LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Deleting emissions stuff. Help!!!

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Old 12-15-2010, 11:32 PM
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Default Deleting emissions stuff. Help!!!

Ok im kinda new on the lt1 scene and to ls1 tech so take it easy on me if i ask something stupid ha ha. Alright Im wanting to delete as much emissions stuff as possible, cat,o2s, maf,egr,air,ect on my 95z. right now its stock minus cai but ill be pulling the motor again in feb having a 383 built probably by AI and buying a performabuilt a4. where do i start and how tough is this gona be?
Old 12-16-2010, 12:05 AM
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Unless you plan on converting to an open loop tune, you need to keep your O2 sensors - they are crucial for fuel trim. Same with the MAF - keep it.

Removing the EGR is easy - just remove the solenoid, valve, install blockoff plates (available from several site sponsors and eBay), and have it tuned out of the PCM.

The AIR system is also easily deleted. Remove the pump, lines, and check valves off of the manifolds, and install plugs. Assuming you have a 95, you'll need an M22 drain plug for the manifolds and a 5/8" vacuum cap for the intake ducting. Leave the fuse in the fusebox and tuning won't be required.

The EVAP system is fairly straightforward too. Obviously remove everything, including the lines, purge solenoid (on the passenger side of the intake manifold), plug the fitting on the throttle body, remove the charcoal canister behind the driver side rear wheel well. Take the line off of the canister (the one from the fuel tank) and install a small breather. You'll get a bit of a fuel smell from the rear of the car, but that's to be expected.

And good choice on those parts. I hear AI-headed 383s and Performabuilt transmissions work well together.
Old 12-16-2010, 12:09 AM
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Originally Posted by RamAir95TA
Unless you plan on converting to an open loop tune, you need to keep your O2 sensors - they are crucial for fuel trim. Same with the MAF - keep it.

Removing the EGR is easy - just remove the solenoid, valve, install blockoff plates (available from several site sponsors and eBay), and have it tuned out of the PCM.

The AIR system is also easily deleted. Remove the pump, lines, and check valves off of the manifolds, and install plugs. Assuming you have a 95, you'll need an M22 drain plug for the manifolds and a 5/8" vacuum cap for the intake ducting. Leave the fuse in the fusebox and tuning won't be required.

The EVAP system is fairly straightforward too. Obviously remove everything, including the lines, purge solenoid (on the passenger side of the intake manifold), plug the fitting on the throttle body, remove the charcoal canister behind the driver side rear wheel well. Take the line off of the canister (the one from the fuel tank) and install a small breather. You'll get a bit of a fuel smell from the rear of the car, but that's to be expected.

And good choice on those parts. I hear AI-headed 383s and Performabuilt transmissions work well together.
i second. definately keep your o2's and MAF
Old 12-16-2010, 01:21 AM
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Ok I appreciate the help. Shouldnt be to hard to get that stuff out of the way. As far as the cat goes it only has 1 and the only o2s it has are on the down pipes so deleting the cat wont cause any problems right?
Old 12-16-2010, 07:49 AM
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^yep you're right.......cut the cat out and put in a piece of pipe..........and listen to RamAir above the AI Heads and Cams run like a bat out of hell.......see my sig ....good luck!!!
Old 12-16-2010, 11:05 AM
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Nope...deleting the cat won't cause any issues. Now if you had an OBDII car it would be a different story.
Old 12-16-2010, 01:01 PM
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Originally Posted by RamAir95TA
Nope...deleting the cat won't cause any issues. Now if you had an OBDII car it would be a different story.


What happens on OBDII cars?
Old 12-16-2010, 01:10 PM
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^Engine Light
Old 12-16-2010, 01:41 PM
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You would either need O2 simulators or program them out of the PCM.
Old 12-17-2010, 03:11 PM
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Can you recommend or direct me to someone who sells o2 sensor simulators
Old 12-17-2010, 03:17 PM
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Originally Posted by c_smalling
Can you recommend or direct me to someone who sells o2 sensor simulators
http://www.speedinc.com/catagory.cfm.../%20Electrical

Remember these are for POST-CAT sensors, NOT pre-cat.
Old 12-17-2010, 05:23 PM
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Default ok, now pre cat

Thanks for replying RamAir, are there pre-cat sensor replacements? I need the pre-cat type. I have tried some (unsure of the manufacturer) and they didn't work. I had to wire them in to the O2 sensor wiring, as opposed to a plug in installation like the speed power one, and I still got the SES code.
Old 12-17-2010, 05:27 PM
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Unless you're running an open loop tune (or are going carb), you NEED functioning oxygen sensors. This was mentioned in my first post. They are responsible for fuel trim.
Old 12-17-2010, 05:44 PM
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Default here's the deal

OK. I have deleted the air pump and I keep getting SES light and O2 sensor codes. I read that the reason for this is that the O2 sensors sense that the pump is not operating. I would surmise it is because they are not getting the proper amt. of extra air and therefore throw codes.
Please help me eliminate the codes. I have contacted PCM tuners about this and was told that they could program the PCM to not use the pre-cat sensor input. My mileage has dropped considerably since removing the air pump because it is running in the open loop mode
I hope to regain the pre-delete mileage by making a fix by whatever means.
Old 12-17-2010, 07:13 PM
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Specifically, what number codes are you getting?

The AIR pump and O2 codes are not related. When you delete the AIR pump (assuming you have an OBDII car) and the PCM calls for AIR pump operation, the PCM looks for the change in A/F ratio in closed loop via readings from the O2s.

What tuners are you contacting? I have a hard time believing any respected tuner would recommend tuning out the O2s in order to clear an AIR pump code. You are making this much harder on yourself, especially when all you need to do is have the AIR pump programmed out.

Have the AIR pump code programmed out, fix your hacked O2 wiring, and install AC Delco 4-pin O2s.
Old 12-17-2010, 07:18 PM
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sorry i'm jumping in on this thread...
but if you delete the AIR stuff from an OBDI / LT1 car, you still have to have the AIR programmed out of the ECU?
Old 12-17-2010, 07:53 PM
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Nope. Just make sure there's a good fuse in the system.
Old 12-17-2010, 11:46 PM
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^^^ PS...that's me posting on another friends name. Woops.
Old 12-19-2010, 01:20 PM
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Default Advance Auto diag.

AA diagnosed my light with a OBD II scanner(?)
Upon reading the codes it was discovered that at least 1 of the pre cat O2 sensors were throwing codes. Now, it has been at least a year and I can't remember too many of the specifics.
I believe that you are saying that the codes have nothing to do with the air pump being gone., soo...
I just need to replace the offending o2 sensor(s) and I'll be good to go.
Old 12-19-2010, 02:58 PM
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Again, specifically, what code are you getting?

Swap the passenger O2 with the driver O2 and see if the code follows the sensor. If it does it's a sensor/wiring issue. If it stays on that particular bank then you've got other issues to worry about.


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