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Car hads a dead spot when cold

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Old Mar 31, 2008 | 09:28 PM
  #1  
mxcrazed's Avatar
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From: eastern mass
Car: 87 firebird none soon
Engine: None
Transmission: none
Axle/Gears: 2.73 10 bolt
Car hads a dead spot when cold

Hey guys I have a carbed engine (lg4) and it does not have functional heat risers or choke (edelbrock 1406) but it starts up fine even below freezing. The problem is one dead spot just off idle from about 1200rpm to about 2000rpm then it will screw but uitill it is above 100* it is very difficult to drive. I would let it warm up more but also does not have functional E-brakes, has a T5 and I live on a hill. Is this entirely normal, what would you do to help eliminate or minimize this?
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Old Apr 1, 2008 | 12:11 AM
  #2  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Dual snorkel air cleaner with functioning thermovac.

Even better, dual snorkel air cleaner with functioning thermovac and put the stock q-jet system back on.
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Old Apr 1, 2008 | 11:54 AM
  #3  
mxcrazed's Avatar
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Joined: Jan 2007
Posts: 385
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From: eastern mass
Car: 87 firebird none soon
Engine: None
Transmission: none
Axle/Gears: 2.73 10 bolt
Re: Car hads a dead spot when cold

Dual snorkel is out of the question I believe because of the performer rpm and the low fire bird hood the air cleaner sticks out above the hood. I plan on putting on a Q-jet but I think I'll have to get a new wiring harness. How much will the Q-jet choke my 355? Do you think that I could tune out the dead spot?
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Old Apr 1, 2008 | 02:39 PM
  #4  
five7kid's Avatar
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25 Year Member
iTrader: (14)
 
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Well, let's see: The 1406 flows 600 CFM, the q-jet 750 CFM.

Who's choking who?

Common myth: The q-jet hinders power.

Busted!

Since you have a T5, you could consider a double pumper (although it, like the Performer, isn't emissions-legal). A 700-750 would do the job.

You should be able to put some kind of dual snorkel on, even under a 'Bird hood.
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Old Apr 1, 2008 | 09:19 PM
  #5  
mxcrazed's Avatar
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Joined: Jan 2007
Posts: 385
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From: eastern mass
Car: 87 firebird none soon
Engine: None
Transmission: none
Axle/Gears: 2.73 10 bolt
Re: Car hads a dead spot when cold

Well I Totally agree with you that the 1406 was a bad choice, it was installed on the 305 by the previous owner. I guess next time I am at the junk yard I will have to steal the Q-jet off of the beautiful 2 tone baby / navy blue Berlinetta that is still complete and only has one minor dent and little rust. I hate pulling parts off of nice cars it really bothers me I don't even know why it is there but between the 86' 2.4 mpfi the 91' 3.1 mpfi (red on black) the Berlinetta lg4 and the 98' Vortec Tahoe I have everything I could want at my local junkie. The guy only wants $100 for a pair of vortec heads if he only knew what the go for I can't wait to buy them with my tax return!
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