PERF.CAM, EMISSION TUNING
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TECH Apprentice
Joined: Nov 2001
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From: Fort Worth
Re: PERF.CAM, EMISSION TUNING How do we wire up the air pump,at least temperary for inspections? Thanks. This will be very usefull info for me and others.How about a small write up?
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From: new england
PERF.CAM, EMISSION TUNING New to this site, but experienced in emission/perf. tuning.I post this to be helpfull to those who may not have considered this.I chuckle when I read about reprogramming computer to clean up idle emissions after cam swaps.The smell out the pipes is not from rich/lean conditions, its from combustion missfires caused by exhaust dilution of incoming intake charge. This is from increased duration and overlap valve timing. This condition of missfire and late combustion at idle is what causes racy sound also.No programming other than idle speed and to some extent ignition timing is going to affect this in a positive way.Piston speed is what shortens the exhaust dilution window and what allows cam grind to become efficent. IMO the best way to clean up this situation when using a big cam would be to have air injection active in idle situations to cover up the engines sins by promoting converter efficency. Think about it.
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
Re: PERF.CAM, EMISSION TUNING Some have already done what you recommend by hot wiring the AIR pump to run constantly during the test. This injection of fresh air into the exhaust helps to keep the cats hotter and dilute emissions.
Good post, BTW.
[ December 11, 2001: Message edited by: RPM WS6 ]</p>
Good post, BTW.
[ December 11, 2001: Message edited by: RPM WS6 ]</p>
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From: new england
Re: PERF.CAM, EMISSION TUNING TEXAS TA: I looked up the air pump circuit on GM's SI2000 and here is what you need to do. Locate junction block #2(left front engine compartment, block closer to firewall) find air pump relay and splice into brown wire(circuit 436) This is the grounding wire between pcm and terminal 86 of relay. You will need to access bottom side of juntion block, you can verify correct wire by reading terminal 86 off of relay . There is numbers or a schematic on relay. Next I would run this new wire cleanly into interior thru the firewall to a 12volt toggle switch on one side and a ground wire on the other side of switch. Thats it no SES light because PCM doesnt know pump is on .But beware only use air pump at idle or you can overheat converters and damage them. If you spliced(soldered) into brown wire properly you will not disrupt normal air pump use by the PCM. Good luck
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Joined: Dec 2001
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From: new england
Re: PERF.CAM, EMISSION TUNING I have to add this to my post: The secondary air injection solenoid will need to be activated also. This is located on drivers side valve cover. Pink and black wire (circuit 429) to this solenoid will need to be grounded with its own toggle switch, the same way as used by air pump. This allows air from pump to be introduced to exhaust system. Now Im done.
