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Discussion Starter #1
new to this, so please bear with me. :)

installed a Lunati Voodoo # 60511, IN/EX 222/228, Gross Valve Lift IN/EX .567"/.567", LSA / ICL 113/109, Valve Lash IN/EX Hyd/Hyd, RPM Range2000-7000.

it is supposed to have good street manners. with the stock tune, the TPS???sensor light comes on, shifting is now eratic, loss of vacuum on brakes and doesnt really do much until 3000+. i took it to a guy to tune it and it still runs like crap (dont trust his tuning capabilities though).

without a tune will it run that bad?
will a tune imrove the driveability drastically?
what is the TPS sensor?
any ideas what needs to be changed when being tuned?
can you elaborate a little more on the LSA and how it effects the lope and power curve.

Thanks guys.
 

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efilive evangalist
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167 Posts
You are likely running way more overlap than stock so idle needs more air. That might be triggering the tps (Throttle Position) error. As you say its all tuneable.

intake + exhaust duration / 2 - lsa * 2 = overlap. In your case -1 at 0.050 but you really need to see the total durations. Mine is -6 at 0.050 and +56 total.
Any real +ve overlap will affect lope, vacuum etc.

Anyway best to take it somewhere useful to get a proper tune done.
 

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The Psycho 10 sec. Goat
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1,968 Posts
I'd actually suspect that you missed something on your re-install of parts. The loss of brake vacuum is a big clue. I had no problems like that with my larger cam prior to tune. I also didn't have a TPS light come on.

TPS is your Throttle Position Sensor. You don't mention what year your car is and the Throttle Body is different from the 04 (cable) and 05-06 cars (fly-by-wire). On the 04 the TPS looks like this . . .

Just happened to have one sitting here at the desk. It is mounted right on the side of the Throttle Body.

At any rate, I would look for missing connections. Make sure the TPS is plugged in, check your vacuum lines. If you changed out springs, check the vacuum line going to your brake booster, because when you do that driver's side rear valve spring, you are smack up against the booster. Also check your connections on the front of the motor.

Your cam is actually a sedate, moderate cam which should have reasonable street manners without a tune. You should still see some decent power gains and with the 113 LSA you will have a noticeable, but not obnoxious lope when tuned. I'd recommend that you don't hammer on the motor until you get the problem fixed.

Finally, did you check the cam itself to make sure it was the correct part? We've all found products mis-packaged before. A friend of mine recently installed a cam and found one of the pushrods to be noticeably shorter than the others, though it was stamped the same 7.400" as the others. That is why I say to avoid hotroding the motor until you get things sorted out. A much bigger cam can result in valve float and piston to valve clearance issues.

If you get to the point that you suspect it is the wrong cam, short of pulling the cam to check it, I'd get the car to a skilled engine builder and they can check valve timing events just by pulling the valve cover.
 

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450 whp 432wtqw
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127 Posts
i have a problem like this in my 05.
it gets to high of a signal and sets a tps mismatch code goes to saftey mode
i must then turn the car off and key back on move the gas pedal a few times to relearn it start it up and its redeay to go again

b20
 
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