High Idle - Page 2 - ZR-1 Net Registry Forums

zr1don · 02-11-2011

RedRiderZR1,
Thanks for the info, my stock cats were blown out two years ago and I replaced w/aftermarket headers and cats. I have been trying since last August to pass and haven't yet (despite numerous changes and tries). Was hoping you had a stock system to compare against, thanks again for the info. Apologize for hijacking your thread, hope you get your idle fixed.

RedRiderZR1 · 02-11-2011

Quote:

Originally Posted by Aurora40

I used TB cleaner and it did just what he is describing. At the time I didn't know anyone with a ZR-1, and had no idea how to fix it. Since a new TB was like a grand from GM, I put that grand towards a Haibeck ported plenum since the TB was also ported (thus solving the DAG issue).

Not great news there. I would of thought throttle body cleaner would be safe. Odd though, after I blip the throttle it goes back down. So it sounds as if it is hanging up until I blip the throttle. Well I will have to check it out. All good info. Thanks.

RedRiderZR1 · 02-11-2011

Quote:

Originally Posted by zr1don

RedRiderZR1,
Thanks for the info, my stock cats were blown out two years ago and I replaced w/aftermarket headers and cats. I have been trying since last August to pass and haven't yet (despite numerous changes and tries). Was hoping you had a stock system to compare against, thanks again for the info. Apologize for hijacking your thread, hope you get your idle fixed.

No problem. From what i have read here lately, it seems people with the stock manifolds and cats have a better chance of getting them through. Most likely due to the cats being closer to the engine on the stock manifolds. Hope you get it passed soon.

Greg

mike100 · 02-17-2011

my NOx was pretty high when I transferred from the previous owner's smog (the rest of the numbers were real low), but I think it was elevated combustion temps due to running lean. It had a large vacuum leak under the plenum which caused it idle at 1200 rpms all the time and would never slow down.

I may have wiped a little bit of the DAG off the lower half of my t.b., but it still idles below 1000 rpms now and slows down on the road when you let off the accelerator.

to test for a leak:

1) take off the inlet duct and air filter housing
2) clamp the vent hoses that come from the cam covers so they can't bypass air to the engine
3) get a real stiff box or notebook binder and block the front of the air horn when the engine is idling.

if it still runs at 700-800 rpm's, then it has a big air leak somewhere else...if it chokes it, then all the air is going through the throttle body and/or IAC valve. I don't see wiping away some of the DAG making it hang at 1500 rpms.

02-11-2011	#11
zr1don Join Date: Jan 2006 Location: Temecula, CA Posts: 88	Re: High Idle RedRiderZR1, Thanks for the info, my stock cats were blown out two years ago and I replaced w/aftermarket headers and cats. I have been trying since last August to pass and haven't yet (despite numerous changes and tries). Was hoping you had a stock system to compare against, thanks again for the info. Apologize for hijacking your thread, hope you get your idle fixed.

02-17-2011	#14
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,786	Re: High Idle my NOx was pretty high when I transferred from the previous owner's smog (the rest of the numbers were real low), but I think it was elevated combustion temps due to running lean. It had a large vacuum leak under the plenum which caused it idle at 1200 rpms all the time and would never slow down. I may have wiped a little bit of the DAG off the lower half of my t.b., but it still idles below 1000 rpms now and slows down on the road when you let off the accelerator. to test for a leak: 1) take off the inlet duct and air filter housing 2) clamp the vent hoses that come from the cam covers so they can't bypass air to the engine 3) get a real stiff box or notebook binder and block the front of the air horn when the engine is idling. if it still runs at 700-800 rpm's, then it has a big air leak somewhere else...if it chokes it, then all the air is going through the throttle body and/or IAC valve. I don't see wiping away some of the DAG making it hang at 1500 rpms.