Very high idle when breathers hooked up
#2695950
09/09/19 09:21 PM
09/09/19 09:21 PM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
super stock
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OP
super stock
Joined: Jun 2007
Posts: 1,184
clarks summit pa
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I'm having multiple issues with my motor currently that I believe one of the possibilities that are causing them are a crankcase pressure issue. My engine has the moroso billet positive locking breathers ( part number 68788) on each valve cover. Originally I had both breathers just left open venting to the air. Now I am almost convinced that I have too much crankcase pressure building up causing my rear main seal leak. So I left the one breather open as an inlet for air into the engine and I hooked the other breather to the pcv port on the front carburetor. The engine seems to start a little easier and not run as rich as before, however I cannot get the idle speed lower than roughly 1800 to 2000 rpm. I have the idle speed screws backed all of the way out on both carburetors but it still idles very high. Am I missing something with how these breathers are supposed to be hooked up?
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Very high idle when breathers hooked up
[Re: stumpy]
#2695954
09/09/19 09:37 PM
09/09/19 09:37 PM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
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super stock
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OP
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clarks summit pa
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I don't believe so, but I will double check. Are you referring to the slack between the linkage from the front to rear carburetor, or in the throttle cable to carburetor?
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Very high idle when breathers hooked up
[Re: CSK]
#2695961
09/09/19 09:54 PM
09/09/19 09:54 PM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
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OP
super stock
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clarks summit pa
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I tried checking for vacuum leaks around the intake and I couldn't find any. The idle is around 900-1000 without the breathers hooked up. Wouldn't this rule out the intake gaskets? Engine vacuum is low, but I'm not sure if that's just because of the camshaft though. The motor has less than 200 miles on it and I've had nothing but issues since the day I ordered it.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Very high idle when breathers hooked up
[Re: 73cuda340]
#2695985
09/09/19 11:01 PM
09/09/19 11:01 PM
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Joined: Jan 2003
Posts: 32,984 Grand Prairie,Texas
stumpy
I Win
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I Win
Joined: Jan 2003
Posts: 32,984
Grand Prairie,Texas
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I don't believe so, but I will double check. Are you referring to the slack between the linkage from the front to rear carburetor, or in the throttle cable to carburetor? Talking about any of the linkage that my be holding the throttle open a little.
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Re: Very high idle when breathers hooked up
[Re: 73cuda340]
#2696009
09/10/19 12:29 AM
09/10/19 12:29 AM
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Joined: Aug 2011
Posts: 2,872 Pattison Texas
CSK
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master
Joined: Aug 2011
Posts: 2,872
Pattison Texas
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I tried checking for vacuum leaks around the intake and I couldn't find any. The idle is around 900-1000 without the breathers hooked up. Wouldn't this rule out the intake gaskets? Engine vacuum is low, but I'm not sure if that's just because of the camshaft though. The motor has less than 200 miles on it and I've had nothing but issues since the day I ordered it. what engine is it ? intake could be leaking on the underside in the valley,
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: Very high idle when breathers hooked up
[Re: CSK]
#2696089
09/10/19 11:04 AM
09/10/19 11:04 AM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
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OP
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clarks summit pa
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528 hemi. Stock 2x4 intake
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Very high idle when breathers hooked up
[Re: topside]
#2696331
09/10/19 10:01 PM
09/10/19 10:01 PM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
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clarks summit pa
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I will double check the linkage tomorrow. There isn't a pcv valve at all. Just one of the breathers that I have listed on each valve cover. I found that strange, but that is how I received the engine right from the engine builder. I called moroso earlier and the guy told me that these breathers are meant to be used with an evacuation system tied in with the headers, and by having one of the breathers hooked up to the carburetor it may be pulling too much air into the motor leaning it out and causing the high idle. I just find it strange that it is making that big of a difference just by hooking a breather up.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Very high idle when breathers hooked up
[Re: 73cuda340]
#2696332
09/10/19 10:03 PM
09/10/19 10:03 PM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
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OP
super stock
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clarks summit pa
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I will check for a vacuum leak at the intake as well when I refill all the oil in the motor and I'm able to run it again.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Very high idle when breathers hooked up
[Re: stumpy]
#2696676
09/11/19 07:48 PM
09/11/19 07:48 PM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
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OP
super stock
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Posts: 1,184
clarks summit pa
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I checked the linkage. There is slack in it and nothing seems to be binding.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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Re: Very high idle when breathers hooked up
[Re: 73cuda340]
#2696749
09/11/19 11:05 PM
09/11/19 11:05 PM
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Joined: Jan 2011
Posts: 4,785 Utah and Alaska
astjp2
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master
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Utah and Alaska
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Is the engine running too rich?
1941 Taylorcraft 1968 Charger 1994 Wrangler 1998 Wrangler 2008 Kia Rio 2017 Jetta
I didn't do 4 years and 9 months of Graduate School to be called Mister!
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Re: Very high idle when breathers hooked up
[Re: stumpy]
#2697156
09/13/19 11:30 AM
09/13/19 11:30 AM
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Joined: Feb 2014
Posts: 1,713 central il.
second 70
top fuel
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top fuel
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central il.
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By hooking the breather up to the carb with out a PCV valve you created a big vacuum leak. I agree with Stumpy after rereading your post you added a huge vacuum leak. That breather is not meant to have vacuum on it. The result you're having is the same as if you just pulled the plug off the pvc port on the carb and left it open. You need to take that off and if needed add a pvc valve.
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Re: Very high idle when breathers hooked up
[Re: second 70]
#2697315
09/13/19 08:52 PM
09/13/19 08:52 PM
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Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
super stock
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OP
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Posts: 1,184
clarks summit pa
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I see it know as well how it created a vacuum leak. I'm not too sure how I didn't realize it at the time. The engine is running very rich, so by having the carburetor draw all of that extra air in, it leaned out the mixture causing the idle to jump up that high. I was originally only running the hose from the breather to try and help eliminate any pressure that may have been building up inside of it.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
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