failed the sniffer today - LOW SPEED HC's - HELP!
02-21-2002, 03:49 PM
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Re: failed the sniffer today - LOW SPEED HC's - HELP! will running restrictor plates in the air tubes on the headers (to help keep the check valves quiet) cause anything?
02-21-2002, 03:52 PM
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Re: failed the sniffer today - LOW SPEED HC's - HELP! Another thing to do is rig the AIR pump to stay on and take out those restrictors. The AIR pump is located in front of the car, below the driver's side headlite, accessible from underneath.
02-21-2002, 07:33 PM
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Re: failed the sniffer today - LOW SPEED HC's - HELP! Glenn, air pump only runs when car is cold, so hot engine testing wont detect restrictors in air system.PSJ's idea about running air pump(hot wire it on) is a good one that would cover a lot of emission sins when testing. The important thing with doing that is to understand that pumping air in will overheat and damage converters if left on too long or as you drive around.Used in moderation for test would work great IMO.
02-23-2002, 04:39 PM
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Re: failed the sniffer today - LOW SPEED HC's - HELP! John,
I do not know exactly what he tweaked, but the conversation and the actual "tests" I witnessed while there where based on fuel/air adjustments and timing. I was at his shop for 4 days and would stop in once and a while. That particular day, I had been there for about 2 hours and pretty much had to leave(Steve is a great guy, just can't take too much in one sitting...).
Todd
I do not know exactly what he tweaked, but the conversation and the actual "tests" I witnessed while there where based on fuel/air adjustments and timing. I was at his shop for 4 days and would stop in once and a while. That particular day, I had been there for about 2 hours and pretty much had to leave(Steve is a great guy, just can't take too much in one sitting...).
Todd
02-23-2002, 06:45 PM
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Re: failed the sniffer today - LOW SPEED HC's - HELP! [quote]Another thing to do is rig the AIR pump to stay on and take out those restrictors. The AIR pump is located in front of the car, below the driver's side headlite, accessible from underneath.<hr></blockquote>
that's an old trick.. from the old days, for older systems where there was a air pipe leading into the converters.
Will not work on the ls1 as the airpump fittings are before the o2's!
This is why the air pump on a ls1 cycles for a few short seconds at startup only when the car is in open loop and does not run in closed loop.
Rigging the airpump to come on without relocating the air fittings after the 02's will only create a super lean condition as sensed by the o2, which the pcm will respond by dumping fuel to correct and the car will run like total **** and your emissions will go through the roof!
It would be sort of like a gigantic exhaust leak.
Steve
that's an old trick.. from the old days, for older systems where there was a air pipe leading into the converters.
Will not work on the ls1 as the airpump fittings are before the o2's!
This is why the air pump on a ls1 cycles for a few short seconds at startup only when the car is in open loop and does not run in closed loop.
Rigging the airpump to come on without relocating the air fittings after the 02's will only create a super lean condition as sensed by the o2, which the pcm will respond by dumping fuel to correct and the car will run like total **** and your emissions will go through the roof!
It would be sort of like a gigantic exhaust leak.
Steve
