check engine light isn't on.

Thanks.
 

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It sucks that the light isn't coming on, as that means their computer won't point them right to the problem.

Could be a lot of different things and it's hard to speculate....
 

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MY '05 production starts when?

The fact that there is no CEL doesn't mean there's not a problem. I'm not saying that I know what the problem is, but I would bring it back to them and state that your friend's STi idles smoothly and yours does not. If they tell you nothing is wrong, write a quick letter to SOA and send it registered mail. If anything breaks down the road....you can always say, "I told you so".
 

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holy crap you had a flooded engine adn such under 1000 miles adn they didnt get you a new sti? Unfortunately it'll never probably seem the same as a normal STi, mechanics can fix the problems, but usually the damage is still there (unless they replace the engine). Take it back until they get it fixed for good. See if you can possibly get a new STi or something, a stick injector? how often does that happen? sheesh.

Robert~

Also did they remove the motor at anytime during repairs? maybe the mounts arent seat right or something? Man I wish I had some kinda "cure" for your problem, but I have no clue, especially with no CEL.
 

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my idle has been odd as of late also, it actually stalled once at a red light the other day....anything I should check on??
 

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if you havent tried a grounding kit, those always seemed to fix idle problems.

Robert~
 

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Apexi AVC-R EBC for sale...

Ive had a lumpy idle since day one! :-? Sometimes its worse than others but its always there, I always thought the grounding kit thing was a scam but Im ready to try, where do you get one?
 

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Re: 8" subs in rear deck... what do u think?

im going to start building them and might start selling them if this works out well... and instead of about 5 wires, probably 10-15+ (to cover all teh normal ground points from every grounding kit, plus to get all the stock grounding points as well). Probably only cost $30-40 to make and sell for $50-60. Then instead of 4-6 8ga wires or 5 4ga wires you'll get a good bit. Im mainly going to do this for myself, but if others are interested I'd love to help them out.

Robert~
 

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I just did my own Hyper ground mod yesterday. 5 wires, 4gauge. Very easy. Do a search on Scoobymods.com or one of the other forums, you should find all the info you are looking for. Take a look at HUMMER's site, his car rocks, nice pics on nice add ons.
 

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Discussion Starter #12
I'm doing the mod tonight. I'll probably just do the simple three or four wire mod. I'll post and let people know if it really does smooth out my idle.
 

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Discussion Starter #13
oh

I installed the basic three wire grounding mod:
1) Negative battery terminal to driver side strut tower.
2) Negative batter terminal to the driver side of that fancy red manifold.
3) Passenger side of the manifold to passenger side strut tower.

I used 8-guage wire from Radio Shack with their 8-guage gold connectors that are meant for car audio use.

I fired up my STi, made a grocery run to get some dinner goodies, and let it idle when I got back. It was still rough, but was *far* smoother than it used to be, even after idling for almost two minutes. Woohoo! Who would have thought it would actually make a differenct :eek: ?? The idle was much more comparable with the other two STi's I've compared to in recent days.

I'm happy :) For less money than a tank of gas my car idles noticably smoother and the idle RPM has less variance. I thought this little mod wouldn't do much, but it certainly helped.

Cheap mod! Do it!
5 feet of insulated 8-guage copper wire - $5
3 sets of gold connectors for 8-guage wire - $12 total
1/2 hour of work if you have the wrong tools :lol:
Smoother idle - priceless :D
 

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Heater Effectiveness

I would also take your car back and tell them to fix it right or give you a new one. They probably would never do that but sometimes getting tough is what is needed. If the cylinder was flooded and washed down with gas the rings and piston could have been damaged since this would wash away the oil for a time. This could definitely cause a loss of compression and running problems. :roll:
My idle has been very rough hunting from the beginning. I am going to buy the grounding kit even thought I am somewhat skeptical. Hope it helps. I was going to complain to dealer but I figured I would be told that since the STI was a performance car that some of this would have to be put up with. What RPM should the idle be? When left to idle a few minutes it falls all the way down to about 400 RPM! Shouldn’t it be more like 8 or 900? Do you guys also have a very black sooty tail pipe and a engine throat cough between idle and 2500 RPM intermittently since day one? I am running 91 octane and have no ping. At least I don’t hear any (and I know what it sounds like). My car was built in late August 04 and just got off the boat about a month ago so I am wondering if it was already re flashed?
Thanks
Foghat STI
 

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1. Idle is supposed to be 500, I know pretty ow :-?

2. Everyoe thats dynoed with A/f has shown the car runs way rich in the mid range, hence the black tail pipe.

3. no "coughing" here, but mine was built in august/04 and no ping so I think your okay.
 

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OMFG IT WORKED!!!! :eek:

I cant belive it, I used to laugh at this mod, I replied to a post about this mod on the 350Z board that if they wanted the same results with less effort they should just put whatever it cost in their toilet and flush it. Well its been two days since Ive installed this and there is NO rough idle whatsoever. At used to get it when warm after running hard, like after getting off the freeway or at stop lights. Now nothing at all, it behaves just like my old Honda, amazing. :-?
 
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