911SC backfire
Thread Starter
Track Day
Joined: Feb 2006
Posts: 21
Likes: 0
From: Covington, God's Country,Ga.
My 471 cu.in. Shelby Cobra is red...not jealous.
Anyway,
1. Nope...two Dempsey books and a useless Haynes Manual.
2.Yep...can adjust that no problem...We sample from the tailpipe..no nipple...no converter.
I think the rpm range is 4000-5500..not sure about the advance sticking...something to look at though.
The problem reminds me of an accelerator pump bypassing on carb cars...no yawning now, ya' hear?
Anyway,
1. Nope...two Dempsey books and a useless Haynes Manual.
2.Yep...can adjust that no problem...We sample from the tailpipe..no nipple...no converter.
I think the rpm range is 4000-5500..not sure about the advance sticking...something to look at though.
The problem reminds me of an accelerator pump bypassing on carb cars...no yawning now, ya' hear?
Instructor
Joined: Oct 2005
Posts: 178
Likes: 0
From: Lake Mary, Florida
Originally Posted by goldrench
My 471 cu.in. Shelby Cobra is red...not jealous.
Anyway,
Anyway,
Rennlist Member
Joined: Oct 2004
Posts: 20,607
Likes: 16
From: Bakersfield, CA, for now...
Yep, the aspirin's starting to work...
OK, the revs that you're using when you get the intake pop indicate that you're driving properly. Taking an exhaust sample from the pipe is good - test should be done at full temp and idling about 900 rpm. With your setup a CO of between 1.2 and 2.0 % will probably work the best.
Your comment regarding a non-functional accel pump is right on the money - now we have to figure out what might cause the same symptom. A sticking or out of adjustment sensor plate might be a good place to start. My thinking is that, if there is a problem with that part, the fuel distributor can't react quickly enough with fuel delivery. If you attempt to check it, and can't find instruction (it sounds like you might be manual-challenged) let me know. I should be able to find the info in my factory books, possibly even fax you the page(s).
Pete
OK, the revs that you're using when you get the intake pop indicate that you're driving properly. Taking an exhaust sample from the pipe is good - test should be done at full temp and idling about 900 rpm. With your setup a CO of between 1.2 and 2.0 % will probably work the best.
Your comment regarding a non-functional accel pump is right on the money - now we have to figure out what might cause the same symptom. A sticking or out of adjustment sensor plate might be a good place to start. My thinking is that, if there is a problem with that part, the fuel distributor can't react quickly enough with fuel delivery. If you attempt to check it, and can't find instruction (it sounds like you might be manual-challenged) let me know. I should be able to find the info in my factory books, possibly even fax you the page(s).
Pete
Thread Starter
Track Day
Joined: Feb 2006
Posts: 21
Likes: 0
From: Covington, God's Country,Ga.
Petty takes "Goody's"...not sure if they're with water or snorted...
Co was 1.4% last time we checked it.
I'm leaning towards the sensor plate too...if you could fax the page(s) over it would help a lot.
Right now it's a hit or miss thing.
Also the vacuum lines are different on the Euro model in a couple of places and there are no Euro vacuum line diagrams I've been able to find.
Fax# 770-788-1328.
BTW: I employ 5 mechanics...2 are ASE Masters, one is L1 ...I am one of them...Rob's brother is the other. This ain't no shadetree operation. www.goldenruleauto.com
Where's my box of Goody's? Darn this hurts.
Co was 1.4% last time we checked it.
I'm leaning towards the sensor plate too...if you could fax the page(s) over it would help a lot.
Right now it's a hit or miss thing.
Also the vacuum lines are different on the Euro model in a couple of places and there are no Euro vacuum line diagrams I've been able to find.
Fax# 770-788-1328.
BTW: I employ 5 mechanics...2 are ASE Masters, one is L1 ...I am one of them...Rob's brother is the other. This ain't no shadetree operation. www.goldenruleauto.com
Where's my box of Goody's? Darn this hurts.
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Michael S. Palmer
Rennlist Member
Joined: Oct 2004
Posts: 20,607
Likes: 16
From: Bakersfield, CA, for now...
Dad: Yes, if your CO% is set at 1.4 you probably have a cold control pressure issue, in other words, too much pressure at the top of the fuel distributor, which will create a lean mixture during cold running (this setting is the job of the warm up regulator). Or, it could be the toilet bowl, OOPS, POP-OFF VALVE, seal leaking unmetered air, or an intake leak, etc...
Pete
Pete
Three Wheelin'
Joined: Feb 2003
Posts: 1,698
Likes: 90
From: Santa Barbara, CA
Pete, thought I'd chime in here with an OT question just to keep things fresh and interesting: are you heading up to the Ventura Show by any chance this weekend?
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Chris Andropoulos
Schneider Autohaus
Santa Barbara, CA
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Chris Andropoulos
Schneider Autohaus
Santa Barbara, CA
Rennlist Member
Joined: Oct 2004
Posts: 20,607
Likes: 16
From: Bakersfield, CA, for now...
Hi Chris, unfortunately I can't make it. I'm having a very minor medical procedure Friday, which will keep me down for a couple of days, which makes a mess out of the weekend! Rats!!
Pete
Pete
