Surging Idle & Failed Emissions
10-28-2005, 07:35 PM
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Car: 91 Camaro RS
Engine: 350 Police with some MINOR modifica
Transmission: kitted 700R4 & vette servo
Surging Idle & Failed Emissions
This is what I have....
A 91 RS (ex-TBI 305) with a Carburated 350.
Holley Street Dominator Intake Manifold
600 CFM Four Barrell Street Carburetor
The stock computer is still hooked up, but it has been bypassed to run the carb. I did not put a fuel pressure regulator on, just a return line to the gas tank.
The car runs strong. But every once in awhile (not all the time, starting to become more frequent) I get a surging idle from 500 rpm's up till 1100-1200 rpm's. It is starting to become a pain. What do you suggest I do now?
I also failed emmisions.
My CO2 was passed with a 12.51%
My CO was passed with a 0.01% (max limit is 1.20%)
My HC was failed with a 646 (max limit is 220)
What does this mean anyhow, with the numbers & initials?
What can I do to get this thing to pass?
The guy at the testing site said since everything was all new, it probally just needs to be driven & broke in before it passes. But this guy looked like he knew more about eating paste then he did about cars. The surging idle was also showing a presence when he was testing it.
I was told by locals that if it surges it will fail, but no one was offering suggestions about fixing the problems.
A 91 RS (ex-TBI 305) with a Carburated 350.
Holley Street Dominator Intake Manifold
600 CFM Four Barrell Street Carburetor
The stock computer is still hooked up, but it has been bypassed to run the carb. I did not put a fuel pressure regulator on, just a return line to the gas tank.
The car runs strong. But every once in awhile (not all the time, starting to become more frequent) I get a surging idle from 500 rpm's up till 1100-1200 rpm's. It is starting to become a pain. What do you suggest I do now?
I also failed emmisions.
My CO2 was passed with a 12.51%
My CO was passed with a 0.01% (max limit is 1.20%)
My HC was failed with a 646 (max limit is 220)
What does this mean anyhow, with the numbers & initials?
What can I do to get this thing to pass?
The guy at the testing site said since everything was all new, it probally just needs to be driven & broke in before it passes. But this guy looked like he knew more about eating paste then he did about cars. The surging idle was also showing a presence when he was testing it.
I was told by locals that if it surges it will fail, but no one was offering suggestions about fixing the problems.
10-29-2005, 09:56 AM
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Join Date: Nov 2001
Location: Savannah, GA
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Car: 3
Engine: inboard
Transmission: underfloor
I take it this is strictly a tailpipe test, no "all stock underhood components must be in place" type of thing.
Surge sounds lean, but you say you use no fuel pressure regulator, and I take it you still have the TBI system in tank electric pump? That unregulated puts out way too much pressure for the carburettor, you only need 5-6 psi for that.
And as far as the computer being bypassed, you did install a mechanical/vacuum advance distributor? Once you disable the TBI it is my understanding and I could be wrong that the electronic spark control is no longer working.
Surge sounds lean, but you say you use no fuel pressure regulator, and I take it you still have the TBI system in tank electric pump? That unregulated puts out way too much pressure for the carburettor, you only need 5-6 psi for that.
And as far as the computer being bypassed, you did install a mechanical/vacuum advance distributor? Once you disable the TBI it is my understanding and I could be wrong that the electronic spark control is no longer working.
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