C4 Emissions problems
Thread Starter
7th Gear
Joined: Aug 2007
Posts: 7
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C4 Emissions problems
I recently bought 1990 Corvette with a Paxton SN89 supercharger, Lingenfelter intake and a 412 cu in engine. It has an aftermarket fuel management system running Calmap 6 (yeah I know that's old). It has 55# fuel injectors. The oil and coolant temps are in the middle of the gauges. It came without the cat's installed (pipe all the way back). The dealer estimated that the car has nearly 600 HP.
I bought it from a local small Corvette dealer and they are responsible for the emissions. They have put in new spark plugs, cap, rotor & wires. They also installed a pair of high flow cat's.
The emissions are high CO an high HC. It has extremely low NOx. The oil and coolant temps are higher, but not maxed out. They are trying 35# injectors and a tune in the fuel management system. It's close to passing the emissions test.
Anyone have any ideas? I am soooo frustrated about this. They have had my car for 10 weeks. The dealer has spent nearly $2000 to get my car to pass emissions.
Thanks.
I bought it from a local small Corvette dealer and they are responsible for the emissions. They have put in new spark plugs, cap, rotor & wires. They also installed a pair of high flow cat's.
The emissions are high CO an high HC. It has extremely low NOx. The oil and coolant temps are higher, but not maxed out. They are trying 35# injectors and a tune in the fuel management system. It's close to passing the emissions test.
Anyone have any ideas? I am soooo frustrated about this. They have had my car for 10 weeks. The dealer has spent nearly $2000 to get my car to pass emissions.
Thanks.
Last edited by bconlon; Sep 11, 2007 at 12:05 AM. Reason: add more information
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
What are the limits in your state and what is the car at now? If it's going to require detuning it and struggling every 2 years to pass, maybe you'll want to just find a friendly smog guy instead. Or do you only have to smog on change of ownership?
Thread Starter
7th Gear
Joined: Aug 2007
Posts: 7
Likes: 0
It actually passed one time with the 55# injectors, but then someone at the emissions station with some knowledge noticed that it didn't have an air pump. So it failed the visual inspection.
I have seen the emissions reports (it's been tested at least 5 times), but I don't have them right now (the dealer has them).
I suggested that maybe we try to test it without the supercharger belt on. I have another belt so I can run without the supercharger, if I want to. I figure if there's less air flow, there will be less fuel. When I bought it, the supercharger was seized up and it had the smaller belt on it. I bought the rebuild kit, rebuilt it and installed the larger belt. It ran well without the supercharger, but there's definitely more power with the supercharger!
Any ideas?
I have seen the emissions reports (it's been tested at least 5 times), but I don't have them right now (the dealer has them).
I suggested that maybe we try to test it without the supercharger belt on. I have another belt so I can run without the supercharger, if I want to. I figure if there's less air flow, there will be less fuel. When I bought it, the supercharger was seized up and it had the smaller belt on it. I bought the rebuild kit, rebuilt it and installed the larger belt. It ran well without the supercharger, but there's definitely more power with the supercharger!
Any ideas?
Instructor
Joined: Jul 2007
Posts: 174
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From: Toronto Ontario
If you can find a competent tuner in your area have him (or her) tune the vette so it could pass emissions. Also, make sure you have the correct temp rated spark plugs for your engine. I suggest a cooler set.
