Different idle with open/closed hood!!
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Different idle with open/closed hood!!
Today - I had to set my idle again... The idle was set too low and so I increased the idle to 1000 RPM... When I closed the hood - the idle would drop to 800 and then shut off .. It seems that I have to set the idle at least 200 rpm higher with the open hood. It seems that the airflow is very restricted with the closed hood... Maybe I should consider removing my 1/2 inch spacer and use a taller air filter or a lower drop - drop base. My current setup has a 1 1/4 inch drop base and a 2 1/4 inch K&N filter...
:cheers:
Olivier
:cheers:
Olivier
Melting Slicks
Joined: Apr 2001
Posts: 2,280
Likes: 0
From: colorado springs CO
Re: Different idle with open/closed hood!! (GrandSportC3)
what intake mani fold u got on there??
ive got a moroso dropbase aircleaner with a 3 inch filter on it..
using the performer 2101 intake....
ive got a moroso dropbase aircleaner with a 3 inch filter on it..
using the performer 2101 intake....
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Re: Different idle with open/closed hood!! (GrandSportC3)
Hi Olivier
Don't you think this has anything to do with the engine compartment heat.
Cold air with hood open, hot air with hood closed.
Your car seems to be very closed up in the front . The lights cover the normaly open intakes.
I see a certain idle speed change at stop and goes with the engine compartment heat soaked on my 68 big block, but it doesn't bother me a lot. Nevertheless, I will install a cold air box onto the L88 hood.
Hey, I wish I had some extra money do get your Duntow Vette.
A real beauty.
Gunther
Don't you think this has anything to do with the engine compartment heat.
Cold air with hood open, hot air with hood closed.
Your car seems to be very closed up in the front . The lights cover the normaly open intakes.
I see a certain idle speed change at stop and goes with the engine compartment heat soaked on my 68 big block, but it doesn't bother me a lot. Nevertheless, I will install a cold air box onto the L88 hood.
Hey, I wish I had some extra money do get your Duntow Vette.
A real beauty.
Gunther
Le Mans Master
Joined: Aug 2000
Posts: 9,662
Likes: 7
From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: Different idle with open/closed hood!! (GrandSportC3)
Are you certain that the aircleaner isn't pressing down on your throttle linkage or cable, with the hood closed? Get some modeling clay or putty and make 4 little ***** about 2 cm in diameter. Place them at the front, back and each side of your aircleaner. Then close the hood and see where it might be touching.
Drifting
Joined: Mar 2001
Posts: 1,514
Likes: 1
Re: Different idle with open/closed hood!! (Smokehouse69)
I kinda thinking along the same lines as Smokehouse69 that the hood closing is moving the throttle. The under hood temp is another plausible cause, but I don't think it would be an instant reaction like your describing. Try closing the hood without an aircleaner on and see if you get the same effect.
Scott
edit(poor spelling :rolleyes: )
[Modified by Scott78, 3:43 PM 7/30/2002]
Scott
edit(poor spelling :rolleyes: )
[Modified by Scott78, 3:43 PM 7/30/2002]
Moderator
Joined: Jun 1999
Posts: 7,117
Likes: 51
From: Dove Mountain Arizona
Re: Different idle with open/closed hood!! (GrandSportC3)
Don't think it has anything to do with hood open/closed. Enough air gets in from under the car/grill, etc, especially with the filter you're running. Methinks your carb linkage is messed up. If you have a worn butterfly shaft for instance, you could set the idle and the action of shutting the hood COULD move it enough to click your idle down, kind of like the fast idle kick-down works. If you're running a DP you might try opening the secondary 'flys a little. Make sure your 'flys are centered in their openings. Just some thoughts, but a closed hood should not do what you describe at all. Well, maybe it could if you had a large drop base and a very thin (say 1" or so) filter. That could cause some air flow problems but I would think that would be at speed and not idle which doesn't require as much air at all. Hope I helped some. :cheers:
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Different idle with open/closed hood!! (daily_driver)
what intake mani fold u got on there??
ive got a moroso dropbase aircleaner with a 3 inch filter on it..
using the performer 2101 intake....
ive got a moroso dropbase aircleaner with a 3 inch filter on it..
using the performer 2101 intake....
:cheers:
Olivier
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Different idle with open/closed hood!! (WESCH)
Hi Olivier
Don't you think this has anything to do with the engine compartment heat.
Cold air with hood open, hot air with hood closed.
Your car seems to be very closed up in the front . The lights cover the normaly open intakes.
I see a certain idle speed change at stop and goes with the engine compartment heat soaked on my 68 big block, but it doesn't bother me a lot. Nevertheless, I will install a cold air box onto the L88 hood.
Hey, I wish I had some extra money do get your Duntow Vette.
A real beauty.
Gunther
Don't you think this has anything to do with the engine compartment heat.
Cold air with hood open, hot air with hood closed.
Your car seems to be very closed up in the front . The lights cover the normaly open intakes.
I see a certain idle speed change at stop and goes with the engine compartment heat soaked on my 68 big block, but it doesn't bother me a lot. Nevertheless, I will install a cold air box onto the L88 hood.
Hey, I wish I had some extra money do get your Duntow Vette.
A real beauty.
Gunther
:cheers: :cheers:
Olivier
[Modified by GrandSportC3, 10:10 PM 7/30/2002]
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Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Different idle with open/closed hood!! (Smokehouse69)
Are you certain that the aircleaner isn't pressing down on your throttle linkage or cable, with the hood closed? Get some modeling clay or putty and make 4 little ***** about 2 cm in diameter. Place them at the front, back and each side of your aircleaner. Then close the hood and see where it might be touching.
:cheers:
Olivier
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Different idle with open/closed hood!! (MasterDave)
Don't think it has anything to do with hood open/closed. Enough air gets in from under the car/grill, etc, especially with the filter you're running. Methinks your carb linkage is messed up. If you have a worn butterfly shaft for instance, you could set the idle and the action of shutting the hood COULD move it enough to click your idle down, kind of like the fast idle kick-down works. If you're running a DP you might try opening the secondary 'flys a little. Make sure your 'flys are centered in their openings. Just some thoughts, but a closed hood should not do what you describe at all. Well, maybe it could if you had a large drop base and a very thin (say 1" or so) filter. That could cause some air flow problems but I would think that would be at speed and not idle which doesn't require as much air at all. Hope I helped some. :cheers:
:cheers:
Olivier
Burning Brakes
Joined: Dec 2000
Posts: 1,183
Likes: 2
From: Des Moines Iowa
Re: Different idle with open/closed hood!! (GrandSportC3)
Suggest you remove both air filter and air cleaner assembly, then check idel speed on warm engine, then close hood and see what you have............if it's air restriction, then removal of above should help situation, if it's really warm/hot air, which I find really hard to believe, then you will still see a difference.
..........Still find it hard to believe that hot air would cause a 200 RPM difference in idel speed................
..........Still find it hard to believe that hot air would cause a 200 RPM difference in idel speed................
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Different idle with open/closed hood!! (john's '81 mouse)
Suggest you remove both air filter and air cleaner assembly, then check idel speed on warm engine, then close hood and see what you have............if it's air restriction, then removal of above should help situation, if it's really warm/hot air, which I find really hard to believe, then you will still see a difference.
..........Still find it hard to believe that hot air would cause a 200 RPM difference in idel speed................
..........Still find it hard to believe that hot air would cause a 200 RPM difference in idel speed................
:cheers:
Olivier