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Discussion Starter #1
At idle or off the throttle what should our cars be sucking up? I just put on my boost gauge. I figure this is a good way to see if my compression is still good based on the vacuum psi.

And if you have a check engine light on then you go to advanced auto and turn it off with the odb scanner and DONT fix the problem as to why its throwing the code how many miles until the light will come back on? it should be a even interval like 50 or 100 every car is different.
 

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Mach1 FTW
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i found that my car runs best when the vaccum gauge reads right around -20in/hg.

both on my 2v and my 4v. anything less than that and it starts throwing a fit.
 

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Discussion Starter #3
Yea im getting 19.5ish i was just trying to see what the optimal should be. And i think its a good "compression" test per say?
 

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Mach1 FTW
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you got plenty on the vaccum side then.

i cant say much about the check engine light thing...i have noticed on my car once i clear it, it kinda comes back on whenever it feels like lol. until i actually track down the problem and fix it that is. sometimes it will stay off for a few days, other times just a few minutes. i suppose it depends how bad something is fubar'd
 

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US Air Force (retired)
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Mine runs right at 18 in.hg. at idle (20 off throttle). It always has. Hasn't change for years. If you have cams then it will be less. At high idle it will be less. I have a check engine (service engine soon) light that comes on once every six months for cat efficiency. I just have it turned off. I don't have stock cats. But, whether I take seriously the light depends entirely upon the code.
 

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US Air Force (retired)
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Jonny, do you enjoy worrying? Is there a reason you suspect something wrong?

I have 67,000 miles on my TR6s. They are running strong. They just dyno'd 396/370 a week ago (friendly dyno but nothing wrong).

What is the check engine light code you are so worried about?
 

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Discussion Starter #9
It says too lean on bank 2, drivers side. so i pulled the plugs and looked at them. Thats the best thing i know how to try to tell? I had my car tuned last october on a custom from scratch tune.

Now every couple hundred miles i get the SES light on
 

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Discussion Starter #10
Im not worried about the plugs going bad, just trying to find out if im ACTUALLY running lean. I got long tubes on and plugged the EGR on the drivers side.
 

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I think the plugs turn more of a white color when running lean. If I remember correctly.
 

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Mine is at ~ 17.5 at idle and will hit 19 off the throttle.
 

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Reading those plugs I can tell you're running a little lean. Is you're fuel pressure good? Are you running boost? How much? The timing seems to be OK on the first plug, but it's faded by the lean spike. Nothing drastic, just a bit lean. Have you heard any pinging under WOT? A/F/Wideband installed? What's the gap?
 

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My idle vac is -19 and -21 after WOT. -16 with the A/C on.
 

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Discussion Starter #17
Reading those plugs I can tell you're running a little lean. Is you're fuel pressure good? Are you running boost? How much? The timing seems to be OK on the first plug, but it's faded by the lean spike. Nothing drastic, just a bit lean. Have you heard any pinging under WOT? A/F/Wideband installed? What's the gap?
I dont have a fuel pressure gauge. Im running 10psi max at 6k but i havent gotten into it since the tune. I hear no pinging when wide open. No i dont have a AF installed. The gapps are .32
 

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.32 is fine for your boost level. Mine are set a .26 and they are BR7ef, much more boost though and my minimum level is 10 psi.

So what exactly is the problem? They do look a bit lean but nothing I'd be worried with your psi amount. If you got a "lean" code is coming from the 02 reading such condition but it won't be from bad spark plugs.
 

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US Air Force (retired)
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It says too lean on bank 2, drivers side. so i pulled the plugs and looked at them. Thats the best thing i know how to try to tell? I had my car tuned last october on a custom from scratch tune.

Now every couple hundred miles i get the SES light on
Ahh, yes. Now I understand. What is your A/F ratio? Your custom tune should have told you this.
 

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if you are running stock cams you should be at least around -20. I have stage 2 comp cams and at idle I get about -15, -20 if I give it any gas at all. And then It goes up to +8 for some reason under full throttle ???
 
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