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Old 11-18-2010, 09:13 AM   #1
AverageJoe
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Big cam in 350 tbi, high idle...

Okay i just got a lunati voodoo cam in my 350 5 speed and its tbi. My idle is really high and its only lopes when you are on the brake and rolling in 1st, once i throw it in neutral the revs increase ALOT. How can i get my idle to drop for the cam to take effect on idle in neutral? People dont believe i have a cam and its pissing me off somewhat. Something to do with a remapped computer? Bypass it? help please. I dont want to go carbed at this time

Last edited by AverageJoe; 11-18-2010 at 09:15 AM.
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Old 11-18-2010, 09:27 AM   #2
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Re: Big cam in 350 tbi, high idle...

Man your giving that computer a headache, the computer is compensating for the cam and trying to smooth it out because in a sense it thinks it has a miss. You will have to have the computer reworked to make it even run right. How big of a cam is it?
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Old 11-18-2010, 09:37 AM   #3
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Re: Big cam in 350 tbi, high idle...

x2 custom computer chip to even run right, maybe it'll lope then not sure. If not you gonna end up going carb probably if a tune won't do it.
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Old 11-18-2010, 09:43 AM   #4
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Re: Big cam in 350 tbi, high idle...

Tbichips.com
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Old 11-18-2010, 09:51 AM   #5
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Re: Big cam in 350 tbi, high idle...

The TBI trucks do not tolerate much of a cam change without a GOOD custom chip and some tuning.

If you attempt this you better have a scan tool that reads data and know how to use it, or be lucky so things work out.

You need to check the minimum air rate
Check for vacuum leaks
Check the IAC count with the engine warm and all accessories off

You need to know what the desired RPM the chip is programmed for.

Where did you get the custom chip from?
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Old 11-18-2010, 10:28 AM   #6
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Re: Big cam in 350 tbi, high idle...

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Originally Posted by ChevyTech View Post
The TBI trucks do not tolerate much of a cam change without a GOOD custom chip and some tuning.

If you attempt this you better have a scan tool that reads data and know how to use it, or be lucky so things work out.

You need to check the minimum air rate
Check for vacuum leaks
Check the IAC count with the engine warm and all accessories off

You need to know what the desired RPM the chip is programmed for.

Where did you get the custom chip from?
Its the factory chip, its a 91 model. It runs perfect besides a bad throttle response (rich it seems)

Last edited by AverageJoe; 11-18-2010 at 10:29 AM.
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Old 11-18-2010, 10:30 AM   #7
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Re: Big cam in 350 tbi, high idle...

i believe its .489 lift 268 duration

Last edited by AverageJoe; 11-18-2010 at 10:32 AM.
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Old 11-18-2010, 01:22 PM   #8
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Re: Big cam in 350 tbi, high idle...

Ouch. Yeah anything more than an RV cam will need work and more money.
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Old 11-18-2010, 04:26 PM   #9
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Re: Big cam in 350 tbi, high idle...

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Ouch. Yeah anything more than an RV cam will need work and more money.
Yeah i guess ill just have to wait and switch intakes and go carb'd
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Old 11-18-2010, 04:43 PM   #10
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Re: Big cam in 350 tbi, high idle...

why not mess with a chip? If everything works good
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Old 11-18-2010, 06:25 PM   #11
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Re: Big cam in 350 tbi, high idle...

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why not mess with a chip? If everything works good
id probably have more power with 4bbl carb, i know this tbi is killing my motor right now. its not stock,
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Old 11-18-2010, 08:37 PM   #12
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Re: Big cam in 350 tbi, high idle...

True but if it is tuned right you will like the injection way better than a carb.
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Old 11-18-2010, 08:45 PM   #13
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Re: Big cam in 350 tbi, high idle...

dude, that cam is tiny. you have some issues elsewhere. I am running a 383 with .510 lift in mine, well .522 with the 1.6 rockers. you need to check a few things. number one, with larger cam, more air is sucked into the cylinders by the longer valve cycle. as stated before, you need to check min idle setting, reset the IAC, be sure timing is set at 0 with timing port unplugged unless you are running advance in your timing set. these are simple starts. what intake are you running? which throttle body? have you increased the fuel pressure?
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Old 12-10-2010, 08:36 PM   #14
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Re: Big cam in 350 tbi, high idle...

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Originally Posted by bigbadjohn84 View Post
dude, that cam is tiny. you have some issues elsewhere. I am running a 383 with .510 lift in mine, well .522 with the 1.6 rockers. you need to check a few things. number one, with larger cam, more air is sucked into the cylinders by the longer valve cycle. as stated before, you need to check min idle setting, reset the IAC, be sure timing is set at 0 with timing port unplugged unless you are running advance in your timing set. these are simple starts. what intake are you running? which throttle body? have you increased the fuel pressure?
i'm thinking about doing the same thing with a 305 with a lopey cam in it.

it's a 90 and i'd be using the stock 350 throttle body that is on it now. should i up the fuel pressure on it or should the smaller cubes be ok with the 350 TBI?

how do i check min idle setting and reset the IAC? sorry i don't know anything about TBI systems.
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Old 12-10-2010, 09:35 PM   #15
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Re: Big cam in 350 tbi, high idle...

Just had better read up on cam swaps if your going to keep a "stock" TBI, if you start throwing big cams in a stock TBI truck and think it will run right, it wont..
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